Patent Publication Number: US-11656751-B2

Title: User interface for manipulating user interface objects with magnetic properties

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/655,253, filed Jul. 20, 2017, entitled “USER INTERFACE FOR MANIPULATING USER INTERFACE OBJECTS WITH MAGNETIC PROPERTIES”, which is a continuation of U.S. patent application Ser. No. 15/049,064, filed Feb. 20, 2016, entitled “USER INTERFACE FOR MANIPULATING USER INTERFACE OBJECTS WITH MAGNETIC PROPERTIES”, which is a continuation of International Patent Application Serial Number PCT/US2014/053961, filed Sep. 3, 2014, entitled “USER INTERFACE FOR MANIPULATING USER INTERFACE OBJECTS WITH MAGNETIC PROPERTIES”, which claims priority to U.S. Provisional Patent Application Ser. No. 61/873,356, filed Sep. 3, 2013, entitled “CROWN INPUT FOR A WEARABLE ELECTRONIC DEVICE”; U.S. Provisional Patent Application Ser. No. 61/873,359, filed Sep. 3, 2013, entitled “USER INTERFACE OBJECT MANIPULATIONS IN A USER INTERFACE”; U.S. Provisional Patent Application Ser. No. 61/959,851, filed Sep. 3, 2013, entitled “USER INTERFACE FOR MANIPULATING USER INTERFACE OBJECTS”; and U.S. Provisional Patent Application Ser. No. 61/873,360, filed Sep. 3, 2013, entitled “USER INTERFACE FOR MANIPULATING USER INTERFACE OBJECTS WITH MAGNETIC PROPERTIES”. The content of these applications is hereby incorporated by reference in its entirety for all purposes. 
     This application is related to International Patent Application Serial Number PCT/US2014/053951, filed Sep. 3, 2014, entitled “CROWN INPUT FOR A WEARABLE ELECTRONIC DEVICE”; International Patent Application Serial Number PCT/US2014/053957, filed Sep. 3, 2014, entitled “USER INTERFACE FOR MANIPULATING USER INTERFACE OBJECTS”; and International Patent Application Serial Number PCT/US2014/053958 filed Sep. 3, 2014, entitled “USER INTERFACE OBJECT MANIPULATIONS IN A USER INTERFACE”. The content of these applications is hereby incorporated by reference in its entirety for all purposes. 
    
    
     FIELD 
     The present disclosure relates generally to computer user interfaces, and more specifically to manipulating user interface objects using a rotatable input mechanism. 
     BACKGROUND 
     Advanced personal electronic devices can have small form factors. Use of such personal electronic devices involves manipulation of user interface objects on display screens which also have small form factors that complement the design of the personal electronic devices. 
     Exemplary manipulations that users can perform on personal electronic devices include navigating a hierarchy, selecting a user interface object, adjusting the position, zoom, and rotation of user interface objects, or otherwise manipulating user interface objects. Exemplary user interface objects include documents, digital images, video, text, icons, and maps. 
     BRIEF SUMMARY 
     Some techniques for manipulating user interface objects using reduced-size touch-sensitive displays, however, are generally cumbersome and inefficient. For example, it may be difficult for the user to precisely scroll a document object to a scroll position within a range of potential scroll positions that properly aligns the desired content with the viewable display. For another example, it may be difficult for the user to precisely change the magnification of an image object to a desired zoom size within a range of potential zoom size. For another example, it may be difficult to for the user select a particular user interface object. Existing techniques require more time than necessary when the user attempts to perform tasks, wasting user time and device energy. This latter consideration is particularly important in battery-operated devices. Thus, existing methods for manipulating user interface objects on reduced-size touch-sensitive displays can be inefficient and provide less precision than is preferable. 
     Accordingly, there is a need for electronic devices with faster, more efficient, and more precise methods and interfaces for manipulating user interface objects. Such methods and interfaces optionally complement or replace conventional methods for manipulating user interface objects. Such methods and interfaces reduce the cognitive burden on a user and produce a more efficient human-machine interface. For battery-operated computing devices, such methods and interfaces conserve power and increase the time between battery charges. 
     The above deficiencies and other problems associated with user interfaces for computing devices for manipulating user interface objects are reduced or eliminated by the disclosed devices. In some embodiments, the device is a desktop computer. In some embodiments, the device is portable (e.g., a notebook computer, tablet computer, or handheld device). In some embodiments, the device has a touchpad. In some embodiments, the device is user-wearable. In some embodiments, the device has a touch-sensitive display (also known as a “touch screen” or “touch screen display”). In some embodiments, the device has a display and a touch-sensitive surface. In some embodiments, the device has a rotatable input mechanism. In some embodiments, the device has a graphical user interface (GUI), one or more processors, memory and one or more modules, programs or sets of instructions stored in the memory for performing multiple functions. In some embodiments, the user interacts with the GUI primarily through rotation of the rotatable input mechanism and gestures on the touch-sensitive surface. Executable instructions for performing these functions may be included in a computer readable storage medium or other computer program product configured for execution by one or more processors. 
     In accordance with some embodiments, a method is performed at an electronic device with a display and a rotatable input mechanism. The method includes: displaying, on the display, an object in accordance with a value of a characteristic of the object, the value being within a range of values of the characteristic; receiving a user input request, the user input request representing rotation of the rotatable input mechanism; determining whether the value of the characteristic of the object is within a predetermined subset of the range of values of the characteristic; in accordance with a determination that the value of the characteristic of the object is within the predetermined subset of the range of values of the characteristic, updating the value of the characteristic of the object within the range of values of the characteristic based on the user input request and in accordance with a first function; in accordance with a determination that the value of the characteristic of the object is not within the predetermined subset of the range of values of the characteristic, updating the value of the characteristic of the object within the range of values of the characteristic based on the user input request and in accordance with a second function, wherein the first function and the second function are different functions; and updating display of the object in accordance with the updated value of the characteristic of the object. 
     In accordance with some embodiments, a method is performed at an electronic device with a display and a rotatable input mechanism. The method includes: displaying, on the display, an object in accordance with a value of a characteristic of the object, the value being within a range of values of the characteristic; receiving a user input request, the user input request representing rotation of the rotatable input mechanism; in response to receiving the user input request, determining whether the user input request causes the value of the characteristic of the object to transition into range of a zone of an anchor, the anchor having a start value, an intermediate value, and an end value within the range of values of the characteristic, and the zone of the anchor being between the start value and the end value; and in accordance with a determination that the user input request causes the value of the characteristic of the object to transition into range of the zone of the anchor: updating the value of the characteristic of the object based on the intermediate value of the anchor; and updating display of the object in accordance with the updated value of the characteristic of the object. 
     In accordance with some embodiments, a method is performed at an electronic device with a display and a rotatable input mechanism. The method includes: displaying, on the display, an object in accordance with a value of a characteristic of the object, the value being within a range of values of the characteristic; receiving a user input request, the user input request representing rotation of the rotatable input mechanism; in response to receiving the user input request: updating the value of the characteristic of the object within the range of values of the characteristic based on the user input request; updating display of the object in accordance with the updated value of the characteristic of the object; identifying a closest anchor to the updated value of the characteristic of the object, the closest anchor identified from among at least a first anchor having a corresponding intermediate value and a second anchor having a corresponding intermediate value; subsequently updating the value of the characteristic of the object based on the corresponding intermediate value of the identified closest anchor; and updating display of the object in accordance with the subsequently updated value of the characteristic of the object. 
     In accordance with some embodiments, a method is performed at an electronic device with a display and a rotatable input mechanism. The method includes: displaying, on the display, an object, wherein the object is associated with a first marker having a first value and a second marker having a second value, and wherein a value of a characteristic of the object is based on the first value of the first marker; receiving user input representing rotation of the rotatable input mechanism; in response to receiving the user input representing rotation of the rotatable input mechanism, determining whether an attribute of the user input exceeds a threshold value; in accordance with a determination that the attribute of the user input exceeds the threshold value, updating the value of the characteristic of the object based on the second value of the second marker; and updating display of the object in accordance with the updated value of the characteristic of the object. 
     In accordance with some embodiments, a method is performed at an electronic device. The method includes: displaying of a plurality of selectable elements on a touch-sensitive display of a wearable electronic device, each selectable element of the plurality of selectable elements associated with a corresponding magnetic value; determining a change in a crown distance value, wherein the crown distance value is based on an angular displacement of a crown of the wearable electronic device; determining a direction based on a direction of rotation of the physical crown of the wearable electronic device; and in response to determining the change in the crown distance value: moving a focus selector toward an element of the plurality of selectable elements, and changing a focus of an element of the plurality of selectable elements, wherein the movement is at least initially in the determined direction and a rate of the movement is changed based at least on a magnetic value associated with the selection element. 
     In accordance with some embodiments, a method is performed at an electronic device. The method includes: displaying a plurality of selectable elements on a touch-sensitive display of a wearable electronic device, each selectable element of the plurality of selectable elements associated with a corresponding magnetic value; determining a change in a crown distance value, wherein the crown distance value is based on an angular displacement of a physical crown of the wearable electronic device; determining a direction based on a direction of rotation of the crown; and in response to determining the change in the crown distance value: scrolling the plurality of selectable elements on the display in the determined direction, and changing a focus of a selectable element of the plurality of selectable elements, wherein a rate of the scrolling is changed based at least on a virtual magnetic attraction between an element of the plurality of selectable elements and a focus area. 
     In accordance with some embodiments, a method is performed at an electronic device. The method includes: displaying an object on a touch-sensitive display of a wearable electronic device; determining a change in a crown distance value, wherein the crown distance value is based on an angular displacement of a crown; modifying the appearance of the object based on the change in the crown distance value; determining based on the modified appearance of the object whether a criterion is satisfied; and in response to a determination that the criterion is satisfied, generating a tactile output at the wearable electronic device. 
     Thus, devices are provided with faster, more efficient, and more precise methods and interfaces for manipulating user interface objects, thereby increasing the effectiveness, efficiency, and user satisfaction with such devices. Such methods and interfaces may complement or replace conventional methods for manipulating user interface objects. 
    
    
     
       DESCRIPTION OF THE FIGURES 
       For a better understanding of the various described embodiments, reference should be made to the Description of Embodiments below, in conjunction with the following drawings in which like reference numerals refer to corresponding parts throughout the figures. 
         FIG.  1 A  is a block diagram illustrating a portable multifunction device with a touch-sensitive display in accordance with some embodiments. 
         FIG.  1 B  is a block diagram illustrating exemplary components for event handling in accordance with some embodiments. 
         FIG.  2    illustrates a portable multifunction device having a touch screen in accordance with some embodiments. 
         FIG.  3    is a block diagram of an exemplary multifunction device with a display and a touch-sensitive surface in accordance with some embodiments. 
         FIG.  4 A  illustrates an exemplary user interface for a menu of applications on a portable multifunction device in accordance with some embodiments. 
         FIG.  4 B  illustrates an exemplary user interface for a multifunction device with a touch-sensitive surface that is separate from the display in accordance with some embodiments. 
         FIG.  5 A  illustrates a personal electronic device in accordance with some embodiments. 
         FIG.  5 B  is a block diagram illustrating a personal electronic device in accordance with some embodiments. 
         FIG.  5 C  illustrates an exemplary wearable electronic device according to various examples. 
         FIG.  5 D  illustrates a block diagram of an exemplary wearable electronic device according to various examples. 
         FIGS.  6 A- 6 F  illustrate exemplary user interfaces for manipulating a user interface object in accordance with some embodiments. 
         FIG.  7    is a flow diagram illustrating an exemplary process for manipulating a user interface object in accordance with some embodiments. 
         FIGS.  8 A- 8 F  illustrate exemplary user interfaces for manipulating a user interface object in accordance with some embodiments. 
         FIGS.  8 G- 8 H  illustrate exemplary user interfaces for manipulating a user interface object in accordance with some embodiments. 
         FIG.  9 A  is a flow diagram illustrating an exemplary process for manipulating a user interface object in accordance with some embodiments. 
         FIG.  9 B  is a flow diagram illustrating an exemplary process for manipulating a user interface object in accordance with some embodiments. 
         FIGS.  10 A- 10 B  illustrate exemplary user interfaces for manipulating a user interface object in accordance with some embodiments. 
         FIG.  11    is a flow diagram illustrating an exemplary process for manipulating a user interface object in accordance with some embodiments. 
         FIG.  12    illustrates a functional block diagram in accordance with some embodiments. 
         FIGS.  13 A- 13 J  illustrate exemplary graphical user interfaces for selecting an element using physics-based magnetic modeling in accordance with some embodiments. 
         FIG.  13 K  is a flow diagram illustrating an exemplary process for selecting an element using physics-based magnetic modeling in accordance with some embodiments. 
         FIGS.  14 - 21    illustrate exemplary graphical user interfaces for selecting an element from among elements with varying magnetic values in accordance with some embodiments. 
         FIG.  22    is a flow diagram illustrating an exemplary process for selecting an element from among elements with varying magnetic values in accordance with some embodiments. 
         FIGS.  23 - 30    illustrate exemplary graphical user interfaces for selecting an element using physics-based magnetic and spring modeling in accordance with some embodiments. 
         FIG.  31    is a flow diagram illustrating an exemplary process for selecting an element using physics-based magnetic and spring modeling in accordance with some embodiments. 
         FIGS.  32 - 38    illustrate exemplary graphical user interfaces for selecting an element using a focus area and physics-based magnetic modeling. 
         FIG.  39    is a flow diagram illustrating an exemplary process for selecting an element using a focus area and physics-based magnetic modeling. 
         FIGS.  40 - 45    illustrate exemplary graphical user interfaces for selecting an element using a focus area and physics-based magnetic and spring modeling. 
         FIG.  46    is a flow diagram illustrating an exemplary process for selecting an element using a focus area and physics-based magnetic and spring modeling. 
         FIG.  47    illustrates an exemplary computing system for manipulating a user interface in response to a rotation of a crown according to various examples. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The following description sets forth exemplary methods, parameters and the like. It should be recognized, however, that such description is not intended as a limitation on the scope of the present disclosure but is instead provided as a description of exemplary embodiments. 
     There is a need for electronic devices that provide efficient and precise access to manipulate user interface objects. For example, ease of use for scrolling a document, zooming an image, rotating an image, and selecting an option from among a plurality of options contribute to the efficiency of manipulating user interface objects. Such techniques can reduce the cognitive burden on a user who manipulates user interface objects, thereby enhancing productivity. Further, such techniques can reduce processor and battery power otherwise wasted on redundant user inputs. 
     Below,  FIGS.  1 A- 1 B,  2 ,  3 ,  4 A- 4 B, and  5 A- 5 D  provide a description of exemplary devices for performing the techniques for manipulating user interface objects.  FIGS.  6 A- 6 F,  8 A- 8 H,  10 A- 10 B,  13 A- 13 J,  14 - 21 ,  23 - 30 ,  32 - 38 , and  40 - 45    illustrate exemplary user interfaces for manipulating user interface objects. The user interfaces in the figures are also used to illustrate the processes described below, including the processes in  FIGS.  7 ,  9 A,  9 B,  11 ,  13 K,  22 ,  31 ,  39 , and  46   . 
     Although the following description uses terms first, second, etc. to describe various elements, these elements should not be limited by the terms. These terms are only used to distinguish one element from another. For example, a first touch could be termed a second touch, and, similarly, a second touch could be termed a first touch, without departing from the scope of the various described embodiments. The first touch and the second touch are both touches, but they are not the same touch. 
     The terminology used in the description of the various described embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various described embodiments and the appended claims, the singular forms “a”, “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     The term “if” may be construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” may be construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event],” depending on the context. 
     Embodiments of electronic devices, user interfaces for such devices, and associated processes for using such devices are described. In some embodiments, the device is a portable communications device, such as a mobile telephone, that also contains other functions, such as PDA and/or music player functions. Exemplary embodiments of portable multifunction devices include, without limitation, the iPhone®, iPod Touch®, and iPad® devices from Apple Inc. of Cupertino, Calif. Other portable electronic devices, such as laptops or tablet computers with touch-sensitive surfaces (e.g., touch screen displays and/or touch pads), are, optionally, used. It should also be understood that, in some embodiments, the device is not a portable communications device, but is a desktop computer with a touch-sensitive surface (e.g., a touch screen display and/or a touch pad). 
     In the discussion that follows, an electronic device that includes a display and a touch-sensitive surface is described. It should be understood, however, that the electronic device optionally includes one or more other physical user-interface devices, such as a physical keyboard, a mouse and/or a joystick. 
     The device may support a variety of applications, such as one or more of the following: a drawing application, a presentation application, a word processing application, a website creation application, a disk authoring application, a spreadsheet application, a gaming application, a telephone application, a video conferencing application, an e-mail application, an instant messaging application, a workout support application, a photo management application, a digital camera application, a digital video camera application, a web browsing application, a digital music player application, and/or a digital video player application. 
     The various applications that are executed on the device optionally use at least one common physical user-interface device, such as the touch-sensitive surface. One or more functions of the touch-sensitive surface as well as corresponding information displayed on the device are, optionally, adjusted and/or varied from one application to the next and/or within a respective application. In this way, a common physical architecture (such as the touch-sensitive surface) of the device optionally supports the variety of applications with user interfaces that are intuitive and transparent to the user. 
     Attention is now directed toward embodiments of portable devices with touch-sensitive displays.  FIG.  1 A  is a block diagram illustrating portable multifunction device  100  with touch-sensitive displays  112  in accordance with some embodiments. Touch-sensitive display  112  is sometimes called a “touch screen” for convenience, and is sometimes known as or called a touch-sensitive display system. Device  100  includes memory  102  (which optionally includes one or more computer readable storage mediums), memory controller  122 , one or more processing units (CPU&#39;s)  120 , peripherals interface  118 , RF circuitry  108 , audio circuitry  110 , speaker  111 , microphone  113 , input/output (I/O) subsystem  106 , other input or control devices  116 , and external port  124 . Device  100  optionally includes one or more optical sensors  164 . Device  100  optionally includes one or more intensity sensors  165  for detecting intensity of contacts on device  100  (e.g., a touch-sensitive surface such as touch-sensitive display system  112  of device  100 ). Device  100  optionally includes one or more tactile output generators  167  for generating tactile outputs on device  100  (e.g., generating tactile outputs on a touch-sensitive surface such as touch-sensitive display system  112  of device  100  or touchpad  355  of device  300 ). These components optionally communicate over one or more communication buses or signal lines  103 . 
     As used in the specification and claims, the term “intensity” of a contact on a touch-sensitive surface refers to the force or pressure (force per unit area) of a contact (e.g., a finger contact) on the touch sensitive surface. The intensity of a contact has a range of values that includes at least four distinct values and more typically includes hundreds of distinct values (e.g., at least 256). Intensity of a contact is, optionally, determined (or measured) using various approaches and various sensors or combinations of sensors. For example, one or more force sensors underneath or adjacent to the touch-sensitive surface are, optionally, used to measure force at various points on the touch-sensitive surface. In some implementations, force measurements from multiple force sensors are combined (e.g., a weighted average) to determine an estimated force of a contact. Using the intensity of a contact as an attribute of a user input allows for user access to additional device functionality that may otherwise not be accessible by the user on a reduced-size device with limited real estate for displaying affordances (e.g., on a touch-sensitive display) and/or receiving user input (e.g., via a touch-sensitive display, a touch-sensitive surface, or a physical/mechanical control such as a knob or a button). 
     As used in the specification and claims, the term “tactile output” refers to physical displacement of a device relative to a previous position of the device, physical displacement of a component (e.g., a touch-sensitive surface) of a device relative to another component (e.g., housing) of the device, or displacement of the component relative to a center of mass of the device that will be detected by a user with the user&#39;s sense of touch. For example, in situations where the device or the component of the device is in contact with a surface of a user that is sensitive to touch (e.g., a finger, palm, or other part of a user&#39;s hand), the tactile output generated by the physical displacement will be interpreted by the user as a tactile sensation corresponding to a perceived change in physical characteristics of the device or the component of the device. For example, movement of a touch-sensitive surface (e.g., a touch-sensitive display or trackpad) is, optionally, interpreted by the user as a “down click” or “up click” of a physical actuator button. In some cases, a user will feel a tactile sensation such as an “down click” or “up click” even when there is no movement of a physical actuator button associated with the touch-sensitive surface that is physically pressed (e.g., displaced) by the user&#39;s movements. As another example, movement of the touch-sensitive surface is, optionally, interpreted or sensed by the user as “roughness” of the touch-sensitive surface, even when there is no change in smoothness of the touch-sensitive surface. While such interpretations of touch by a user will be subject to the individualized sensory perceptions of the user, there are many sensory perceptions of touch that are common to a large majority of users. Thus, when a tactile output is described as corresponding to a particular sensory perception of a user (e.g., an “up click,” a “down click,” “roughness”), unless otherwise stated, the generated tactile output corresponds to physical displacement of the device or a component thereof that will generate the described sensory perception for a typical (or average) user. 
     It should be appreciated that device  100  is only one example of a portable multifunction device, and that device  100  optionally has more or fewer components than shown, optionally combines two or more components, or optionally has a different configuration or arrangement of the components. The various components shown in  FIG.  1 A  are implemented in hardware, software, or a combination of both hardware and software, including one or more signal processing and/or application specific integrated circuits. 
     Memory  102  may include one or more computer readable storage mediums. The computer readable storage mediums may be tangible and non-transitory. Memory  102  may include high-speed random access memory and may also include non-volatile memory, such as one or more magnetic disk storage devices, flash memory devices, or other non-volatile solid-state memory devices. Memory controller  122  may control access to memory  102  by other components of device  100 . 
     Peripherals interface  118  can be used to couple input and output peripherals of the device to CPU  120  and memory  102 . The one or more processors  120  run or execute various software programs and/or sets of instructions stored in memory  102  to perform various functions for device  100  and to process data. In some embodiments, peripherals interface  118 , CPU  120 , and memory controller  122  may be implemented on a single chip, such as chip  104 . In some other embodiments, they may be implemented on separate chips. 
     RF (radio frequency) circuitry  108  receives and sends RF signals, also called electromagnetic signals. RF circuitry  108  converts electrical signals to/from electromagnetic signals and communicates with communications networks and other communications devices via the electromagnetic signals. RF circuitry  108  optionally includes well-known circuitry for performing these functions, including but not limited to an antenna system, an RF transceiver, one or more amplifiers, a tuner, one or more oscillators, a digital signal processor, a CODEC chipset, a subscriber identity module (SIM) card, memory, and so forth. RF circuitry  108  optionally communicates with networks, such as the Internet, also referred to as the World Wide Web (WWW), an intranet and/or a wireless network, such as a cellular telephone network, a wireless local area network (LAN) and/or a metropolitan area network (MAN), and other devices by wireless communication. The wireless communication optionally uses any of a plurality of communications standards, protocols and technologies, including but not limited to Global System for Mobile Communications (GSM), Enhanced Data GSM Environment (EDGE), high-speed downlink packet access (HSDPA), high-speed uplink packet access (HSUPA), Evolution, Data-Only (EV-DO), HSPA, HSPA+, Dual-Cell HSPA (DC-HSPDA), long term evolution (LTE), near field communication (NFC), wideband code division multiple access (W-CDMA), code division multiple access (CDMA), time division multiple access (TDMA), Bluetooth, Bluetooth Low Energy (BTLE), Wireless Fidelity (Wi-Fi) (e.g., IEEE 802.11a, IEEE 802.11b, IEEE 802.11g and/or IEEE 802.11n), voice over Internet Protocol (VoIP), Wi-MAX, a protocol for e-mail (e.g., Internet message access protocol (IMAP) and/or post office protocol (POP)), instant messaging (e.g., extensible messaging and presence protocol (XMPP), Session Initiation Protocol for Instant Messaging and Presence Leveraging Extensions (SIMPLE), Instant Messaging and Presence Service (IMPS)), and/or Short Message Service (SMS), or any other suitable communication protocol, including communication protocols not yet developed as of the filing date of this document. 
     Audio circuitry  110 , speaker  111 , and microphone  113  provide an audio interface between a user and device  100 . Audio circuitry  110  receives audio data from peripherals interface  118 , converts the audio data to an electrical signal, and transmits the electrical signal to speaker  111 . Speaker  111  converts the electrical signal to human-audible sound waves. Audio circuitry  110  also receives electrical signals converted by microphone  113  from sound waves. Audio circuitry  110  converts the electrical signal to audio data and transmits the audio data to peripherals interface  118  for processing. Audio data may be retrieved from and/or transmitted to memory  102  and/or RF circuitry  108  by peripherals interface  118 . In some embodiments, audio circuitry  110  also includes a headset jack (e.g.,  212 ,  FIG.  2   ). The headset jack provides an interface between audio circuitry  110  and removable audio input/output peripherals, such as output-only headphones or a headset with both output (e.g., a headphone for one or both ears) and input (e.g., a microphone). 
     I/O subsystem  106  couples input/output peripherals on device  100 , such as touch screen  112  and other input control devices  116 , to peripherals interface  118 . I/O subsystem  106  optionally includes display controller  156 , optical sensor controller  158 , intensity sensor controller  159 , haptic feedback controller  161  and one or more input controllers  160  for other input or control devices. The one or more input controllers  160  receive/send electrical signals from/to other input or control devices  116 . The other input control devices  116  optionally include physical buttons (e.g., push buttons, rocker buttons, etc.), dials, slider switches, joysticks, click wheels, and so forth. In some alternate embodiments, input controller(s)  160  are, optionally, coupled to any (or none) of the following: a keyboard, infrared port, USB port, and a pointer device such as a mouse. The one or more buttons (e.g.,  208 ,  FIG.  2   ) optionally include an up/down button for volume control of speaker  111  and/or microphone  113 . The one or more buttons optionally include a push button (e.g.,  206 ,  FIG.  2   ). 
     A quick press of the push button may disengage a lock of touch screen  112  or begin a process that uses gestures on the touch screen to unlock the device, as described in U.S. patent application Ser. No. 11/322,549, “Unlocking a Device by Performing Gestures on an Unlock Image,” filed Dec. 23, 2005, U.S. Pat. No. 7,657,849, which is hereby incorporated by reference in its entirety. A longer press of the push button (e.g.,  206 ) may turn power to device  100  on or off. The user may be able to customize a functionality of one or more of the buttons. Touch screen  112  is used to implement virtual or soft buttons and one or more soft keyboards. 
     Touch-sensitive display  112  provides an input interface and an output interface between the device and a user. Display controller  156  receives and/or sends electrical signals from/to touch screen  112 . Touch screen  112  displays visual output to the user. The visual output may include graphics, text, icons, video, and any combination thereof (collectively termed “graphics”). In some embodiments, some or all of the visual output may correspond to user-interface objects. 
     Touch screen  112  has a touch-sensitive surface, sensor or set of sensors that accepts input from the user based on haptic and/or tactile contact. Touch screen  112  and display controller  156  (along with any associated modules and/or sets of instructions in memory  102 ) detect contact (and any movement or breaking of the contact) on touch screen  112  and converts the detected contact into interaction with user-interface objects (e.g., one or more soft keys, icons, web-pages or images) that are displayed on touch screen  112 . In an exemplary embodiment, a point of contact between touch screen  112  and the user corresponds to a finger of the user. 
     Touch screen  112  may use LCD (liquid crystal display) technology, LPD (light emitting polymer display) technology, or LED (light emitting diode) technology, although other display technologies may be used in other embodiments. Touch screen  112  and display controller  156  may detect contact and any movement or breaking thereof using any of a plurality of touch sensing technologies now known or later developed, including but not limited to capacitive, resistive, infrared, and surface acoustic wave technologies, as well as other proximity sensor arrays or other elements for determining one or more points of contact with touch screen  112 . In an exemplary embodiment, projected mutual capacitance sensing technology is used, such as that found in the iPhone® and iPod Touch® from Apple Inc. of Cupertino, Calif. 
     A touch-sensitive display in some embodiments of touch screen  112  may be analogous to the multi-touch sensitive touchpads described in the following U.S. Pat. No. 6,323,846 (Westerman et al.), U.S. Pat. No. 6,570,557 (Westerman et al.), and/or U.S. Pat. No. 6,677,932 (Westerman), and/or U.S. Patent Publication 2002/0015024A1, each of which is hereby incorporated by reference in its entirety. However, touch screen  112  displays visual output from device  100 , whereas touch sensitive touchpads do not provide visual output. 
     A touch-sensitive display in some embodiments of touch screen  112  may be as described in the following applications: (1) U.S. patent application Ser. No. 11/381,313, “Multipoint Touch Surface Controller,” filed May 2, 2006; (2) U.S. patent application Ser. No. 10/840,862, “Multipoint Touchscreen,” filed May 6, 2004; (3) U.S. patent application Ser. No. 10/903,964, “Gestures For Touch Sensitive Input Devices,” filed Jul. 30, 2004; (4) U.S. patent application Ser. No. 11/048,264, “Gestures For Touch Sensitive Input Devices,” filed Jan. 31, 2005; (5) U.S. patent application Ser. No. 11/038,590, “Mode-Based Graphical User Interfaces For Touch Sensitive Input Devices,” filed Jan. 18, 2005; (6) U.S. patent application Ser. No. 11/228,758, “Virtual Input Device Placement On A Touch Screen User Interface,” filed Sep. 16, 2005; (7) U.S. patent application Ser. No. 11/228,700, “Operation Of A Computer With A Touch Screen Interface,” filed Sep. 16, 2005; (8) U.S. patent application Ser. No. 11/228,737, “Activating Virtual Keys Of A Touch-Screen Virtual Keyboard,” filed Sep. 16, 2005; and (9) U.S. patent application Ser. No. 11/367,749, “Multi-Functional Hand-Held Device,” filed Mar. 3, 2006. All of these applications are incorporated by reference herein in their entirety. 
     Touch screen  112  may have a video resolution in excess of 100 dpi. In some embodiments, the touch screen has a video resolution of approximately 160 dpi. The user may make contact with touch screen  112  using any suitable object or appendage, such as a stylus, a finger, and so forth. In some embodiments, the user interface is designed to work primarily with finger-based contacts and gestures, which can be less precise than stylus-based input due to the larger area of contact of a finger on the touch screen. In some embodiments, the device translates the rough finger-based input into a precise pointer/cursor position or command for performing the actions desired by the user. 
     In some embodiments, in addition to the touch screen, device  100  may include a touchpad (not shown) for activating or deactivating particular functions. In some embodiments, the touchpad is a touch-sensitive area of the device that, unlike the touch screen, does not display visual output. The touchpad may be a touch-sensitive surface that is separate from touch screen  112  or an extension of the touch-sensitive surface formed by the touch screen. 
     Device  100  also includes power system  162  for powering the various components. Power system  162  may include a power management system, one or more power sources (e.g., battery, alternating current (AC)), a recharging system, a power failure detection circuit, a power converter or inverter, a power status indicator (e.g., a light-emitting diode (LED)) and any other components associated with the generation, management and distribution of power in portable devices. 
     Device  100  may also include one or more optical sensors  164 .  FIGS.  1 A and  1 B  show an optical sensor coupled to optical sensor controller  158  in I/O subsystem  106 . Optical sensor  164  may include charge-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) phototransistors. Optical sensor  164  receives light from the environment, projected through one or more lens, and converts the light to data representing an image. In conjunction with imaging module  143  (also called a camera module), optical sensor  164  may capture still images or video. In some embodiments, an optical sensor is located on the back of device  100 , opposite touch screen display  112  on the front of the device, so that the touch screen display may be used as a viewfinder for still and/or video image acquisition. In some embodiments, an optical sensor is located on the front of the device so that the user&#39;s image may be obtained for videoconferencing while the user views the other video conference participants on the touch screen display. In some embodiments, the position of optical sensor  164  can be changed by the user (e.g., by rotating the lens and the sensor in the device housing) so that a single optical sensor  164  may be used along with the touch screen display for both video conferencing and still and/or video image acquisition. 
     Device  100  optionally also includes one or more contact intensity sensors  165 .  FIG.  1 A  shows a contact intensity sensor coupled to intensity sensor controller  159  in I/O subsystem  106 . Contact intensity sensor  165  optionally includes one or more piezoresistive strain gauges, capacitive force sensors, electric force sensors, piezoelectric force sensors, optical force sensors, capacitive touch-sensitive surfaces, or other intensity sensors (e.g., sensors used to measure the force (or pressure) of a contact on a touch-sensitive surface). Contact intensity sensor  165  receives contact intensity information (e.g., pressure information or a proxy for pressure information) from the environment. In some embodiments, at least one contact intensity sensor is collocated with, or proximate to, a touch-sensitive surface (e.g., touch-sensitive display system  112 ). In some embodiments, at least one contact intensity sensor is located on the back of device  100 , opposite touch screen display  112  which is located on the front of device  100 . 
     Device  100  may also include one or more proximity sensors  166 .  FIGS.  1 A and  1 B  show proximity sensor  166  coupled to peripherals interface  118 . Alternately, proximity sensor  166  may be coupled to input controller  160  in I/O subsystem  106 . Proximity sensor  166  may perform as described in U.S. patent application Ser. No. 11/241,839, “Proximity Detector In Handheld Device”; Ser. No. 11/240,788, “Proximity Detector In Handheld Device”; Ser. No. 11/620,702, “Using Ambient Light Sensor To Augment Proximity Sensor Output”; Ser. No. 11/586,862, “Automated Response To And Sensing Of User Activity In Portable Devices”; and Ser. No. 11/638,251, “Methods And Systems For Automatic Configuration Of Peripherals,” which are hereby incorporated by reference in their entirety. In some embodiments, the proximity sensor turns off and disables touch screen  112  when the multifunction device is placed near the user&#39;s ear (e.g., when the user is making a phone call). 
     Device  100  optionally also includes one or more tactile output generators  167 .  FIG.  1 A  shows a tactile output generator coupled to haptic feedback controller  161  in I/O subsystem  106 . Tactile output generator  167  optionally includes one or more electroacoustic devices such as speakers or other audio components and/or electromechanical devices that convert energy into linear motion such as a motor, solenoid, electroactive polymer, piezoelectric actuator, electrostatic actuator, or other tactile output generating component (e.g., a component that converts electrical signals into tactile outputs on the device). Contact intensity sensor  165  receives tactile feedback generation instructions from haptic feedback module  133  and generates tactile outputs on device  100  that are capable of being sensed by a user of device  100 . In some embodiments, at least one tactile output generator is collocated with, or proximate to, a touch-sensitive surface (e.g., touch-sensitive display system  112 ) and, optionally, generates a tactile output by moving the touch-sensitive surface vertically (e.g., in/out of a surface of device  100 ) or laterally (e.g., back and forth in the same plane as a surface of device  100 ). In some embodiments, at least one tactile output generator sensor is located on the back of device  100 , opposite touch screen display  112  which is located on the front of device  100 . 
     Device  100  may also include one or more accelerometers  168 .  FIGS.  1 A and  1 B  show accelerometer  168  coupled to peripherals interface  118 . Alternately, accelerometer  168  may be coupled to an input controller  160  in I/O subsystem  106 . Accelerometer  168  may perform as described in U.S. Patent Publication No. 20050190059, “Acceleration-based Theft Detection System for Portable Electronic Devices,” and U.S. Patent Publication No. 20060017692, “Methods And Apparatuses For Operating A Portable Device Based On An Accelerometer,” both of which are which are incorporated by reference herein in their entirety. In some embodiments, information is displayed on the touch screen display in a portrait view or a landscape view based on an analysis of data received from the one or more accelerometers. Device  100  optionally includes, in addition to accelerometer(s)  168 , a magnetometer (not shown) and a GPS (or GLONASS or other global navigation system) receiver (not shown) for obtaining information concerning the location and orientation (e.g., portrait or landscape) of device  100 . 
     In some embodiments, the software components stored in memory  102  include operating system  126 , communication module (or set of instructions)  128 , contact/motion module (or set of instructions)  130 , graphics module (or set of instructions)  132 , text input module (or set of instructions)  134 , Global Positioning System (GPS) module (or set of instructions)  135 , and applications (or sets of instructions)  136 . Furthermore, in some embodiments memory  102  stores device/global internal state  157 , as shown in  FIGS.  1 A,  1 B and  3   . Device/global internal state  157  includes one or more of: active application state, indicating which applications, if any, are currently active; display state, indicating what applications, views or other information occupy various regions of touch screen display  112 ; sensor state, including information obtained from the device&#39;s various sensors and input control devices  116 ; and location information concerning the device&#39;s location and/or attitude. 
     Operating system  126  (e.g., Darwin, RTXC, LINUX, UNIX, OS X, iOS, WINDOWS, or an embedded operating system such as VxWorks) includes various software components and/or drivers for controlling and managing general system tasks (e.g., memory management, storage device control, power management, etc.) and facilitates communication between various hardware and software components. 
     Communication module  128  facilitates communication with other devices over one or more external ports  124  and also includes various software components for handling data received by RF circuitry  108  and/or external port  124 . External port  124  (e.g., Universal Serial Bus (USB), FIREWIRE, etc.) is adapted for coupling directly to other devices or indirectly over a network (e.g., the Internet, wireless LAN, etc.). In some embodiments, the external port is a multi-pin (e.g., 30-pin) connector that is the same as, or similar to and/or compatible with the 30-pin connector used on iPod® (trademark of Apple Inc.) devices. 
     Contact/motion module  130  optionally detects contact with touch screen  112  (in conjunction with display controller  156 ) and other touch sensitive devices (e.g., a touchpad or physical click wheel). Contact/motion module  130  includes various software components for performing various operations related to detection of contact, such as determining if contact has occurred (e.g., detecting a finger-down event), determining an intensity of the contact determining if there is movement of the contact and tracking the movement across the touch-sensitive surface (e.g., detecting one or more finger-dragging events), and determining if the contact has ceased (e.g., detecting a finger-up event or a break in contact). Contact/motion module  130  receives contact data from the touch-sensitive surface. Determining movement of the point of contact, which is represented by a series of contact data, optionally includes determining speed (magnitude), velocity (magnitude and direction), and/or an acceleration (a change in magnitude and/or direction) of the point of contact. These operations are, optionally, applied to single contacts (e.g., one finger contacts) or to multiple simultaneous contacts (e.g., “multitouch”/multiple finger contacts). In some embodiments, contact/motion module  130  and display controller  156  detect contact on a touchpad. 
     In some embodiments, contact/motion module  130  uses a set of one or more intensity thresholds to determine whether an operation has been performed by a user (e.g., to determine whether a user has “clicked” on an icon). In some embodiments at least a subset of the intensity thresholds are determined in accordance with software parameters (e.g., the intensity thresholds are not determined by the activation thresholds of particular physical actuators and can be adjusted without changing the physical hardware of device  100 ). For example, a mouse “click” threshold of a trackpad or touch screen display can be set to any of a large range of predefined thresholds values without changing the trackpad or touch screen display hardware. Additionally, in some implementations a user of the device is provided with software settings for adjusting one or more of the set of intensity thresholds (e.g., by adjusting individual intensity thresholds and/or by adjusting a plurality of intensity thresholds at once with a system-level click “intensity” parameter). 
     Contact/motion module  130  optionally detects a gesture input by a user. Different gestures on the touch-sensitive surface have different contact patterns (e.g., different motions, timings, and/or intensities of detected contacts). Thus, a gesture is, optionally, detected by detecting a particular contact pattern. For example, detecting a finger tap gesture includes detecting a finger-down event followed by detecting a finger-up (lift off) event at the same position (or substantially the same position) as the finger-down event (e.g., at the position of an icon). As another example, detecting a finger swipe gesture on the touch-sensitive surface includes detecting a finger-down event followed by detecting one or more finger-dragging events, and subsequently followed by detecting a finger-up (lift off) event. 
     Graphics module  132  includes various known software components for rendering and displaying graphics on touch screen  112  or other display, including components for changing the visual impact (e.g., brightness, transparency, saturation, contrast or other visual property) of graphics that are displayed. As used herein, the term “graphics” includes any object that can be displayed to a user, including without limitation text, web pages, icons (such as user-interface objects including soft keys), digital images, videos, animations and the like. 
     In some embodiments, graphics module  132  stores data representing graphics to be used. Each graphic is, optionally, assigned a corresponding code. Graphics module  132  receives, from applications etc., one or more codes specifying graphics to be displayed along with, if necessary, coordinate data and other graphic property data, and then generates screen image data to output to display controller  156 . 
     Haptic feedback module  133  includes various software components for generating instructions used by tactile output generator(s)  167  to produce tactile outputs at one or more locations on device  100  in response to user interactions with device  100 . 
     Text input module  134 , which may be a component of graphics module  132 , provides soft keyboards for entering text in various applications (e.g., contacts  137 , e-mail  140 , IM  141 , browser  147 , and any other application that needs text input). 
     GPS module  135  determines the location of the device and provides this information for use in various applications (e.g., to telephone  138  for use in location-based dialing, to camera  143  as picture/video metadata, and to applications that provide location-based services such as weather widgets, local yellow page widgets, and map/navigation widgets). 
     Applications  136  may include the following modules (or sets of instructions), or a subset or superset thereof:
         contacts module  137  (sometimes called an address book or contact list);   telephone module  138 ;   video conferencing module  139 ;   e-mail client module  140 ;   instant messaging (IM) module  141 ;   workout support module  142 ;   camera module  143  for still and/or video images;   image management module  144 ;   video player module  145 ;   music player module  146 ;   browser module  147 ;   calendar module  148 ;   widget modules  149 , which may include one or more of: weather widget  149 - 1 , stocks widget  149 - 2 , calculator widget  149 - 3 , alarm clock widget  149 - 4 , dictionary widget  149 - 5 , and other widgets obtained by the user, as well as user-created widgets  149 - 6 ;   widget creator module  150  for making user-created widgets  149 - 6 ;   search module  151 ;   video and music player module  152 , which merges video player module  145  and music player module  146 ;   notes module  153 ;   map module  154 ; and/or   online video module  155 .       

     Examples of other applications  136  that may be stored in memory  102  include other word processing applications, other image editing applications, drawing applications, presentation applications, JAVA-enabled applications, encryption, digital rights management, voice recognition, and voice replication. 
     In conjunction with touch screen  112 , display controller  156 , contact module  130 , graphics module  132 , and text input module  134 , contacts module  137  may be used to manage an address book or contact list (e.g., stored in application internal state  192  of contacts module  137  in memory  102  or memory  370 ), including: adding name(s) to the address book; deleting name(s) from the address book; associating telephone number(s), e-mail address(es), physical address(es) or other information with a name; associating an image with a name; categorizing and sorting names; providing telephone numbers or e-mail addresses to initiate and/or facilitate communications by telephone  138 , video conference  139 , e-mail  140 , or IM  141 ; and so forth. 
     In conjunction with RF circuitry  108 , audio circuitry  110 , speaker  111 , microphone  113 , touch screen  112 , display controller  156 , contact module  130 , graphics module  132 , and text input module  134 , telephone module  138  may be used to enter a sequence of characters corresponding to a telephone number, access one or more telephone numbers in address book  137 , modify a telephone number that has been entered, dial a respective telephone number, conduct a conversation and disconnect or hang up when the conversation is completed. As noted above, the wireless communication may use any of a plurality of communications standards, protocols and technologies. 
     In conjunction with RF circuitry  108 , audio circuitry  110 , speaker  111 , microphone  113 , touch screen  112 , display controller  156 , optical sensor  164 , optical sensor controller  158 , contact module  130 , graphics module  132 , text input module  134 , contact list  137 , and telephone module  138 , videoconferencing module  139  includes executable instructions to initiate, conduct, and terminate a video conference between a user and one or more other participants in accordance with user instructions. 
     In conjunction with RF circuitry  108 , touch screen  112 , display controller  156 , contact module  130 , graphics module  132 , and text input module  134 , e-mail client module  140  includes executable instructions to create, send, receive, and manage e-mail in response to user instructions. In conjunction with image management module  144 , e-mail client module  140  makes it very easy to create and send e-mails with still or video images taken with camera module  143 . 
     In conjunction with RF circuitry  108 , touch screen  112 , display controller  156 , contact module  130 , graphics module  132 , and text input module  134 , the instant messaging module  141  includes executable instructions to enter a sequence of characters corresponding to an instant message, to modify previously entered characters, to transmit a respective instant message (for example, using a Short Message Service (SMS) or Multimedia Message Service (MMS) protocol for telephony-based instant messages or using XMPP, SIMPLE, or IMPS for Internet-based instant messages), to receive instant messages and to view received instant messages. In some embodiments, transmitted and/or received instant messages may include graphics, photos, audio files, video files and/or other attachments as are supported in a MMS and/or an Enhanced Messaging Service (EMS). As used herein, “instant messaging” refers to both telephony-based messages (e.g., messages sent using SMS or MMS) and Internet-based messages (e.g., messages sent using XMPP, SIMPLE, or IMPS). 
     In conjunction with RF circuitry  108 , touch screen  112 , display controller  156 , contact module  130 , graphics module  132 , text input module  134 , GPS module  135 , map module  154 , and music player module  146 , workout support module  142  includes executable instructions to create workouts (e.g., with time, distance, and/or calorie burning goals); communicate with workout sensors (sports devices); receive workout sensor data; calibrate sensors used to monitor a workout; select and play music for a workout; and display, store and transmit workout data. 
     In conjunction with touch screen  112 , display controller  156 , optical sensor(s)  164 , optical sensor controller  158 , contact module  130 , graphics module  132 , and image management module  144 , camera module  143  includes executable instructions to capture still images or video (including a video stream) and store them into memory  102 , modify characteristics of a still image or video, or delete a still image or video from memory  102 . 
     In conjunction with touch screen  112 , display controller  156 , contact module  130 , graphics module  132 , text input module  134 , and camera module  143 , image management module  144  includes executable instructions to arrange, modify (e.g., edit), or otherwise manipulate, label, delete, present (e.g., in a digital slide show or album), and store still and/or video images. 
     In conjunction with RF circuitry  108 , touch screen  112 , display system controller  156 , contact module  130 , graphics module  132 , and text input module  134 , browser module  147  includes executable instructions to browse the Internet in accordance with user instructions, including searching, linking to, receiving, and displaying web-pages or portions thereof, as well as attachments and other files linked to web-pages. 
     In conjunction with RF circuitry  108 , touch screen  112 , display system controller  156 , contact module  130 , graphics module  132 , text input module  134 , e-mail client module  140 , and browser module  147 , calendar module  148  includes executable instructions to create, display, modify, and store calendars and data associated with calendars (e.g., calendar entries, to do lists, etc.) in accordance with user instructions. 
     In conjunction with RF circuitry  108 , touch screen  112 , display system controller  156 , contact module  130 , graphics module  132 , text input module  134 , and browser module  147 , widget modules  149  are mini-applications that may be downloaded and used by a user (e.g., weather widget  149 - 1 , stocks widget  149 - 2 , calculator widget  149 - 3 , alarm clock widget  149 - 4 , and dictionary widget  149 - 5 ) or created by the user (e.g., user-created widget  149 - 6 ). In some embodiments, a widget includes an HTML (Hypertext Markup Language) file, a CSS (Cascading Style Sheets) file, and a JavaScript file. In some embodiments, a widget includes an XML (Extensible Markup Language) file and a JavaScript file (e.g., Yahoo! Widgets). 
     In conjunction with RF circuitry  108 , touch screen  112 , display system controller  156 , contact module  130 , graphics module  132 , text input module  134 , and browser module  147 , the widget creator module  150  may be used by a user to create widgets (e.g., turning a user-specified portion of a web-page into a widget). 
     In conjunction with touch screen  112 , display system controller  156 , contact module  130 , graphics module  132 , and text input module  134 , search module  151  includes executable instructions to search for text, music, sound, image, video, and/or other files in memory  102  that match one or more search criteria (e.g., one or more user-specified search terms) in accordance with user instructions. 
     In conjunction with touch screen  112 , display system controller  156 , contact module  130 , graphics module  132 , audio circuitry  110 , speaker  111 , RF circuitry  108 , and browser module  147 , video and music player module  152  includes executable instructions that allow the user to download and play back recorded music and other sound files stored in one or more file formats, such as MP3 or AAC files, and executable instructions to display, present or otherwise play back videos (e.g., on touch screen  112  or on an external, connected display via external port  124 ). In some embodiments, device  100  optionally includes the functionality of an MP3 player, such as an iPod (trademark of Apple Inc.). 
     In conjunction with touch screen  112 , display controller  156 , contact module  130 , graphics module  132 , and text input module  134 , notes module  153  includes executable instructions to create and manage notes, to do lists, and the like in accordance with user instructions. 
     In conjunction with RF circuitry  108 , touch screen  112 , display system controller  156 , contact module  130 , graphics module  132 , text input module  134 , GPS module  135 , and browser module  147 , map module  154  may be used to receive, display, modify, and store maps and data associated with maps (e.g., driving directions; data on stores and other points of interest at or near a particular location; and other location-based data) in accordance with user instructions. 
     In conjunction with touch screen  112 , display system controller  156 , contact module  130 , graphics module  132 , audio circuitry  110 , speaker  111 , RF circuitry  108 , text input module  134 , e-mail client module  140 , and browser module  147 , online video module  155  includes instructions that allow the user to access, browse, receive (e.g., by streaming and/or download), play back (e.g., on the touch screen or on an external, connected display via external port  124 ), send an e-mail with a link to a particular online video, and otherwise manage online videos in one or more file formats, such as H.264. In some embodiments, instant messaging module  141 , rather than e-mail client module  140 , is used to send a link to a particular online video. Additional description of the online video application can be found in U.S. Provisional Patent Application No. 60/936,562, “Portable Multifunction Device, Method, and Graphical User Interface for Playing Online Videos,” filed Jun. 20, 2007, and U.S. patent application Ser. No. 11/968,067, “Portable Multifunction Device, Method, and Graphical User Interface for Playing Online Videos,” filed Dec. 31, 2007, the content of which is hereby incorporated by reference in its entirety. 
     Each of the above identified modules and applications correspond to a set of executable instructions for performing one or more functions described above and the methods described in this application (e.g., the computer-implemented methods and other information processing methods described herein). These modules (i.e., sets of instructions) need not be implemented as separate software programs, procedures or modules, and thus various subsets of these modules may be combined or otherwise re-arranged in various embodiments. For example, video player module  145  may be combined with music player module  146  into a single module (e.g., video and music player module  152 ,  FIG.  1 A ). In some embodiments, memory  102  may store a subset of the modules and data structures identified above. Furthermore, memory  102  may store additional modules and data structures not described above. 
     In some embodiments, device  100  is a device where operation of a predefined set of functions on the device is performed exclusively through a touch screen and/or a touchpad. By using a touch screen and/or a touchpad as the primary input control device for operation of device  100 , the number of physical input control devices (such as push buttons, dials, and the like) on device  100  may be reduced. 
     The predefined set of functions that are performed exclusively through a touch screen and/or a touchpad optionally include navigation between user interfaces. In some embodiments, the touchpad, when touched by the user, navigates device  100  to a main, home, or root menu from any user interface that is displayed on device  100 . In such embodiments, a “menu button” is implemented using a touchpad. In some other embodiments, the menu button is a physical push button or other physical input control device instead of a touchpad. 
       FIG.  1 B  is a block diagram illustrating exemplary components for event handling in accordance with some embodiments. In some embodiments, memory  102  (in  FIG.  1 A ) or  370  ( FIG.  3   ) includes event sorter  170  (e.g., in operating system  126 ) and a respective application  136 - 1  (e.g., any of the aforementioned applications  137 - 151 ,  155 ,  380 - 390 ). 
     Event sorter  170  receives event information and determines the application  136 - 1  and application view  191  of application  136 - 1  to which to deliver the event information. Event sorter  170  includes event monitor  171  and event dispatcher module  174 . In some embodiments, application  136 - 1  includes application internal state  192 , which indicates the current application view(s) displayed on touch sensitive display  112  when the application is active or executing. In some embodiments, device/global internal state  157  is used by event sorter  170  to determine which application(s) is (are) currently active, and application internal state  192  is used by event sorter  170  to determine application views  191  to which to deliver event information. 
     In some embodiments, application internal state  192  includes additional information, such as one or more of: resume information to be used when application  136 - 1  resumes execution, user interface state information that indicates information being displayed or that is ready for display by application  136 - 1 , a state queue for enabling the user to go back to a prior state or view of application  136 - 1 , and a redo/undo queue of previous actions taken by the user. 
     Event monitor  171  receives event information from peripherals interface  118 . Event information includes information about a sub-event (e.g., a user touch on touch-sensitive display  112 , as part of a multi-touch gesture). Peripherals interface  118  transmits information it receives from I/O subsystem  106  or a sensor, such as proximity sensor  166 , accelerometer(s)  168 , and/or microphone  113  (through audio circuitry  110 ). Information that peripherals interface  118  receives from I/O subsystem  106  includes information from touch-sensitive display  112  or a touch-sensitive surface. 
     In some embodiments, event monitor  171  sends requests to the peripherals interface  118  at predetermined intervals. In response, peripherals interface  118  transmits event information. In other embodiments, peripheral interface  118  transmits event information only when there is a significant event (e.g., receiving an input above a predetermined noise threshold and/or for more than a predetermined duration). 
     In some embodiments, event sorter  170  also includes a hit view determination module  172  and/or an active event recognizer determination module  173 . 
     Hit view determination module  172  provides software procedures for determining where a sub-event has taken place within one or more views, when touch sensitive display  112  displays more than one view. Views are made up of controls and other elements that a user can see on the display. 
     Another aspect of the user interface associated with an application is a set of views, sometimes herein called application views or user interface windows, in which information is displayed and touch-based gestures occur. The application views (of a respective application) in which a touch is detected may correspond to programmatic levels within a programmatic or view hierarchy of the application. For example, the lowest level view in which a touch is detected may be called the hit view, and the set of events that are recognized as proper inputs may be determined based, at least in part, on the hit view of the initial touch that begins a touch-based gesture. 
     Hit view determination module  172  receives information related to sub-events of a touch-based gesture. When an application has multiple views organized in a hierarchy, hit view determination module  172  identifies a hit view as the lowest view in the hierarchy which should handle the sub-event. In most circumstances, the hit view is the lowest level view in which an initiating sub-event occurs (i.e., the first sub-event in the sequence of sub-events that form an event or potential event). Once the hit view is identified by the hit view determination module, the hit view typically receives all sub-events related to the same touch or input source for which it was identified as the hit view. 
     Active event recognizer determination module  173  determines which view or views within a view hierarchy should receive a particular sequence of sub-events. In some embodiments, active event recognizer determination module  173  determines that only the hit view should receive a particular sequence of sub-events. In other embodiments, active event recognizer determination module  173  determines that all views that include the physical location of a sub-event are actively involved views, and therefore determines that all actively involved views should receive a particular sequence of sub-events. In other embodiments, even if touch sub-events were entirely confined to the area associated with one particular view, views higher in the hierarchy would still remain as actively involved views. 
     Event dispatcher module  174  dispatches the event information to an event recognizer (e.g., event recognizer  180 ). In embodiments including active event recognizer determination module  173 , event dispatcher module  174  delivers the event information to an event recognizer determined by active event recognizer determination module  173 . In some embodiments, event dispatcher module  174  stores in an event queue the event information, which is retrieved by a respective event receiver module  182 . 
     In some embodiments, operating system  126  includes event sorter  170 . Alternatively, application  136 - 1  includes event sorter  170 . In yet other embodiments, event sorter  170  is a stand-alone module, or a part of another module stored in memory  102 , such as contact/motion module  130 . 
     In some embodiments, application  136 - 1  includes a plurality of event handlers  190  and one or more application views  191 , each of which includes instructions for handling touch events that occur within a respective view of the application&#39;s user interface. Each application view  191  of the application  136 - 1  includes one or more event recognizers  180 . Typically, a respective application view  191  includes a plurality of event recognizers  180 . In other embodiments, one or more of event recognizers  180  are part of a separate module, such as a user interface kit (not shown) or a higher level object from which application  136 - 1  inherits methods and other properties. In some embodiments, a respective event handler  190  includes one or more of: data updater  176 , object updater  177 , GUI updater  178 , and/or event data  179  received from event sorter  170 . Event handler  190  may utilize or call data updater  176 , object updater  177  or GUI updater  178  to update the application internal state  192 . Alternatively, one or more of the application views  191  includes one or more respective event handlers  190 . Also, in some embodiments, one or more of data updater  176 , object updater  177 , and GUI updater  178  are included in a respective application view  191 . 
     A respective event recognizer  180  receives event information (e.g., event data  179 ) from event sorter  170 , and identifies an event from the event information. Event recognizer  180  includes event receiver  182  and event comparator  184 . In some embodiments, event recognizer  180  also includes at least a subset of: metadata  183 , and event delivery instructions  188  (which may include sub-event delivery instructions). 
     Event receiver  182  receives event information from event sorter  170 . The event information includes information about a sub-event, for example, a touch or a touch movement. Depending on the sub-event, the event information also includes additional information, such as location of the sub-event. When the sub-event concerns motion of a touch the event information may also include speed and direction of the sub-event. In some embodiments, events include rotation of the device from one orientation to another (e.g., from a portrait orientation to a landscape orientation, or vice versa), and the event information includes corresponding information about the current orientation (also called device attitude) of the device. 
     Event comparator  184  compares the event information to predefined event or sub-event definitions and, based on the comparison, determines an event or sub-event, or determines or updates the state of an event or sub-event. In some embodiments, event comparator  184  includes event definitions  186 . Event definitions  186  contain definitions of events (e.g., predefined sequences of sub-events), for example, event  1  ( 187 - 1 ), event  2  ( 187 - 2 ), and others. In some embodiments, sub-events in an event ( 187 ) include, for example, touch begin, touch end, touch movement, touch cancellation, and multiple touching. In one example, the definition for event  1  ( 187 - 1 ) is a double tap on a displayed object. The double tap, for example, comprises a first touch (touch begin) on the displayed object for a predetermined phase, a first lift-off (touch end) for a predetermined phase, a second touch (touch begin) on the displayed object for a predetermined phase, and a second lift-off (touch end) for a predetermined phase. In another example, the definition for event  2  ( 187 - 2 ) is a dragging on a displayed object. The dragging, for example, comprises a touch (or contact) on the displayed object for a predetermined phase, a movement of the touch across touch-sensitive display  112 , and lift-off of the touch (touch end). In some embodiments, the event also includes information for one or more associated event handlers  190 . 
     In some embodiments, event definition  187  includes a definition of an event for a respective user-interface object. In some embodiments, event comparator  184  performs a hit test to determine which user-interface object is associated with a sub-event. For example, in an application view in which three user-interface objects are displayed on touch-sensitive display  112 , when a touch is detected on touch-sensitive display  112 , event comparator  184  performs a hit test to determine which of the three user-interface objects is associated with the touch (sub-event). If each displayed object is associated with a respective event handler  190 , the event comparator uses the result of the hit test to determine which event handler  190  should be activated. For example, event comparator  184  selects an event handler associated with the sub-event and the object triggering the hit test. 
     In some embodiments, the definition for a respective event ( 187 ) also includes delayed actions that delay delivery of the event information until after it has been determined whether the sequence of sub-events does or does not correspond to the event recognizer&#39;s event type. 
     When a respective event recognizer  180  determines that the series of sub-events do not match any of the events in event definitions  186 , the respective event recognizer  180  enters an event impossible, event failed, or event ended state, after which it disregards subsequent sub-events of the touch-based gesture. In this situation, other event recognizers, if any, that remain active for the hit view continue to track and process sub-events of an ongoing touch-based gesture. 
     In some embodiments, a respective event recognizer  180  includes metadata  183  with configurable properties, flags, and/or lists that indicate how the event delivery system should perform sub-event delivery to actively involved event recognizers. In some embodiments, metadata  183  includes configurable properties, flags, and/or lists that indicate how event recognizers may interact, or are enabled to interact, with one another. In some embodiments, metadata  183  includes configurable properties, flags, and/or lists that indicate whether sub-events are delivered to varying levels in the view or programmatic hierarchy. 
     In some embodiments, a respective event recognizer  180  activates event handler  190  associated with an event when one or more particular sub-events of an event are recognized. In some embodiments, a respective event recognizer  180  delivers event information associated with the event to event handler  190 . Activating an event handler  190  is distinct from sending (and deferred sending) sub-events to a respective hit view. In some embodiments, event recognizer  180  throws a flag associated with the recognized event, and event handler  190  associated with the flag catches the flag and performs a predefined process. 
     In some embodiments, event delivery instructions  188  include sub-event delivery instructions that deliver event information about a sub-event without activating an event handler. Instead, the sub-event delivery instructions deliver event information to event handlers associated with the series of sub-events or to actively involved views. Event handlers associated with the series of sub-events or with actively involved views receive the event information and perform a predetermined process. 
     In some embodiments, data updater  176  creates and updates data used in application  136 - 1 . For example, data updater  176  updates the telephone number used in contacts module  137 , or stores a video file used in video player module  145 . In some embodiments, object updater  177  creates and updates objects used in application  136 - 1 . For example, object updater  176  creates a new user-interface object or updates the position of a user-interface object. GUI updater  178  updates the GUI. For example, GUI updater  178  prepares display information and sends it to graphics module  132  for display on a touch-sensitive display. 
     In some embodiments, event handler(s)  190  includes or has access to data updater  176 , object updater  177 , and GUI updater  178 . In some embodiments, data updater  176 , object updater  177 , and GUI updater  178  are included in a single module of a respective application  136 - 1  or application view  191 . In other embodiments, they are included in two or more software modules. 
     It shall be understood that the foregoing discussion regarding event handling of user touches on touch-sensitive displays also applies to other forms of user inputs to operate multifunction devices  100  with input-devices, not all of which are initiated on touch screens. For example, mouse movement and mouse button presses, optionally coordinated with single or multiple keyboard presses or holds; contact movements such as taps, drags, scrolls, etc., on touch-pads; pen stylus inputs; movement of the device; oral instructions; detected eye movements; biometric inputs; and/or any combination thereof are optionally utilized as inputs corresponding to sub-events which define an event to be recognized. 
       FIG.  2    illustrates a portable multifunction device  100  having a touch screen  112  in accordance with some embodiments. The touch screen optionally displays one or more graphics within user interface (UI)  200 . In this embodiment, as well as others described below, a user is enabled to select one or more of the graphics by making a gesture on the graphics, for example, with one or more fingers  202  (not drawn to scale in the figure) or one or more styluses  203  (not drawn to scale in the figure). In some embodiments, selection of one or more graphics occurs when the user breaks contact with the one or more graphics. In some embodiments, the gesture optionally includes one or more taps, one or more swipes (from left to right, right to left, upward and/or downward) and/or a rolling of a finger (from right to left, left to right, upward and/or downward) that has made contact with device  100 . In some implementations or circumstances, inadvertent contact with a graphic does not select the graphic. For example, a swipe gesture that sweeps over an application icon optionally does not select the corresponding application when the gesture corresponding to selection is a tap. 
     Device  100  may also include one or more physical buttons, such as “home” or menu button  204 . As described previously, menu button  204  may be used to navigate to any application  136  in a set of applications that may be executed on device  100 . Alternatively, in some embodiments, the menu button is implemented as a soft key in a GUI displayed on touch screen  112 . 
     In one embodiment, device  100  includes touch screen  112 , menu button  204 , push button  206  for powering the device on/off and locking the device, volume adjustment button(s)  208 , Subscriber Identity Module (SIM) card slot  210 , head set jack  212 , and docking/charging external port  124 . Push button  206  is, optionally, used to turn the power on/off on the device by depressing the button and holding the button in the depressed state for a predefined time interval; to lock the device by depressing the button and releasing the button before the predefined time interval has elapsed; and/or to unlock the device or initiate an unlock process. In an alternative embodiment, device  100  also accepts verbal input for activation or deactivation of some functions through microphone  113 . Device  100  also, optionally, includes one or more contact intensity sensors  165  for detecting intensity of contacts on touch screen  112  and/or one or more tactile output generators  167  for generating tactile outputs for a user of device  100 . 
       FIG.  3    is a block diagram of an exemplary multifunction device with a display and a touch-sensitive surface in accordance with some embodiments. Device  300  need not be portable. In some embodiments, device  300  is a laptop computer, a desktop computer, a tablet computer, a multimedia player device, a navigation device, an educational device (such as a child&#39;s learning toy), a gaming system, or a control device (e.g., a home or industrial controller). Device  300  typically includes one or more processing units (CPU&#39;s)  310 , one or more network or other communications interfaces  360 , memory  370 , and one or more communication buses  320  for interconnecting these components. Communication buses  320  optionally include circuitry (sometimes called a chipset) that interconnects and controls communications between system components. Device  300  includes input/output (I/O) interface  330  comprising display  340 , which is typically a touch screen display. I/O interface  330  also optionally includes a keyboard and/or mouse (or other pointing device)  350  and touchpad  355 , tactile output generator  357  for generating tactile outputs on device  300  (e.g., similar to tactile output generator(s)  167  described above with reference to  FIG.  1 A ), sensors  359  (e.g., optical, acceleration, proximity, touch-sensitive, and/or contact intensity sensors similar to contact intensity sensor(s)  165  described above with reference to  FIG.  1 A ). Memory  370  includes high-speed random access memory, such as DRAM, SRAM, DDR RAM or other random access solid state memory devices; and optionally includes non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. Memory  370  optionally includes one or more storage devices remotely located from CPU(s)  310 . In some embodiments, memory  370  stores programs, modules, and data structures analogous to the programs, modules, and data structures stored in memory  102  of portable multifunction device  100  ( FIG.  1 A ), or a subset thereof. Furthermore, memory  370  optionally stores additional programs, modules, and data structures not present in memory  102  of portable multifunction device  100 . For example, memory  370  of device  300  optionally stores drawing module  380 , presentation module  382 , word processing module  384 , website creation module  386 , disk authoring module  388 , and/or spreadsheet module  390 , while memory  102  of portable multifunction device  100  ( FIG.  1 A ) optionally does not store these modules. 
     Each of the above identified elements in  FIG.  3    may be stored in one or more of the previously mentioned memory devices. Each of the above identified modules corresponds to a set of instructions for performing a function described above. The above identified modules or programs (i.e., sets of instructions) need not be implemented as separate software programs, procedures or modules, and thus various subsets of these modules may be combined or otherwise re-arranged in various embodiments. In some embodiments, memory  370  may store a subset of the modules and data structures identified above. Furthermore, memory  370  may store additional modules and data structures not described above. 
     Attention is now directed towards embodiments of user interfaces (“UI”) that may be implemented on portable multifunction device  100 . 
       FIG.  4 A  illustrates an exemplary user interface for a menu of applications on portable multifunction device  100  in accordance with some embodiments. Similar user interfaces may be implemented on device  300 . In some embodiments, user interface  400  includes the following elements, or a subset or superset thereof:
         Signal strength indicator(s)  402  for wireless communication(s), such as cellular and Wi-Fi signals;   Time  404 ;   Bluetooth indicator  405 ;   Battery status indicator  406 ;   Tray  408  with icons for frequently used applications, such as:
           Icon  416  for telephone module  138 , labeled “Phone,” which optionally includes an indicator  414  of the number of missed calls or voicemail messages;   Icon  418  for e-mail client module  140 , labeled “Mail,” which optionally includes an indicator  410  of the number of unread e-mails;   Icon  420  for browser module  147 , labeled “Browser;” and   Icon  422  for video and music player module  152 , also referred to as iPod (trademark of Apple Inc.) module  152 , labeled “iPod;” and   
           Icons for other applications, such as:
           Icon  424  for IM module  141 , labeled “Messages;”   Icon  426  for calendar module  148 , labeled “Calendar;”   Icon  428  for image management module  144 , labeled “Photos;”   Icon  430  for camera module  143 , labeled “Camera;”   Icon  432  for online video module  155 , labeled “Online Video”   Icon  434  for stocks widget  149 - 2 , labeled “Stocks;”   Icon  436  for map module  154 , labeled “Map;”   Icon  438  for weather widget  149 - 1 , labeled “Weather;”   Icon  440  for alarm clock widget  149 - 4 , labeled “Clock;”   Icon  442  for workout support module  142 , labeled “Workout Support;”   Icon  444  for notes module  153 , labeled “Notes;” and   Icon  446  for a settings application or module, which provides access to settings for device  100  and its various applications  136 .   
               

     It should be noted that the icon labels illustrated in  FIG.  4 A  are merely exemplary. For example, icons  422  for video and music player module  152  are labeled “Music” or “Music Player.” Other labels are, optionally, used for various application icons. In some embodiments, a label for a respective application icon includes a name of an application corresponding to the respective application icon. In some embodiments, a label for a particular application icon is distinct from a name of an application corresponding to the particular application icon. 
       FIG.  4 B  illustrates an exemplary user interface on a device (e.g., device  300 ,  FIG.  3   ) with a touch-sensitive surface  451  (e.g., a tablet or touchpad  355 ,  FIG.  3   ) that is separate from the display  450  (e.g., touch screen display  112 ). Device  300  also, optionally, includes one or more contact intensity sensors (e.g., one or more of sensors  357 ) for detecting intensity of contacts on touch-sensitive surface  451  and/or one or more tactile output generators  359  for generating tactile outputs for a user of device  300 . 
     Although some of the examples which follow will be given with reference to inputs on touch screen display  112  (where the touch sensitive surface and the display are combined), in some embodiments, the device detects inputs on a touch-sensitive surface that is separate from the display, as shown in  FIG.  4 B . In some embodiments the touch sensitive surface (e.g.,  451  in  FIG.  4 B ) has a primary axis (e.g.,  452  in  FIG.  4 B ) that corresponds to a primary axis (e.g.,  453  in  FIG.  4 B ) on the display (e.g.,  450 ). In accordance with these embodiments, the device detects contacts (e.g.,  460  and  462  in  FIG.  4 B ) with the touch-sensitive surface  451  at locations that correspond to respective locations on the display (e.g., in  FIG.  4 B,  460    corresponds to  468  and  462  corresponds to  470 ). In this way, user inputs (e.g., contacts  460  and  462 , and movements thereof) detected by the device on the touch-sensitive surface (e.g.,  451  in  FIG.  4 B ) are used by the device to manipulate the user interface on the display (e.g.,  450  in  FIG.  4 B ) of the multifunction device when the touch-sensitive surface is separate from the display. It should be understood that similar methods are, optionally, used for other user interfaces described herein. 
     Additionally, while the following examples are given primarily with reference to finger inputs (e.g., finger contacts, finger tap gestures, finger swipe gestures), it should be understood that, in some embodiments, one or more of the finger inputs are replaced with input from another input device (e.g., a mouse based input or stylus input). For example, a swipe gesture is, optionally, replaced with a mouse click (e.g., instead of a contact) followed by movement of the cursor along the path of the swipe (e.g., instead of movement of the contact). As another example, a tap gesture is, optionally, replaced with a mouse click while the cursor is located over the location of the tap gesture (e.g., instead of detection of the contact followed by ceasing to detect the contact). Similarly, when multiple user inputs are simultaneously detected, it should be understood that multiple computer mice are, optionally, used simultaneously, or a mouse and finger contacts are, optionally, used simultaneously. 
       FIG.  5 A  illustrates exemplary personal electronic device  500 . Device  500  includes body  502 . In some embodiments, device  500  has touch-sensitive display screen  504 . Alternatively, or in addition to touchscreen  504 , device  500  has a display and a touch-sensitive surface. In some embodiments, touchscreen  504  (or the touch-sensitive surface) may have one or more intensity sensors for detecting intensity of contacts (e.g. touches) being applied. The one or more intensity sensors of touchscreen  504  (or the touch-sensitive surface) can provide output data that represents the intensity of touches. The user interface of device  500  can respond to touches based on their intensity, meaning that touches of different intensities can invoke different user interface operations on device  500 . 
     In some embodiments, regardless of whether touchscreen  504  (or the touch-sensitive surface) has the above-described intensity sensors, device  500  can optionally communicate with a stylus having a pressure-sensitive tip that detects and provides data regarding the intensity of the stylus&#39;s touch on device  500 , particularly touchscreen  504 . 
     Techniques for detecting and processing touch intensity may be found, for example, in related applications: International Patent Application Serial No. PCT/US2013/040061, entitled “Device, Method, and Graphical User Interface for Displaying User Interface Objects Corresponding to an Application,” filed May 8, 2013 and International Patent Application Serial No. PCT/US2013/069483, entitled “Device, Method, and Graphical User Interface for Transitioning Between Touch Input to Display Output Relationships,” filed Nov. 11, 2013. 
     In some embodiments, device  500  has one or more input mechanisms  506  and  508 . Input mechanisms  506  and  508 , if included, can be physical. Examples of physical input mechanisms include push buttons and rotatable mechanisms. In some embodiments, device  500  has one or more attachment mechanisms. Such attachment mechanisms, if included, can permit attachment of device  500  with, for example, hats, eyewear, earrings, necklaces, shirts, jackets, bracelets, watch straps, chains, trousers, belts, shoes, purses, backpacks, and so forth. These attachment mechanisms may permit device  500  to be worn by a user. 
       FIG.  5 B  depicts exemplary personal electronic device  500 . Device  500  has bus  512  that operatively couples I/O section  514  with one or more computer processors  516  and memory  518 . I/O section  514  can be connected to display  504 , which can have touch-sensitive component  522  and, optionally, touch-intensity sensitive component  524 . In addition, I/O section  514  can be connected with communication unit  530  for receiving application and operating system data, using Wi-Fi, Bluetooth™, near field communication (“NFC”), cellular and/or other wireless communication techniques. Device  500  can include input mechanisms  506  and/or  508 . Input mechanism  506  may be a rotatable input device, for example. Input mechanism  508  may be a button, in some examples. 
     Input mechanism  508  may be a microphone, in some examples. Computing device  500  can include various sensors, such as GPS sensor  532 , accelerometer  534 , directional sensor  540  (e.g., compass), gyroscope  536 , motion sensor  538 , and/or a combination thereof, all of which can be operatively connected to I/O section  514 . 
     Memory  518  of computing device  500  can be a non-transitory computer readable storage medium, for storing computer-executable instructions, which, when executed by one or more computer processors  516 , for example, can cause the computer processors to perform the techniques described above, including the processes of  FIGS.  7 ,  9 A,  9 B,  11 ,  13 K,  22 ,  31 ,  39 , and  46   . The computer-executable instructions can also be stored and/or transported within any non-transitory computer readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For purposes of this document, a “non-transitory computer readable storage medium” can be any medium that can tangibly contain or store computer-executable instructions for use by or in connection with the instruction execution system, apparatus, or device. The non-transitory computer readable storage medium can include, but is not limited to, magnetic, optical, and/or semiconductor storages. Examples of such storage include magnetic disks, optical discs based on CD, DVD, or Blu-ray technologies, as well as persistent solid-state memory such as flash, solid-state drives, and the like. Computing device  500  is not limited to the components and configuration of  FIG.  5 B , but can include other or additional components in multiple configurations. 
       FIG.  5 C  illustrates exemplary personal electronic device  550 . In the illustrated example, device  550  is a watch that generally includes body  552  and strap  554  for affixing device  550  to the body of a user. That is, device  550  is wearable. Body  552  can designed to couple with straps  554 . Device  550  can have touch-sensitive display screen (hereafter touchscreen)  556  and crown  558 . Device  550  can also have buttons  560 ,  562 , and  564 . 
     Conventionally, the term ‘crown,’ in the context of a watch, refers to the cap atop a stem for winding the watch. In the context of a personal electronic device, the crown can be a physical component of the electronic device, rather than a virtual crown on a touch sensitive display. Crown  558  can be mechanical, meaning that it can be connected to a sensor for converting physical movement of the crown into electrical signals. Crown  558  can rotate in two directions of rotation (e.g., forward and backward). Crown  558  can also be pushed in towards the body of device  550  and/or be pulled away from device  550 . Crown  558  can be touch-sensitive, for example, using capacitive touch technologies that can detect whether a user is touching the crown. Moreover, crown  558  can further be rocked in one or more directions or translated along a track along an edge or at least partially around a perimeter of body  552 . In some examples, more than one crown  558  can be used. The visual appearance of crown  558  can, but need not, resemble crowns of conventional watches. Buttons  560 ,  562 , and  564 , if included, can each be a physical or a touch-sensitive button. That is, the buttons may be, for example, physical buttons or capacitive buttons. Further, body  552 , which can include a bezel, may have predetermined regions on the bezel that act as buttons. 
     Display  556  can include a display device, such as a liquid crystal display (LCD), light-emitting diode (LED) display, organic light-emitting diode (OLED) display, or the like, positioned partially or fully behind or in front of a touch sensor panel implemented using any desired touch sensing technology, such as mutual-capacitance touch sensing, self-capacitance touch sensing, resistive touch sensing, projection scan touch sensing, or the like. Display  556  can allow a user to perform various functions by touching over hovering near the touch sensor panel using one or more fingers or other object. 
     In some examples, device  550  can further include one or more pressure sensors (not shown) for detecting a force or pressure applied to the display. The force or pressure applied to display  556  can be used as an input to device  550  to perform any desired operation, such as making a selection, entering or exiting a menu, causing the display of additional options/actions, or the like. In some examples, different operations can be performed based on the amount of force or pressure being applied to display  556 . The one or more pressure sensors can further be used to determine a position that the force is being applied to display  556 . 
       FIG.  5 D  illustrates a block diagram of some of the components of device  550 . As shown, crown  558  can be coupled to encoder  572 , which can be configured to monitor a physical state or change of state of crown  558  (e.g., the position of the crown), convert it to an electrical signal (e.g., convert it to an analog or digital signal representation of the position or change in position of crown  558 ), and provide the signal to processor  570 . For instance, in some examples, encoder  572  can be configured to sense the absolute rotational position (e.g., an angle between 0-360°) of crown  558  and output an analog or digital representation of this position to processor  570 . Alternatively, in other examples, encoder  572  can be configured to sense a change in rotational position (e.g., a change in rotational angle) of crown  558  over some sampling period and to output an analog or digital representation of the sensed change to processor  570 . In these examples, the crown position information can further indicate a direction of rotation of the crown (e.g., a positive value can correspond to one direction and a negative value can correspond to the other). In yet other examples, encoder  572  can be configured to detect a rotation of crown  558  in any desired manner (e.g., velocity, acceleration, or the like) and can provide the crown rotational information to processor  570 . In alternative examples, instead of providing information to processor  570 , this information can be provided to other components of device  550 . While the examples described herein refer to the use of rotational position of crown  558  to control scrolling, scaling, or an objects position, it should be appreciated that any other physical state of crown  558  can be used. 
     In some examples, the physical state of the crown can control physical attributes of display  556 . For example, if crown  558  is in a particular position (e.g., rotated forward), display  556  can have limited z-axis traversal ability. In other words, the physical state of the crown can represent physical modal functionality of display  556 . In some examples, a temporal attribute of the physical state of crown  558  can be used as an input to device  550 . For example, a fast change in physical state can be interpreted differently than a slow change in physical state. 
     Processor  570  can be further coupled to receive input signals from buttons  560 ,  562 , and  564 , along with touch signals from touch-sensitive display  556 . The buttons may be, for example, physical buttons or capacitive buttons. Further, body  552 , which can include a bezel, may have predetermined regions on the bezel that act as buttons. Processor  570  can be configured to interpret these input signals and output appropriate display signals to cause an image to be produced by touch-sensitive display  556 . While a single processor  570  is shown, it should be appreciated that any number of processors or other computational devices can be used to perform the general functions discussed above. 
     As used here, the term “affordance” refers to a user-interactive graphical user interface object that may be displayed on the display screen of device  100 ,  300 , and/or  500  ( FIGS.  1 ,  3 , and  5   ). For example, an image (e.g., icon), a button, and text (e.g., hyperlink) may each constitute an affordance. 
     As used herein, the term “focus selector” refers to an input element that indicates a current part of a user interface with which a user is interacting. In some implementations that include a cursor or other location marker, the cursor acts as a “focus selector,” so that when an input (e.g., a press input) is detected on a touch-sensitive surface (e.g., touchpad  355  in  FIG.  3    or touch-sensitive surface  451  in  FIG.  4 B ) while the cursor is over a particular user interface element (e.g., a button, window, slider or other user interface element), the particular user interface element is adjusted in accordance with the detected input. In some implementations that include a touch-screen display (e.g., touch-sensitive display system  112  in  FIG.  1 A  or touch screen  112  in  FIG.  4 A ) that enables direct interaction with user interface elements on the touch-screen display, a detected contact on the touch-screen acts as a “focus selector,” so that when an input (e.g., a press input by the contact) is detected on the touch-screen display at a location of a particular user interface element (e.g., a button, window, slider or other user interface element), the particular user interface element is adjusted in accordance with the detected input. In some implementations focus is moved from one region of a user interface to another region of the user interface without corresponding movement of a cursor or movement of a contact on a touch-screen display (e.g., by using a tab key or arrow keys to move focus from one button to another button); in these implementations, the focus selector moves in accordance with movement of focus between different regions of the user interface. Without regard to the specific form taken by the focus selector, the focus selector is generally the user interface element (or contact on a touch-screen display) that is controlled by the user so as to communicate the user&#39;s intended interaction with the user interface (e.g., by indicating, to the device, the element of the user interface with which the user is intending to interact). For example, the location of a focus selector (e.g., a cursor, a contact or a selection box) over a respective button while a press input is detected on the touch-sensitive surface (e.g., a touchpad or touch screen) will indicate that the user is intending to activate the respective button (as opposed to other user interface elements shown on a display of the device). 
     As used in the specification and claims, the term “characteristic intensity” of a contact refers to a characteristic of the contact based on one or more intensities of the contact. In some embodiments, the characteristic intensity is based on multiple intensity samples. The characteristic intensity is, optionally, based on a predefined number of intensity samples, or a set of intensity samples collected during a predetermined time period (e.g., 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10 seconds) relative to a predefined event (e.g., after detecting the contact, prior to detecting liftoff of the contact, before or after detecting a start of movement of the contact, prior to detecting an end of the contact, before or after detecting an increase in intensity of the contact, and/or before or after detecting a decrease in intensity of the contact). A characteristic intensity of a contact is, optionally based on one or more of: a maximum value of the intensities of the contact, a mean value of the intensities of the contact, an average value of the intensities of the contact, a top 10 percentile value of the intensities of the contact, a value at the half maximum of the intensities of the contact, a value at the 90 percent maximum of the intensities of the contact, or the like. In some embodiments, the duration of the contact is used in determining the characteristic intensity (e.g., when the characteristic intensity is an average of the intensity of the contact over time). In some embodiments, the characteristic intensity is compared to a set of one or more intensity thresholds to determine whether an operation has been performed by a user. For example, the set of one or more intensity thresholds may include a first intensity threshold and a second intensity threshold. In this example, a contact with a characteristic intensity that does not exceed the first threshold results in a first operation, a contact with a characteristic intensity that exceeds the first intensity threshold and does not exceed the second intensity threshold results in a second operation, and a contact with a characteristic intensity that exceeds the third threshold results in a third operation. In some embodiments, a comparison between the characteristic intensity and one or more thresholds is used to determine whether or not to perform one or more operations (e.g., whether to perform a respective option or forgo performing the respective operation) rather than being used to determine whether to perform a first operation or a second operation. 
     In some embodiments, a portion of a gesture is identified for purposes of determining a characteristic intensity. For example, a touch-sensitive surface may receive a continuous swipe contact transitioning from a start location and reaching an end location, at which point the intensity of the contact increases. In this example, the characteristic intensity of the contact at the end location may be based on only a portion of the continuous swipe contact, and not the entire swipe contact (e.g., only the portion of the swipe contact at the end location). In some embodiments, a smoothing algorithm may be applied to the intensities of the swipe contact prior to determining the characteristic intensity of the contact. For example, the smoothing algorithm optionally includes one or more of: an unweighted sliding-average smoothing algorithm, a triangular smoothing algorithm, a median filter smoothing algorithm, and/or an exponential smoothing algorithm. In some circumstances, these smoothing algorithms eliminate narrow spikes or dips in the intensities of the swipe contact for purposes of determining a characteristic intensity. 
     The intensity of a contact on the touch-sensitive surface may be characterized relative to one or more intensity thresholds, such as a contact-detection intensity threshold, a light press intensity threshold, a deep press intensity threshold, and/or one or more other intensity thresholds. In some embodiments, the light press intensity threshold corresponds to an intensity at which the device will perform operations typically associated with clicking a button of a physical mouse or a trackpad. In some embodiments, the deep press intensity threshold corresponds to an intensity at which the device will perform operations that are different from operations typically associated with clicking a button of a physical mouse or a trackpad. In some embodiments, when a contact is detected with a characteristic intensity below the light press intensity threshold (e.g., and above a nominal contact-detection intensity threshold below which the contact is no longer detected), the device will move a focus selector in accordance with movement of the contact on the touch-sensitive surface without performing an operation associated with the light press intensity threshold or the deep press intensity threshold. Generally, unless otherwise stated, these intensity thresholds are consistent between different sets of user interface figures. 
     An increase of characteristic intensity of the contact from an intensity below the light press intensity threshold to an intensity between the light press intensity threshold and the deep press intensity threshold is sometimes referred to as a “light press” input. An increase of characteristic intensity of the contact from an intensity below the deep press intensity threshold to an intensity above the deep press intensity threshold is sometimes referred to as a “deep press” input. An increase of characteristic intensity of the contact from an intensity below the contact-detection intensity threshold to an intensity between the contact-detection intensity threshold and the light press intensity threshold is sometimes referred to as detecting the contact on the touch-surface. A decrease of characteristic intensity of the contact from an intensity above the contact-detection intensity threshold to an intensity below the contact-detection intensity threshold is sometimes referred to as detecting liftoff of the contact from the touch-surface. In some embodiments the contact-detection intensity threshold is zero. In some embodiments the contact-detection intensity threshold is greater than zero. 
     In some embodiments described herein, one or more operations are performed in response to detecting a gesture that includes a respective press input or in response to detecting the respective press input performed with a respective contact (or a plurality of contacts), where the respective press input is detected based at least in part on detecting an increase in intensity of the contact (or plurality of contacts) above a press-input intensity threshold. In some embodiments, the respective operation is performed in response to detecting the increase in intensity of the respective contact above the press-input intensity threshold (e.g., a “down stroke” of the respective press input). In some embodiments, the press input includes an increase in intensity of the respective contact above the press-input intensity threshold and a subsequent decrease in intensity of the contact below the press-input intensity threshold, and the respective operation is performed in response to detecting the subsequent decrease in intensity of the respective contact below the press-input threshold (e.g., an “up stroke” of the respective press input). 
     In some embodiments, the device employs intensity hysteresis to avoid accidental inputs sometimes termed “jitter,” where the device defines or selects a hysteresis intensity threshold with a predefined relationship to the press-input intensity threshold (e.g., the hysteresis intensity threshold is X intensity units lower than the press-input intensity threshold or the hysteresis intensity threshold is 75%, 90% or some reasonable proportion of the press-input intensity threshold). Thus, in some embodiments, the press input includes an increase in intensity of the respective contact above the press-input intensity threshold and a subsequent decrease in intensity of the contact below the hysteresis intensity threshold that corresponds to the press-input intensity threshold, and the respective operation is performed in response to detecting the subsequent decrease in intensity of the respective contact below the hysteresis intensity threshold (e.g., an “up stroke” of the respective press input). Similarly, in some embodiments, the press input is detected only when the device detects an increase in intensity of the contact from an intensity at or below the hysteresis intensity threshold to an intensity at or above the press-input intensity threshold and, optionally, a subsequent decrease in intensity of the contact to an intensity at or below the hysteresis intensity, and the respective operation is performed in response to detecting the press input (e.g., the increase in intensity of the contact or the decrease in intensity of the contact, depending on the circumstances). 
     For ease of explanation, the description of operations performed in response to a press input associated with a press-input intensity threshold or in response to a gesture including the press input are, optionally, triggered in response to detecting either: an increase in intensity of a contact above the press-input intensity threshold, an increase in intensity of a contact from an intensity below the hysteresis intensity threshold to an intensity above the press-input intensity threshold, a decrease in intensity of the contact below the press-input intensity threshold, and/or a decrease in intensity of the contact below the hysteresis intensity threshold corresponding to the press-input intensity threshold. Additionally, in examples where an operation is described as being performed in response to detecting a decrease in intensity of a contact below the press-input intensity threshold, the operation is, optionally, performed in response to detecting a decrease in intensity of the contact below a hysteresis intensity threshold corresponding to, and lower than, the press-input intensity threshold. 
     Attention is now directed towards embodiments of devices, user interfaces, and associated processes that may be implemented on a multifunction device, such as devices  100 ,  300 ,  500 , and/or  550 , to improve a user&#39;s experience in manipulating user interface objects. 
       FIGS.  6 A- 6 F  illustrate exemplary user interfaces for manipulating user interface objects using an electronic device, in accordance with some embodiments. In some embodiments, the electronic device is device  500 . The electronic device has a display (e.g.,  112 ,  340 ,  504 ) and a rotatable input mechanism (e.g.,  506 ). 
       FIG.  6 A  illustrates a document  602 , which is an example of a user interface object. Document  602  includes a title  604 A, a paragraph of body text  606 A, and an image  608 A. The electronic device is configured to allow a user to scroll through document  602 , such that only a portion of the document  602  is visible on the display (e.g.,  504 ) at a particular time. The scroll position of the document is a characteristic of the document. The value of the scroll position of the document changes as the document is scrolled. 
     The user interface figures described optionally include a series (e.g.,  610 ) that shows the range of the characteristic of the object. These series are typically not part of the displayed user interface, but are provided to aid in the interpretation of the figures. In this example, the scroll position of the document can range from 0.0 to 1.0, as illustrated in the series  610  having a scroll position (e.g., the characteristic) ranging between 0.0 (e.g.,  610 A) to 1.0 (e.g.,  610 B). 
     In this example, the series  610  includes various subsets of the range of the series  610 , which modify how the object&#39;s characteristic is manipulated by a user. Subset  604 B, subset  606 B, and subset  608 B are illustrated in  FIG.  6 A . As with the series, subsets illustrated in the figures are typically not part of the displayed user interface, but are provided to aid in the interpretation of the figures. For example, the range of subset  606 B is from  606 C (e.g., scroll position value of 0.42) to  606 D (e.g., scroll position value of 0.56) on the series  610 . The scrolling behavior of the document  602  varies when the value of the scroll position of the document  602  is within the range of the subset  606 B, as compared to scrolling behavior just prior to entry into the range of subset  606 B. In some embodiments, scrolling behavior of the document varies between a first behavior when the scroll position is within the range of any of subsets  604 B,  606 B, and  608 B, as compared to a second behavior when the scroll position is not within any of the subsets. In some embodiments, scrolling behavior is different for each of the subsets  604 B,  606 B, and  608 B as compared to each other and as compared to scrolling behavior when outside any subset. 
       FIG.  6 B  illustrates a viewable display area  620 , a rotatable input mechanism (e.g.,  506 ), and a scroll value indicator  622  of an electronic device (e.g., device  500 ). The viewable display area  620  encompasses an exemplary area identifying the displayed user interface. For example, display area  620  illustrates the portion of the document  602  that is displayed on the display when the document  602  is scrolled using the rotatable input mechanism  506 . The scroll value indicator  622  helps in the interpretation of the figures by illustrating the value of the scroll position of the document  602 , as will be described in relation to  FIGS.  6 C- 6 E . The scroll value indicator  622  is typically not part of the displayed user interface. 
       FIG.  6 C  illustrates the viewable portion of document  602 , as illustrated by display area  620 . In  FIG.  6 C , the value of the scroll position of the document is illustrated by scroll value indicator  622  (e.g., scroll position value of 0.63). The device displays, on the display, the object (e.g., document  602 ) in accordance with a value (e.g., scroll position value of 0.63 in  FIG.  6 C ) of a characteristic (e.g., scroll position) of the object, the value being within a range of values of the characteristic (e.g., within the series  610  ranging from 0.0 to 1.0). In other examples, the characteristic of the object may be, for example, the zoom size (e.g., magnification) of the object or the degree of rotation of the object. 
     The device receives a user input request, the user input request representing rotation of the rotatable input mechanism (e.g.,  506 ). For example, the user rotates the rotatable input mechanism  506  in order to change the scroll position of the document  602 . 
     The device determines whether the value (e.g., the scroll position value) of the characteristic (e.g., scroll position) of the object (e.g.,  602 ) is within a predetermined subset (e.g., within the range of subset  606 B) of the range of values (e.g.,  610 ) of the characteristic. 
     In accordance with a determination that the value (e.g., scroll position value) of the characteristic (e.g., scroll position) of the object (e.g.,  602 ) is not within the predetermined subset of the range of values of the characteristic, the device updates the value (e.g., scroll position value) of the characteristic (e.g., scroll position) of the object within the range of values of the characteristic based on the user input request and in accordance with a second function, as illustrated in  FIGS.  6 C- 6 D . 
     In accordance with a determination that the value (e.g., scroll position value) of the characteristic (e.g., scroll position) of the object (e.g.,  602 ) is within the predetermined subset (e.g.,  606 B) of the range of values of the characteristic, the device updates the value (e.g., scroll position value) of the characteristic (e.g., scroll position) of the object within the range of values of the characteristic based on the user input request and in accordance with a first function, as illustrated in  FIG.  6 E . The first function and the second function are different functions. 
     Thus, as the user rotates the rotatable input mechanism, document  602  begins to scroll on the display. As illustrated in  FIGS.  6 C- 6 D , during certain portions of the scroll (e.g., while not within subsets  604 B,  606 B, and  606 C), the scrolling occurs based on the second function. As illustrated in  FIG.  6 E , during other portions of the scroll (e.g., while within subset  606 B), the scrolling occurs based on the first function. For example, a particular rotation of the rotatable input mechanism can be used to scroll through the entire range between subsets  608 B and  606 B (e.g., starting at scroll position value 0.70 and scrolling from 0.70 to 0.56 based on the second function). However, the same particular rotation of the rotatable input mechanism may only scroll through a portion of the subset  608 B (e.g., starting at scroll position value 0.56 and scrolling from 0.56 to 0.53 based on the first function). By reducing the amount that the document is scrolled while within a subset (e.g.,  606 B), the device provides higher resolution (and therefore more precision) for scrolling through those portions of the document; doing so may also encourage increased user dwell-time on certain portions of the document. In some embodiments, the subsets can be configured to align with particular aspects of the document, such as title  604 A, paragraph of body text  606 A, and image  608 A, in order to more allow for more precise scrolling through those aspects of the document. 
       FIG.  6 F  illustrates manipulating the zoom of an object (e.g., an image  612 ). The image (e.g.,  612 ) is displayed in accordance with a value (e.g., zoom size value) of a characteristic (e.g., zoom size) of the object, the value being within a range of values of the characteristic (e.g., along series  614 ). In this example, the subsets  612 A,  612 B,  612 C may be used to speed up the change in the characteristic. Thus, as the user rotates the rotatable input mechanism, the image zooms according to different zoom size values. While the zoom size values are within subsets  612 A,  612 B,  612 C, the progression along series  612  happens quickly (e.g., a slight turn of the rotatable input mechanism changes the zoom of the image significantly). While the zoom size values are not within subsets  612 A,  612 B,  612 C, the progression along series  612  happens slowly (e.g., even a significant turn of the rotatable input mechanism only slight changes the zoom of the image). As a result, the device provides higher resolution (and therefore more precision) for zooming through certain zoom size values. 
     When the image reaches the minimum (e.g., 0.0) zoom size, the image may shrink to less than the 0.0 level of zoom before returning to the 0.0 level of zoom. This rubberbanding effect provides an indication to the user that the minimum zoom limit has been reached. Similarly, when the image reaches the maximum (e.g., 1.0) zoom size, the image may enlarge beyond the 1.0 level of zoom before returning to the 1.0 level of zoom. This rubberbanding effect provides an indication to the user that the maximum zoom limit has been reached. 
     In accordance with some embodiments, updating display of the object (e.g.,  602 ,  612 ) in accordance with the updated value of the characteristic (e.g., scroll position, zoom size) of the object comprises animating the object to reflect the updated value of the characteristic of the object (e.g., animate the document scrolling or animate the object zooming). 
     In accordance with some embodiments, the predetermined subset of the range of values (e.g.,  606 B) of the characteristic includes an intermediate value (e.g.,  606 E), the intermediate value being inclusively within the predetermined subset of the range of values of the characteristic (e.g., a value between and inclusive of the start value and the end value). The first function is based on the intermediate value (e.g.,  606 E) of the subset of the range of values. Thus, for example, the behavior of the characteristic (e.g., the scroll behavior or zoom behavior), changes based on distance to the intermediate value. In accordance with some embodiments, the intermediate value of the predetermined subset (e.g.,  606 B) of the range of values of the characteristic is the mid-range value. 
     In accordance with some embodiments, the first function is based on a difference between the value of the characteristic of the object and the intermediate value. Thus, as an example, the precision with which the document can be scrolled increases as the document is scrolled closer to the center of the predetermined subset and the precision with which the document can be scrolled decreases again as the document is scrolled away from the center of the predetermined subset. For example, while the document scroll position is further from the intermediate value, an incremental rotation of the rotatable input mechanism causes more scrolling than the same incremental rotation of the rotatable input mechanism, while the document scroll position is closer to the intermediate value. 
     In accordance with some embodiments, the updated value is based on an attribute of the user input request. In accordance with some embodiments, the attribute of the user input request is one or more of angular velocity of the rotatable input mechanism and angular acceleration of the rotatable input mechanism. 
     In accordance with some embodiments, updating the value (e.g., scroll position value or zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object (e.g.,  602 ,  612 ) within the range of values of the characteristic based on the user input request and in accordance with the second function comprises: determining whether the value (e.g., scroll position value, zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object is within a second predetermined subset (e.g.,  608 B) of the range of values of the characteristic, wherein the predetermined subset (e.g.,  606 B) and the second predetermined subset (e.g.,  608 B) are different. In accordance with a determination that the value (e.g., scroll position value or zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object is within the second predetermined subset of the range of values of the characteristic, further updating the value of the characteristic of the object within the range of values of the characteristic based on the user input request and in accordance with a third function. The first function, the second function, and the third function are different functions. Thus, in one example, different predetermined subsets can cause varying behaviors. In another example, two or more predetermined subsets may overlap, and their effects combine for the overlapped range. 
     In accordance with some embodiments, the range of values of the characteristic is along a single dimension (e.g., the range is not a multi-dimension X-Y range). In accordance with some embodiments, the range of values of the characteristic is a linear series. 
     In accordance with some embodiments, in accordance with a determination that the value (e.g., scroll position value, zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object (e.g.,  602 ,  612 ) is within the predetermined subset (e.g.,  606 B,  612 B) of the range of values of the characteristic, the device performs a haptic alert at the electronic device, such as a mechanical (e.g., tactile feedback) or audible (e.g., audio file playback) haptic alert. 
     In accordance with some embodiments, the object is selected from the group consisting of a document and an image. Examples of a document include, but are not limited to: a message, a text message, a text message conversation, an email, a presentation, a spreadsheet, a user editable file (e.g., a word processing file), a user ineditable file (e.g., a PDF file), a webpage, a list of items (e.g., list of contacts, list of music, list of calendar events, list of messages, list of files, list of folders). In accordance with some embodiments, the characteristic of the object is selected from the group consisting of scroll position (e.g., how far up/down or left/right is the object scrolled), zoom size (e.g., how large/small is magnification of the document), and degree of rotation (e.g., how many radians is the object rotated). In accordance with some embodiments, the characteristic of the object is scroll position and the predetermined subset of the range of values of the characteristic is a range of scroll positions. In accordance with some embodiments, the characteristic of the object is zoom size and the predetermined subset of the range of values of the characteristic is a range of zoom sizes. 
       FIG.  7    is a flow diagram illustrating an exemplary process for manipulating user interface objects in accordance with some embodiments. In some embodiments, method  700  may be performed at an electronic device with a display (e.g.,  112 ,  340 ,  504 ) and a rotatable input mechanism (e.g.,  506 ). Some operations in method  700  may be combined, the order of some operations may be changed, and some operations may be omitted. Exemplary devices that may perform method  700  include devices  100 ,  300 ,  500 , and/or  550  ( FIGS.  1 A,  3 ,  5 A, and  5 C ). 
     Method  700  provides an intuitive way to manipulate user interface objects. The method reduces the cognitive burden on a user when using a device to manipulate a user interface object, such as scrolling, zooming, or rotating an object, thereby creating a more efficient human-machine interface. For battery-operated computing devices, enabling a user to manipulate user interface objects more efficiently conserves power and increases the time between battery charges. 
     At block  702 , an object (e.g., document  602 ) is displayed in accordance with a value (e.g., scroll position value of 0.63 in  FIG.  6 C ) of a characteristic (e.g., scroll position) of the object (e.g., document  602 ), the value being within a range of values (e.g., range 0.0 to 1.0 of series  610 ) of the characteristic (e.g., scroll position). 
     At block  704 , a user input request is received. The user input request represents rotation of the rotatable input mechanism (e.g.,  506 ). 
     At block  706 , it is determined whether the value (e.g., scroll position value or zoom size value) of the characteristic (e.g., scroll position or zoom size) of the object is within a predetermined subset of the range of values of the characteristic (e.g., within  604 B,  606 B, or  608 B). 
     At block  708 , in accordance with a determination that the value (e.g., scroll position value or zoom size value) of the characteristic (e.g., scroll position or zoom size) of the object is within the predetermined subset of the range of values of the characteristic (e.g., indicator  622  is within subset  608 D in  FIGS.  6 D- 6 E ), the value (e.g., scroll position value or zoom size value) of the characteristic (e.g., scroll position or zoom size) of the object is updated within the range of values of the characteristic based on the user input request and in accordance with a first function. 
     At block  710 , in accordance with a determination that the value (e.g., scroll position value or zoom size value) of the characteristic (e.g., scroll position or zoom size) of the object (e.g., document  602 ) is not within the predetermined subset of the range of values of the characteristic (e.g., indicator  622  is not within any subsets, as in  FIG.  6 C ), updating the value (e.g., scroll position value or zoom size value) of the characteristic of the object within the range of values of the characteristic based on the user input request and in accordance with a second function, wherein the first function and the second function are different functions. 
     At block  712 , display of the object (e.g., document  602 ) is updated in accordance with the updated value of the characteristic of the object (e.g., to reflect the scroll on the display). 
     In accordance with some embodiments, updating display of the object (e.g.,  602 ,  612 ) in accordance with the updated value of the characteristic (e.g., scroll position, zoom size) of the object comprises animating the object to reflect the updated value of the characteristic of the object (e.g., animate the document scrolling or animate the object zooming). 
     In accordance with some embodiments, the predetermined subset of the range of values (e.g.,  606 B) of the characteristic includes an intermediate value (e.g.,  606 E), the intermediate value being inclusively within the predetermined subset of the range of values of the characteristic (e.g., a value between and inclusive of the start value and the end value). The first function is based on the intermediate value (e.g.,  606 E) of the subset of the range of values. In accordance with some embodiments, the intermediate value of the predetermined subset (e.g.,  606 B) of the range of values of the characteristic is the mid-range value. 
     In accordance with some embodiments, the first function is based on a difference between the value of the characteristic of the object and the intermediate value. In accordance with some embodiments, the updated value is based on an attribute of the user input request. In accordance with some embodiments, the attribute of the user input request is one or more of angular velocity of the rotatable input mechanism and angular acceleration of the rotatable input mechanism. 
     In accordance with some embodiments, updating the value (e.g., scroll position value or zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object (e.g.,  602 ,  612 ) within the range of values of the characteristic based on the user input request and in accordance with the second function comprises: determining whether the value (e.g., scroll position value, zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object is within a second predetermined subset (e.g.,  608 B) of the range of values of the characteristic, wherein the predetermined subset (e.g.,  606 B) and the second predetermined subset (e.g.,  608 B) are different. In accordance with a determination that the value (e.g., scroll position value or zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object is within the second predetermined subset of the range of values of the characteristic, further updating the value of the characteristic of the object within the range of values of the characteristic based on the user input request and in accordance with a third function. The first function, the second function, and the third function are different functions. 
     In accordance with some embodiments, the range of values of the characteristic is along a single dimension (e.g., the range is not a multi-dimension X-Y range). In accordance with some embodiments, the range of values of the characteristic is a linear series. 
     In accordance with some embodiments, in accordance with a determination that the value (e.g., scroll position value, zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object (e.g.,  602 ,  612 ) is within the predetermined subset (e.g.,  606 B,  612 B) of the range of values of the characteristic, the device performs a haptic alert at the electronic device, such as a mechanical (e.g., tactile feedback) or audible (e.g., audio file playback) haptic alert. 
     In accordance with some embodiments, the object is selected from the group consisting of a document and an image. Examples of a document include, but are not limited to: a message, a text message, a text message conversation, an email, a presentation, a spreadsheet, a user editable file (e.g., a word processing file), a user ineditable file (e.g., a PDF file), a webpage, a list of items (e.g., list of contacts, list of music, list of calendar events, list of messages, list of files, list of folders). In accordance with some embodiments, the characteristic of the object is selected from the group consisting of scroll position (e.g., how far up/down or left/right is the object scrolled), zoom size (e.g., how large/small is magnification of the document), and degree of rotation (e.g., how many radians is the object rotated). In accordance with some embodiments, the characteristic of the object is scroll position and the predetermined subset of the range of values of the characteristic is a range of scroll positions. In accordance with some embodiments, the characteristic of the object is zoom size and the predetermined subset of the range of values of the characteristic is a range of zoom sizes. 
     In accordance with some embodiments, analysis of the object is not required to specify the subsets. For example, the subsets may be associated with the object (e.g., embedded in the document) prior to the object being accessed at the device. Such predefined subsets may be manually specified by the author of the object. 
     The subsets described in relation to  FIGS.  6 - 7    (e.g.,  604 B,  606 B,  608 B,  612 A,  612 B,  612 C) have the technical advantage of allowing coarse input to be translated to precise control. Certain portions of documents (or certain zoom sizes, certain degrees of rotation) can be made easier or more difficult to move through or move away from, facilitating the process of directing the user&#39;s focus. Further, the subsets of a particular object may have different properties, such as different size of ranges. The subsets can be used to direct the “flow” through a document to allow for curation. 
     Note that details of the processes described above with respect to method  700  ( FIG.  7   ) are also applicable in an analogous manner to the methods described above and below. For example, method  700  may include one or more of the characteristics of the various methods described above with reference to the processes in  FIGS.  9 A,  9 B,  11 ,  13 K,  22 ,  31 ,  39 , and  46   . For brevity, these details are not repeated below. 
     It should be understood that the particular order in which the operations in  FIG.  11    have been described is exemplary and not intended to indicate that the described order is the only order in which the operations could be performed. One of ordinary skill in the art would recognize various ways to reorder the operations described herein, as well as excluding certain operations. For brevity, these details are not repeated here. Additionally, it should be noted that aspects of the methods and processes described throughout this description may be incorporated with one another. 
       FIGS.  8 A- 8 F  illustrate exemplary user interfaces for manipulating user interface objects using an electronic device, in accordance with some embodiments. In some embodiments, the electronic device is device  500 . The electronic device has a display (e.g.,  112 ,  340 ,  504 ) and a rotatable input mechanism (e.g.,  506 ). 
       FIG.  8 A  illustrates a document  802 , which is an example of a user interface object. Document  802  includes a title  804 A, a paragraph of body text  806 A, and an image  808 A. In some embodiments, the electronic device is configured to allow a user to scroll through document  802 , such that only a portion of the document  802  is visible on the display (e.g.,  504 ) at a particular time. The scroll position of the document  802  is a characteristic of the document. The value of the scroll position of the document changes as the document is scrolled. 
     The user interface figures described optionally include a series (e.g.,  810 ) that shows the range of the characteristic of the object. These series are typically not part of the displayed user interface, but are provided to aid in the interpretation of the figures. In this example, the scroll position of the document can range from 0.0 to 1.0, as illustrated in the series  810  having a scroll position (e.g., the characteristic) ranging between 0.0 (e.g.,  810 A) to 1.0 (e.g.,  810 B). 
     In this example, the series  810  includes various anchors within the range of the series  810 , which modify how the object&#39;s characteristic is manipulated by a user. Anchor  804 B, anchor  806 B, and anchor  808 B are illustrated in  FIG.  8 A . As with the series, anchors illustrated in the figures are typically not part of the displayed user interface, but are provided to aid in the interpretation of the figures. For example, the zone of anchor  806 B is from  806 E (e.g., scroll position value of 0.25) to  806 D (e.g., scroll position value of 0.45) on the series  810 . When the value of the scroll position of the document  802  transitions into the range of the anchor  806 B, the document  802  is scrolled to the intermediate value  806 C of the anchor  806 D, as described in detail below. 
       FIG.  8 B  illustrates a viewable display area  820 , a rotatable input mechanism (e.g.,  506 ), and a scroll value indicator  822 . The viewable display area  820  encompasses an exemplary area identifying the displayed user interface. For example, display area  820  illustrates the portion of the document  802  that is displayed on the display when the document  802  is scrolled using the rotatable input mechanism  506 . The scroll value indicator  822  helps in the interpretation of the figures by illustrating the value of the scroll position of the document  802 , as will be described in relation to  FIGS.  8 C- 8 E . The scroll value indicator  822  is typically not part of the displayed user interface. 
       FIG.  8 C  illustrates the viewable portion of document  802 , as illustrated by display area  820 . In  FIG.  8 C , the value of the scroll position of the document is indicated by scroll value indicator  822  (e.g., 0.50). The device displays, on the display, the object (e.g., document  802 ) in accordance with a value (e.g., 0.50 in  FIG.  8 C ) of a characteristic (e.g., scroll position) of the object, the value being within a range of values of the characteristic (e.g., within the series  810  ranging from 0.0 to 1.0). In other examples, the characteristic of the object may be, for example, the zoom size (e.g., magnification) of the object or the degree of rotation of the object. 
     The device receives a user input request, the user input request representing rotation of the rotatable input mechanism (e.g.,  506 ). For example, the user rotates the rotatable input mechanism  506  in order to change the scroll position of the document  802 . 
     In response to receiving the user input request, the device determines whether the user input request causes the value (e.g., scroll position value or zoom size value) of the characteristic (e.g., scroll level or zoom size) of the object to transition into range of a zone of an anchor (e.g.,  806 B). The anchor (e.g.,  806 B) has a start value (e.g.,  806 E), an intermediate value (e.g.,  806 C), and an end value (e.g.,  806 D) within the range of values of the characteristic. The zone of the anchor is between the start value (e.g.,  806 E) and the end value (e.g.,  806 D) of the anchor  806 B. The zone of the anchor is the range over which the anchor influences the object, such as by causing it to scroll to the intermediate value (e.g.,  806 C), as is detailed below. 
     In accordance with a determination that the user input request causes the value (e.g., scroll position value or zoom size value) of the characteristic (e.g., scroll position or zoom size) of the object (e.g.,  802 ) to transition into range of the zone of the anchor, the device updates the value of the characteristic of the object based on the intermediate value (e.g.,  808 C) of the anchor. Thus, when the document is being scrolled and the scroll position value of the document enters into range of a particular anchor, the device sets the scroll position value of the document to the intermediate value of that particular anchor. The device also updates display of the object (e.g.,  802 ) in accordance with the updated value of the characteristic of the object. Thus, the device displays the document scrolled to the intermediate value of that anchor. 
     This concept is illustrated in  FIGS.  8 C- 8 E . In  FIG.  8 C , the document  802  is not being scrolled. Once the device receives input at the rotatable input mechanism, the device begins scrolling the document in accordance with the input. In this example, the input indicates to scroll toward the top of the document  802 . When the value of the characteristic transitions into range of anchor  806 B, as illustrated in  FIG.  8 D , the device scrolls the document to the intermediate point  806 C of the anchor  806 D as illustrated in  FIG.  8 E . 
     As a result of the anchors, the device simplifies the alignment of contents of the document for the user. When a particular content reaches an anchor, the document automatically scrolls (sometimes referred to as “snapping”) to the intermediate point of that anchor. For example, this allows various content in a document to be efficiently aligned with a particular location on the display, facilitate the user&#39;s ability to scroll to those particular portions of the content. 
       FIG.  8 F  illustrates manipulating the zoom of an object (e.g., an image  812 ). The image (e.g.,  812 ) is displayed in accordance with a value (e.g., zoom size value) of a characteristic (e.g., zoom size) of the object, the value being within a range of values of the characteristic (e.g., along series  814 ). In this example, the anchors  812 A,  812 B, and  812 C may be used to guide the change in the zoom characteristic. Thus, as the user rotates the rotatable input mechanism, the image zooms according to different zoom size values. When the zoom size value transitions into one of anchors  812 A,  812 B, and  812 C, the device automatically changes the zoom of the image to the corresponding intermediate value of the anchor. As a result, the device facilitates access manipulating an object to particular zoom size values. When the image reaches the minimum (e.g., 0.0) zoom size, the image may shrink to less than the 0.0 level of zoom before returning to the 0.0 level of zoom. This rubberbanding effect provides an indication to the user that the minimum zoom limit has been reached. Similarly, when the image reaches the maximum (e.g., 1.0) zoom size, the image may enlarge beyond the 1.0 level of zoom before returning to the 1.0 level of zoom. This rubberbanding effect provides an indication to the user that the maximum zoom limit has been reached. 
     In accordance with some embodiments, updating display of the object (e.g.,  802 ,  812 ) in accordance with the updated value of the characteristic (e.g., scroll position, zoom size) of the object comprises animating the object to reflect the updated value of the characteristic of the object (e.g., animate the document scrolling or animate the object zooming). That is, while the value of the characteristic is updated to the value of the intermediate value upon transitioning into the range of the anchor, the user interface may display the updating of scroll (or zoom) position graphically over a period of time via an animation of updating to the scroll (or zoom) position corresponding to the intermediate value. Doing so may reduce the abruptness of the updating. 
     In accordance with some embodiments (e.g., anchor  806 ), the intermediate value (e.g.,  806 C) is not equal to the start value (e.g.  806 E) or the end value (e.g.,  806 D). In accordance with some embodiments (e.g., anchor  804 ), the intermediate value (e.g.,  804 C) is equal to the start value (e.g.,  804 C) or the end value. 
     In accordance with some embodiments, updating the value of the characteristic of the object based on the intermediate value of the anchor comprises updating the value of the characteristic of the object to be equal to the intermediate value of the anchor (e.g., the device sets the scroll or zoom value to the intermediate point). 
     In accordance with some embodiments, the start value and the end value are different. In accordance with some embodiments, the intermediate value is not the average of the start value and the end value. 
     In some embodiments, in accordance with a determination that the user input request causes the value (e.g., scroll position value, zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object to transition into range of the zone of the anchor, the device initiates a duration (e.g., a time period) during which received user input requests to manipulate the characteristic of the object do not affect the displayed characteristic of the object. Thus, once the value of the characteristic of the object falls within the start value and the end value, further user input during a particular time period does not affect the visual display of the object. This is helpful, for example, to give the user time to visually recognize that the object has moved or is moving to an intermediate value of an anchor. 
     In accordance with some embodiments, the duration is based on the rate of change of the value of the characteristic of the object when the value of the characteristic of the object transitions into range of the zone of the anchor. For example, if a document is being scrolled at a high scroll rate when it transitions into range of an anchor, the duration may be shorter than if the document was scrolled at a low scroll rate. 
     In some embodiments, in accordance with a determination that the user input request does not cause the value (e.g., scroll position value, zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object to transition into range of the zone of the anchor (e.g., the scroll position/zoom size of the object is between two anchor zones) or into range of a zone of a second anchor (e.g., anchor  808 B), the second anchor having a second start value, a second intermediate value, and a second end value, and the second anchor having a zone between the second start value and the second end value, the device updates the value of the characteristic of the object in accordance with the user input (e.g., the device scrolls the document to a stopping point not within the zone of any anchor). The device also updates display of the object in accordance with the updated value of the characteristic of the object (e.g., the device displays the document scrolled according to the stopping point). The device identifies a closest anchor, from among at least the anchor and the second anchor, based on the updated value of the characteristic of the object in accordance with the user input. Subsequently the device updates the value of the characteristic of the object based on the corresponding intermediate value of the identified closest anchor (e.g., set the scroll position value to the intermediate value of the closest anchor, or set the zoom size value to the intermediate value of the closest anchor). The device also updates display of the object in accordance with the subsequently updated value of the characteristic of the object (e.g., display the document scrolled according to the intermediate value of the closest anchor or display the object zoomed according to the intermediate value of the closest anchor). 
     In accordance with some embodiments, identifying the closest anchor comprises: calculating a difference between the updated value of the characteristic of the object in accordance with the user input request and the intermediate value of the anchor, and calculating a difference between the updated value of the characteristic of the object in accordance with the user input request and the intermediate value of the second anchor. 
     In accordance with some embodiments, identifying the closest anchor comprises identifying the nearest of the start value and end value of the anchor and the second anchor. 
     In some embodiments, in accordance with a determination that the user input request causes the value (e.g., scroll position value, zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object to transition into range of the zone of the anchor, the device performs a haptic alert at the electronic device, such as a mechanical or audible (e.g., audio playback) haptic alert. 
     In accordance with some embodiments, the object is a document and the characteristic of the object is scroll position. Examples of a document include, but are not limited to: a message, a text message, a text message conversation, an email, a presentation, a spreadsheet, a user editable file (e.g., a word processing file), a user ineditable file (e.g., a PDF file), a webpage, a list of items (e.g., list of contacts, list of music, list of calendar events, list of messages, list of files, list of folders). The device analyzes at least a portion of the document, wherein analyzing at least the portion of the document comprises identifying locations within the document. 
     In accordance with some embodiments, the locations within the document include one or more of: one or more page boundaries of at least the portion of the document, one or more paragraph boundaries of at least the portion of the document, and one or more keyword locations of at least the portion of the document. The device assigns anchors to some or all of the identified page boundaries, paragraph boundaries, and keyword locations of the document. 
     In accordance with some embodiments, the device accesses a first set of anchor points (e.g., anchor points indicate where anchors should go, such as at paragraphs and images), assigns respective anchors to the first set of anchor points, detects a change in value of the characteristic of the object (e.g., the document has been scrolled). In response to detecting the change in the value of the characteristic of the object, the device accesses a second set of anchor points (e.g., the document has scrolled and more anchors are required) and assigns respective anchors to the second set of anchor points, wherein the first set of anchor points and the second set of anchor points are different. 
     In accordance with some embodiments, the manipulation of the object is affected by both anchors and by subsets, as described above. The device determines whether the user input causes the value (e.g., scroll position value, zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object to transition into range of the zone of the anchor, the device determines whether the value of the characteristic of the object is also within a predetermined subset of the range of values of the characteristic. In accordance with a determination that the value of the characteristic of the object is within the predetermined subset of the range of values of the characteristic, calculating the value of the characteristic of the object within the range of values of the characteristic based on the user input request and in accordance with a first function. In accordance with a determination that the value of the characteristic of the object is not within the predetermined subset of the range of values of the characteristic, calculating the value of the characteristic of the object within the range of values of the characteristic based on the user input request and in accordance with a second function, wherein the first function and the second function are different functions. 
     In accordance with some embodiments, the object is a document or an image. Examples of a document include, but are not limited to: a message, a text message, a text message conversation, an email, a presentation, a spreadsheet, a user editable file (e.g., a word processing file), a user ineditable file (e.g., a PDF file), a webpage, a list of items (e.g., list of contacts, list of music, list of calendar events, list of messages, list of files, list of folders). In accordance with some embodiments, the characteristic of the object is scroll position (e.g., how far up/down is the object scrolled), zoom size (e.g., how large/small is the document zoomed), and degree of rotation (e.g., how many radians is the object rotated). 
       FIG.  9 A  is a flow diagram illustrating an exemplary process for manipulating user interface objects in accordance with some embodiments. In some embodiments, method  900  may be performed at an electronic device with a display (e.g.,  112 ,  340 ,  504 ) and a rotatable input mechanism (e.g.,  506 ). Some operations in method  900  may be combined, the order of some operations may be changed, and some operations may be omitted. Exemplary devices that may perform method  900  include devices  100 ,  300 ,  500 , and/or  550  ( FIGS.  1 A,  3 ,  5 A, and  5 C ). 
     Method  900  provides an intuitive way to manipulate user interface objects. The method reduces the cognitive burden on a user when using a device to manipulate a user interface object, such as scrolling, zooming, or rotating an object, thereby creating a more efficient human-machine interface. For battery-operated computing devices, enabling a user to manipulate user interface objects more efficiently conserves power and increases the time between battery charges. 
     At block  902 , an object (e.g., document  802 , image  812 ) is displayed in accordance with a value of a characteristic (e.g., scroll position in  FIGS.  8 C- 8 E , zoom size in  FIG.  8 F ) of the object, the value being within a range of values (e.g., 0.0 to 1.0) of the characteristic. 
     At block  904 , a user input request is received, the user input request representing rotation of the rotatable input mechanism (e.g.,  506 ). 
     At block  906 , in response to receiving the user input request, it is determined whether the user input request causes the value (e.g., scroll position value or zoom size value) of the characteristic (e.g., scroll position or zoom size) of the object to transition into range of a zone of an anchor (e.g., anchor  806 B, anchor  812 B), the anchor having a start value (e.g., at  806 E), an intermediate value (e.g., at  806 C), and an end value (e.g., at  806 D) within the range of values of the characteristic, and the zone of the anchor being between the start value and the end value. 
     At block  908 , in accordance with a determination that the user input request causes the value of the characteristic of the object to transition into range of the zone of the anchor (e.g.,  822  enters the zone of anchor  806 B, as illustrated in  FIG.  8 D ), blocks  910  and  912  are performed. 
     At block  910 , the value of the characteristic of the object is updated based on the intermediate value of the anchor (e.g., the scroll position value is set equal to the intermediate value  806 C). 
     At block  912 , display of the object is updated in accordance with the updated value of the characteristic of the object (e.g., the display of document  802  is updated to reflect the updated scroll position value, as illustrated in  FIG.  8 E ) 
     In accordance with some embodiments, updating display of the object (e.g.,  802 ,  812 ) in accordance with the updated value of the characteristic (e.g., scroll position, zoom size) of the object comprises animating the object to reflect the updated value of the characteristic of the object (e.g., animate the document scrolling or animate the object zooming). 
     In accordance with some embodiments (e.g., anchor  806 ), the intermediate value (e.g.,  806 C) is not equal to the start value (e.g.  806 E) or the end value (e.g.,  806 D). In accordance with some embodiments (e.g., anchor  804 ), the intermediate value (e.g.,  804 C) is equal to the start value (e.g.,  804 C) or the end value. 
     In accordance with some embodiments, updating the value of the characteristic of the object based on the intermediate value of the anchor comprises updating the value of the characteristic of the object to be equal to the intermediate value of the anchor (e.g., the device sets the scroll or zoom value to the intermediate point). 
     In accordance with some embodiments, the start value and the end value are different. In accordance with some embodiments, the intermediate value is not the average of the start value and the end value. 
     In some embodiments, in accordance with a determination that the user input request causes the value (e.g., scroll position value, zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object to transition into range of the zone of the anchor, the device initiates a duration (e.g., a time period) during which received user input requests to manipulate the characteristic of the object do not affect the displayed characteristic of the object. 
     In accordance with some embodiments, the duration is based on the rate of change of the value of the characteristic of the object when the value of the characteristic of the object transitions into range of the zone of the anchor. 
     In some embodiments, in accordance with a determination that the user input request does not cause the value (e.g., scroll position value, zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object to transition into range of the zone of the anchor (e.g., the scroll position/zoom size of the object is between two anchor zones) or into range of a zone of a second anchor (e.g., anchor  808 B), the second anchor having a second start value, a second intermediate value, and a second end value, and the second anchor having a zone between the second start value and the second end value, the device updates the value of the characteristic of the object in accordance with the user input (e.g., the device scrolls the document to a stopping point not within the zone of any anchor). The device also updates display of the object in accordance with the updated value of the characteristic of the object (e.g., the device displays the document scrolled according to the stopping point). The device identifies a closest anchor, from among at least the anchor and the second anchor, based on the updated value of the characteristic of the object in accordance with the user input. Subsequently the device updates the value of the characteristic of the object based on the corresponding intermediate value of the identified closest anchor (e.g., set the scroll position value to the intermediate value of the closest anchor, or set the zoom size value to the intermediate value of the closest anchor). The device also updates display of the object in accordance with the subsequently updated value of the characteristic of the object (e.g., display the document scrolled according to the intermediate value of the closest anchor or display the object zoomed according to the intermediate value of the closest anchor). 
     In accordance with some embodiments, identifying the closest anchor comprises: calculating a difference between the updated value of the characteristic of the object in accordance with the user input request and the intermediate value of the anchor, and calculating a difference between the updated value of the characteristic of the object in accordance with the user input request and the intermediate value of the second anchor. 
     In accordance with some embodiments, identifying the closest anchor comprises identifying the nearest of the start value and end value of the anchor and the second anchor. 
     In some embodiments, in accordance with a determination that the user input request causes the value (e.g., scroll position value, zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object to transition into range of the zone of the anchor, the device performs a haptic alert at the electronic device, such as a mechanical or audible (e.g., audio playback) haptic alert. 
     In accordance with some embodiments, the object (e.g.,  802 ) is a document and the characteristic of the object is scroll position. Examples of a document include, but are not limited to: a message, a text message, a text message conversation, an email, a presentation, a spreadsheet, a user editable file (e.g., a word processing file), a user ineditable file (e.g., a PDF file), a webpage, a list of items (e.g., list of contacts, list of music, list of calendar events, list of messages, list of files, list of folders). The device analyzes at least a portion of the document, wherein analyzing at least the portion of the document comprises identifying locations within the document. 
     In accordance with some embodiments, the locations within the document include one or more of: one or more page boundaries of at least the portion of the document, one or more paragraph boundaries of at least the portion of the document, and one or more keyword locations of at least the portion of the document. The device assigns anchors to some or all of the identified page boundaries, paragraph boundaries, and keyword locations of the document. 
     In accordance with some embodiments, the device accesses a first set of anchor points (e.g., anchor points indicate where anchors should go, such as at paragraphs and images), assigns respective anchors to the first set of anchor points, detects a change in value of the characteristic of the object (e.g., the document has been scrolled). In response to detecting the change in the value of the characteristic of the object, the device accesses a second set of anchor points (e.g., the document has scrolled and more anchors are required) and assigns respective anchors to the second set of anchor points, wherein the first set of anchor points and the second set of anchor points are different. 
     In accordance with some embodiments, the manipulation of the object is affected by both anchors and by subsets, as described above. The device determines whether the user input causes the value (e.g., scroll position value, zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object to transition into range of the zone of the anchor, the device determines whether the value of the characteristic of the object is also within a predetermined subset of the range of values of the characteristic. In accordance with a determination that the value of the characteristic of the object is within the predetermined subset of the range of values of the characteristic, calculating the value of the characteristic of the object within the range of values of the characteristic based on the user input request and in accordance with a first function. In accordance with a determination that the value of the characteristic of the object is not within the predetermined subset of the range of values of the characteristic, calculating the value of the characteristic of the object within the range of values of the characteristic based on the user input request and in accordance with a second function, wherein the first function and the second function are different functions. 
     In accordance with some embodiments, the object is a document or an image. Examples of a document include, but are not limited to: a message, a text message, a text message conversation, an email, a presentation, a spreadsheet, a user editable file (e.g., a word processing file), a user ineditable file (e.g., a PDF file), a webpage, a list of items (e.g., list of contacts, list of music, list of calendar events, list of messages, list of files, list of folders). In accordance with some embodiments, the characteristic of the object is scroll position (e.g., how far up/down is the object scrolled), zoom size (e.g., how large/small is the document zoomed), and degree of rotation (e.g., how many radians is the object rotated). 
     In accordance with some embodiments, analysis of the object is not required to specify the anchors. For example, the anchors may be associated with the object (e.g., embedded in the document) prior to the object being accessed at the device. Such predefined anchors may be manually specified by the author of the object. 
     The anchors described in relation to  FIGS.  8  and  9 A  (e.g.,  804 B,  806 B,  808 B,  812 A,  812 B,  814 C) have the technical advantage of allowing coarse input to be translated to precise control. Certain portions of documents (or certain zoom sizes, certain degrees of rotation) can be made easier or more difficult to move to, facilitating the process of directing the user&#39;s focus. Further, the anchors of a particular object may have different properties, such as different size of ranges. The anchors can be used to direct the “flow” through a document to allow for curation. 
     Note that details of the processes described above with respect to method  900  ( FIG.  9 A ) are also applicable in an analogous manner to the methods described above and below. For example, method  900  may include one or more of the characteristics of the various methods described above with reference to the processes in  FIGS.  7 ,  9 B,  11 ,  13 K,  22 ,  31 ,  39 , and  46   . For brevity, these details are not repeated below. 
     It should be understood that the particular order in which the operations in  FIG.  11    have been described is exemplary and not intended to indicate that the described order is the only order in which the operations could be performed. One of ordinary skill in the art would recognize various ways to reorder the operations described herein, as well as excluding certain operations. For brevity, these details are not repeated here. Additionally, it should be noted that aspects of the methods and processes described throughout this description may be incorporated with one another. 
     In a separate embodiment,  FIGS.  8 G- 8 H  illustrate exemplary user interfaces for manipulating user interface objects using an electronic device. In some embodiments, the electronic device is device  500 . The electronic device has a display (e.g.,  112 ,  340 ,  504 ) and a rotatable input mechanism (e.g.,  506 ). 
       FIGS.  8 G- 8 H  illustrate a document  842 , which is an example of a user interface object. In some embodiments, the electronic device is configured to allow a user to scroll through document  842 , such that only a portion of the document  842  is visible on the display (e.g.,  504 ) at a particular time. The scroll position of the document  842  is a characteristic of the document. The value of the scroll position of the document changes as the document is scrolled. 
     The user interface figures described optionally include a series (e.g.,  850 ) that shows the range of the characteristic of the object. These series are typically not part of the displayed user interface, but are provided to aid in the interpretation of the figures. In this example, the scroll position of the document can range from 0.0 to 1.0. 
     In this example, the series  850  includes various anchors within the range of the series  850 , which modify how the object&#39;s characteristic is manipulated by a user. Anchor  844 B, anchor  846 B are illustrated in  FIG.  8 G . As with the series, anchors illustrated in the figures are typically not part of the displayed user interface, but are provided to aid in the interpretation of the figures. The zone of anchor  844 B is from  844 E (e.g., scroll position value of 0.30) to  844 D (e.g. 0.50) on the series  850 . The zone of anchor  846 B is from  846 E (e.g., value of 0.60) to  846 D (e.g., value of 0.95) on the series  850 . When the value of the scroll position of the document  842  reaches a steady state (i.e., the document stops scrolling), the device scrolls the document  842  to the intermediate value of the nearest anchor, as described in detail below. This aligns the document  842  on the display (e.g.,  504 ) for the user&#39;s ease of viewing. 
       FIGS.  8 G- 8 H  also illustrate a viewable display area  860  and a scroll value indicator  862 . The viewable display area  860  encompasses an exemplary area identifying the displayed user interface. For example, display area  860  illustrates the portion of the document  842  that is displayed on the display when the document  842  is scrolled using a rotatable input mechanism (e.g.,  506 ). The scroll value indicator  862  helps in the interpretation of the figures by illustrating the value of the scroll position of the document  842 . The scroll value indicator  862  is typically not part of the displayed user interface. 
       FIG.  8 G  illustrates a viewable portion of document  842 , as illustrated by display area  860 . The device displays, on the display, the object (e.g., document  802 ) in accordance with a value of a characteristic (e.g., scroll position) of the object, the value being within a range of values of the characteristic (e.g., within the series  850  ranging from 0.0 to 1.0). In other examples, the characteristic of the object may be, for example, the zoom size (e.g., magnification) of the object or the degree of rotation of the object. 
     The device receives a user input request, the user input request representing rotation of the rotatable input mechanism (e.g.,  506 ). For example, the user rotates the rotatable input mechanism  506  in order to change the scroll position of the document  842 . 
     In response to receiving the user input request, the device updates the value (e.g., scroll position value, zoom size value) of the characteristic (e.g., scroll position, zoom size) of the object within the range of values of the characteristic based on the user input request, and the device updates the display of the object in accordance with the updated value of the characteristic of the object. In the example of  FIGS.  8 G- 8 H , the device has scrolled the document and the document has stopped scrolling. The value of the scroll position of the document is illustrated by scroll value indicator  862  (e.g., scroll position value of 0.53). Thus, when the device receives the user input, the device scrolls the document  842  to the updated scroll position value (e.g., 0.53). In some examples, the document  842  reaches a steady state and stops scrolling once it reaches the updated scroll position value. 
     The device identifies a closest anchor to the updated value (e.g., 0.53) of the characteristic of the object (e.g., once the document stops scrolling), the closest anchor identified from among at least a first anchor (e.g., anchor  844 B) having a corresponding intermediate value (e.g.,  844 C) and a second anchor (e.g., anchor  846 B) having a corresponding intermediate value (e.g.,  846 C). 
     Subsequently the device updates the value of the characteristic of the object based on the corresponding intermediate value of the identified closest anchor. The device also updates display of the object in accordance with the subsequently updated value of the characteristic of the object. Thus, the device sets the value of the characteristic of the object equal to the intermediate value of the closest anchor and scrolls the document to the intermediate value of the closest anchor. In an example where the characteristic is zoom size, the magnification of the object is change to the intermediate value of the closest anchor. 
     In accordance with some embodiments, updating display of the object in accordance with the subsequently updated value of the characteristic of the object comprises animating the object to reflect the subsequently updated value of the characteristic of the object. Thus, for example, the scroll of the document  842  from the stopped (steady state) scroll position to the subsequently updated value is animated. 
     In accordance with some embodiments, the corresponding intermediate value of the identified closest anchor is between the respective start value (e.g.,  846 E) and the respective end value (e.g.,  846 D) of the identified closest anchor, exclusive of the start value and end value, such as with anchor  846 B. 
     In accordance with some embodiments, the corresponding intermediate value (e.g.,  844 C) of the identified closest anchor is equal to the respective start value (e.g.,  844 C) or the respective end value of the identified closest anchor, such as with anchor  844 B. 
     In accordance with some embodiments, updating the value of the characteristic of the object based on the corresponding intermediate value of the identified closest anchor comprises updating the value of the characteristic of the object to be equal to the corresponding intermediate value of the identified closest anchor. 
     In accordance with some embodiments, the corresponding start value and the corresponding end value of the identified closest anchor are different. In accordance with some embodiments, the corresponding intermediate value of the identified closest anchor is the average of the corresponding start value and the corresponding end value. 
     In accordance with some embodiments, subsequent to updating display of the object in accordance with the subsequently updated value of the characteristic of the object, the device initiates a duration (e.g., a time period) during which received user input requests to manipulate the characteristic of the object do not affect the displayed characteristic of the object. This is helpful, for example, to give the user time to visually recognize that the object has moved to an intermediate value of the closest anchor. In accordance with some embodiments, subsequent to the duration, updating display of the object in accordance with user input requests received during the duration. 
     In accordance with some embodiments, the closest anchor is identified by identifying the closest zone once the document  842  stops scrolling (e.g., reaches a steady state). As illustrated in  FIG.  8 G , the distance from the subsequently updated value (indicated by the scroll value indicator  862 ) to the zone of anchor  844 B is the distance  852  (e.g., a distance of 0.03), while the distance from the subsequently updated value (indicated by the scroll value indicator  862 ) to the zone of anchor  846 B is the distance  850  (e.g., a distance of 0.07). In this example, anchor  844 B is identified as the closest anchor because the distance  852  (e.g., distance of 0.03) is less than the distance  850  (e.g., distance of 0.07). Thus, identifying the closest anchor comprises identifying the nearest of start values and end values of the anchor and the second anchor. 
     In accordance with some embodiments, the closest anchor is identified by identifying the closest intermediate value once the document  842  stops scrolling (e.g., reaches a steady state). As illustrated in  FIG.  8 H , the distance from the subsequently updated value (indicated by the scroll value indicator  862 ) to the intermediate value  844 C of anchor  844 B is the distance  856  (e.g., a distance of 0.33), while the distance from the subsequently updated value (indicated by the scroll value indicator  862 ) to the intermediate value  846 C of anchor  846 B is the distance  854  (e.g., a distance of 0.20). In this example, anchor  844 B is identified as the closest anchor because the distance  854  (e.g., distance of 0.20) is less than the distance  856  (e.g., distance of 0.33). For example, the device calculates a difference between the subsequently updated value of the characteristic of the object and the corresponding intermediate value of the first anchor, and calculates a difference between the subsequently updated value of the characteristic of the object and the corresponding intermediate value of the second anchor. The lesser of these values indicates the closest anchor. 
     In accordance with some embodiments, the device performs a haptic alert at the device (e.g., a mechanical or audible haptic alert) while updating display of the object in accordance with the subsequently updated value of the characteristic of the object. This provides an indicated to the user that the object is transitioning to the nearest anchor. 
     In accordance with some embodiments, the object is a document and the characteristic of the object is scroll position. Examples of a document include, but are not limited to: a message, a text message, a text message conversation, an email, a presentation, a spreadsheet, a user editable file (e.g., a word processing file), a user ineditable file (e.g., a PDF file), a webpage, a list of items (e.g., list of contacts, list of music, list of calendar events, list of messages, list of files, list of folders). The device analyzes at least a portion of the document, wherein analyzing at least the portion of the document comprises identifying locations within the document. In accordance with some embodiments, the locations within the document include one or more of: one or more page boundaries of at least the portion of the document, one or more paragraph boundaries of at least the portion of the document, and one or more keyword locations of at least the portion of the document. The device assigns anchors to some or all of the identified page boundaries, paragraph boundaries, and keyword locations of the document. 
     In accordance with some embodiments, the device accesses a first set of anchor points (e.g., anchor points indicate where anchors should go, such as at paragraphs and images). The device assigns respective anchors to the first set of anchor points. The device then detects a change in value of the characteristic of the object (e.g., the document has been scrolled), and in response to detecting the change in the value of the characteristic of the object, the device accesses a second set of anchor points (e.g., the document has scrolled and more anchors are required). The device assigns respective anchors to the second set of anchor points, wherein the first set of anchor points and the second set of anchor points are different. This is helpful, for example, where an object includes many anchor points that require anchors, but device memory is limited and assigning anchors to all the anchor points at one time strains the available device memory. 
     In accordance with some embodiments, the object is selected from the group consisting of a document and an image. Examples of a document include, but are not limited to: a message, a text message, a text message conversation, an email, a presentation, a spreadsheet, a user editable file (e.g., a word processing file), a user ineditable file (e.g., a PDF file), a webpage, a list of items (e.g., list of contacts, list of music, list of calendar events, list of messages, list of files, list of folders). In accordance with some embodiments, the characteristic of the object is selected from the group consisting of scroll position (e.g., how far up/down is the object scrolled), zoom size (e.g., how large/small is the document zoomed), and degree of rotation (e.g., how many radians is the object rotated). 
       FIG.  9 B  is a flow diagram illustrating an exemplary process for manipulating user interface objects in accordance with some embodiments. In some embodiments, method  920  may be performed at an electronic device with a display (e.g.,  112 ,  340 ,  504 ) and a rotatable input mechanism (e.g.,  506 ). Some operations in method  920  may be combined, the order of some operations may be changed, and some operations may be omitted. Exemplary devices that may perform method  920  include devices  100 ,  300 ,  500 , and/or  550  ( FIGS.  1 A,  3 ,  5 A, and  5 C ). 
     Method  920  provides an intuitive way to manipulate user interface objects. The method reduces the cognitive burden on a user when using a device to manipulate a user interface object, such as scrolling, zooming, or rotating an object, thereby creating a more efficient human-machine interface. For battery-operated computing devices, enabling a user to manipulate user interface objects more efficiently conserves power and increases the time between battery charges. 
     At block  922 , an object (e.g. document  842 ) is displayed in accordance with a value of a characteristic (e.g., scroll position value) of the object, the value being within a range of values (e.g., 0.0 to 1.0) of the characteristic. 
     At block  924 , a user input request is received. The user input request represents rotation of the rotatable input mechanism (e.g.,  506 ). 
     At block  926 , in response to receiving the user input request, blocks  928  and  930  are performed. At block  928 , the value of the characteristic of the object (e.g., document  842 ) is updated within the range of values (e.g., 0.0 to 1.0) of the characteristic based on the user input request. At block  930 , display of the object is updated in accordance with the updated value of the characteristic of the object (e.g., the document is scrolled and then reaches a stopped position, which is a steady state). 
     At block  932 , a closest anchor (e.g., anchor  844 B or  846 B) to the updated value of the characteristic of the object is identified, the closest anchor identified from among at least a first anchor (e.g.,  844 B) having a corresponding intermediate value (e.g.,  844 C) and a second anchor (e.g.,  846 B) having a corresponding intermediate value (e.g.,  846 C). 
     At block  934 , the value of the characteristic of the object is subsequently updated based on the corresponding intermediate value (e.g., value at  844 C or  846 C) of the identified closest anchor (e.g., anchor  844 B or  846 B). 
     At block  936 , display of the object (e.g., document  842 ) is updated in accordance with the subsequently updated value of the characteristic of the object. 
     In accordance with some embodiments, updating display of the object in accordance with the subsequently updated value of the characteristic of the object comprises animating the object to reflect the subsequently updated value of the characteristic of the object. 
     In accordance with some embodiments, the corresponding intermediate value of the identified closest anchor is between the respective start value (e.g.,  846 E) and the respective end value (e.g.,  846 D) of the identified closest anchor, exclusive of the start value and end value, such as with anchor  846 B. 
     In accordance with some embodiments, the corresponding intermediate value (e.g.,  844 C) of the identified closest anchor is equal to the respective start value (e.g.,  844 C) or the respective end value of the identified closest anchor, such as with anchor  844 B. 
     In accordance with some embodiments, updating the value of the characteristic of the object based on the corresponding intermediate value of the identified closest anchor comprises updating the value of the characteristic of the object to be equal to the corresponding intermediate value of the identified closest anchor. 
     In accordance with some embodiments, the corresponding start value and the corresponding end value of the identified closest anchor are different. In accordance with some embodiments, the corresponding intermediate value of the identified closest anchor is the average of the corresponding start value and the corresponding end value. 
     In accordance with some embodiments, subsequent to updating display of the object in accordance with the subsequently updated value of the characteristic of the object, the device initiates a duration (e.g., a time period) during which received user input requests to manipulate the characteristic of the object do not affect the displayed characteristic of the object. In accordance with some embodiments, subsequent to the duration, updating display of the object in accordance with user input requests received during the duration. 
     In accordance with some embodiments, the closest anchor is identified by identifying the closest zone once the document  842  stops scrolling (e.g., reaches a steady state). 
     In accordance with some embodiments, the closest anchor is identified by identifying the closest intermediate value once the document  842  stops scrolling (e.g., reaches a steady state). 
     In accordance with some embodiments, the device performs a haptic alert at the device (e.g., a mechanical or audible haptic alert) while updating display of the object in accordance with the subsequently updated value of the characteristic of the object. 
     In accordance with some embodiments, the object is a document and the characteristic of the object is scroll position. Examples of a document include, but are not limited to: a message, a text message, a text message conversation, an email, a presentation, a spreadsheet, a user editable file (e.g., a word processing file), a user ineditable file (e.g., a PDF file), a webpage, a list of items (e.g., list of contacts, list of music, list of calendar events, list of messages, list of files, list of folders). The device analyzes at least a portion of the document, wherein analyzing at least the portion of the document comprises identifying locations within the document. In accordance with some embodiments, the locations within the document include one or more of: one or more page boundaries of at least the portion of the document, one or more paragraph boundaries of at least the portion of the document, and one or more keyword locations of at least the portion of the document. The device assigns anchors to some or all of the identified page boundaries, paragraph boundaries, and keyword locations of the document. 
     In accordance with some embodiments, the device accesses a first set of anchor points (e.g., anchor points indicate where anchors should go, such as at paragraphs and images). The device assigns respective anchors to the first set of anchor points. The device then detects a change in value of the characteristic of the object (e.g., the document has been scrolled), and in response to detecting the change in the value of the characteristic of the object, the device accesses a second set of anchor points (e.g., the document has scrolled and more anchors are required). The device assigns respective anchors to the second set of anchor points, wherein the first set of anchor points and the second set of anchor points are different. 
     In accordance with some embodiments, the object is selected from the group consisting of a document and an image. Examples of a document include, but are not limited to: a message, a text message, a text message conversation, an email, a presentation, a spreadsheet, a user editable file (e.g., a word processing file), a user ineditable file (e.g., a PDF file), a webpage, a list of items (e.g., list of contacts, list of music, list of calendar events, list of messages, list of files, list of folders). In accordance with some embodiments, the characteristic of the object is selected from the group consisting of scroll position (e.g., how far up/down is the object scrolled), zoom size (e.g., how large/small is the document zoomed), and degree of rotation (e.g., how many radians is the object rotated). 
     In accordance with some embodiments, analysis of the object is not required to specify the anchors. For example, the anchors may be associated with the object (e.g., embedded in the document) prior to the object being accessed at the device. Such predefined anchors may be manually specified by the author of the object. 
     The anchors described in relation to  FIGS.  8  and  9 B  (e.g.,  844 B,  846 B) have the technical advantage of allowing coarse input to be translated to precise control. Certain portions of documents (or certain zoom sizes, certain degrees of rotation) can be made easier or more difficult to move to, facilitating the process of directing the user&#39;s focus. Further, the anchors of a particular object may have different properties, such as different size of ranges. The anchors can be used to direct the “flow” through a document to allow for curation. 
     Note that details of the processes described above with respect to method  920  ( FIG.  9 B ) are also applicable in an analogous manner to the methods described above and below. For example, method  920  may include one or more of the characteristics of the various methods described above with reference to the processes in  FIGS.  7 ,  9 A,  11 ,  13 K,  22 ,  31 ,  39 , and  46   . For brevity, these details are not repeated below. 
     It should be understood that the particular order in which the operations in  FIG.  11    have been described is exemplary and not intended to indicate that the described order is the only order in which the operations could be performed. One of ordinary skill in the art would recognize various ways to reorder the operations described herein, as well as excluding certain operations. For brevity, these details are not repeated here. Additionally, it should be noted that aspects of the methods and processes described throughout this description may be incorporated with one another. 
       FIGS.  10 A- 10 B  illustrate exemplary user interfaces for manipulating user interface objects using an electronic device (e.g.,  500 ), in accordance with some embodiments. In some embodiments, the electronic device is device  500 . The electronic device has a display (e.g.,  112 ,  340 ,  504 ) and a rotatable input mechanism (e.g.,  506 ). 
       FIGS.  10 A- 10 B  illustrates an instant messaging conversation  1002 , which is an example of user interface object. In some embodiments, the electronic device is configured to allow a user to scroll the object (e.g.,  1002 ), such that only a portion of the object is visible on the display (e.g.,  504 ) at a particular time. The scroll position of the object is a characteristic of the object. The value of the scroll position of the object changes as the object is scrolled. 
     The user interface figures described optionally include markers (e.g.,  1002 A,  1002 B,  1002 C). These markers are typically not part of the displayed user interface, but are provided to aid in the interpretation of the figures. In these examples, the markers illustrate scroll positions of the objects. 
       FIGS.  10 A- 10 B  also illustrate a viewable display area ( 1020 ) and a scroll value indicator (e.g.,  1022 ). The viewable display area encompasses an exemplary area identifying the displayed user interface. For example, display area  1020  illustrates the portion of the conversation  1002  that is displayed on the display when the conversation  1002  is scrolled using the rotatable input mechanism (e.g.,  506 ). The rotatable input mechanism  506  and the scroll value indicator (e.g.,  1022 ) help in the interpretation of the figures and are typically not part of the displayed user interface. 
       FIG.  10 A  illustrates a viewable portion of conversation  1002 , as illustrated by display area  1020 . The device displays, on the display, the object (e.g., conversation  1002 ). The object is associated with a first marker having a first value (e.g. marker  1002 A) and a second marker having a second value (e.g., marker  1002 B). A value (e.g., scroll position value) of a characteristic (e.g., scroll position) of the object is based on the first value of the first marker. 
     The device receives user input representing rotation of the rotatable input mechanism. In response to receiving the user input representing rotation of the rotatable input mechanism, the device determines whether an attribute of the user input (e.g., the speed, acceleration, duration of the user input) exceeds a threshold value (e.g., user input is above a threshold speed or threshold acceleration). In accordance with a determination that the attribute of the user input exceeds the threshold value (e.g., the user input exceeds a threshold velocity or exceeds a threshold acceleration), the device updates the value of the characteristic of the object (e.g.,  1002 ) based on the second value of the second marker. In some embodiments, the attribute is acceleration and the threshold is a threshold of acceleration of the rotatable input mechanism, wherein the input may be referred to as a “flicking” input. The device also updates display of the object in accordance with the updated value of the characteristic of the object. Thus, when the device determines that, for example, the user input on the rotatable input mechanism exceeds a threshold velocity, the device scrolls the document on the display to the next marker (e.g., from marker  1002 A to marker  1002 B). In some embodiments, the direction of the rotation of the input mechanism determines the direction of the scroll, and the second marker is the closest marker in the determined direction of the scroll. 
     In accordance with some embodiments, updating display of the object in accordance with the updated value of the characteristic of the object comprises animating the object to reflect the updated value of the characteristic of the object. For example, the device displays an animation of scrolling the conversation to the second marker. For another example, when the characteristic is a zoom size, the device displays an animation of zooming the object to the second marker. 
     In some embodiments, in accordance with a determination that the attribute of the user input is less than the threshold value (e.g., the user input does not exceed a threshold velocity or does not exceed a threshold acceleration), the device maintains display of the object in accordance with the value of the characteristic of the object based on the first value of the first marker (e.g., continue to display the object at the same position as before, or continue to display the object at the same zoom level as before). 
     In some embodiments, in accordance with a determination that the attribute of the user input does not exceed the threshold value (e.g., the user input does not exceed a threshold velocity or does not exceed a threshold acceleration), updating the value of the characteristic of the object to a third value, the third value based on the user input. Thus, if the input does not exceed the threshold value, the object is scrolled (or zoomed) to a location other than the second marker. Accordingly, when the user rotates the rotatable input mechanism without exceeding the threshold value, the device smoothly scrolls the object. 
     In accordance with some embodiments, the second marker is an anchor and the second value of the second marker is an intermediate value of the anchor. 
     In some embodiments, in accordance with a determination that the attribute of the user input exceeds the threshold value (e.g., the user input exceeds a threshold velocity or exceeds a threshold acceleration), the device performs a haptic alert (e.g., perform a mechanical or audible alert) at the electronic device. 
     In accordance with some embodiments, the object is a document. The device analyzes at least a portion of the document, wherein analyzing at least the portion of the document comprises identifying locations (e.g., locations to place markers) within the document. 
     In accordance with some embodiments, the locations within the document include one or more of: one or more page boundaries of at least the portion of the document, one or more paragraph boundaries of at least the portion of the document, and one or more keyword locations of at least the portion of the document. The device assigns markers to some or all of the identified page boundaries, paragraph boundaries, and keyword locations of the document. 
     In accordance with some embodiments, the device accesses a first set of markers of the object. The device detects a change in value of the characteristic of the object (e.g., the document has been scrolled). In response to detecting the change in the value of the characteristic of the object, the device associates a second set of markers to the object, wherein the first set and the second set are different. 
     In some embodiments, in accordance with a determination that the attribute of the user input does exceeds the threshold value (e.g., the user input exceeds a threshold velocity or exceeds a threshold acceleration), initiating a duration during which received user inputs representing rotation of the rotatable input mechanism do not affect the displayed characteristic of the object. 
     In accordance with some embodiments, the attribute of the user input is angular velocity of the rotatable input mechanism and the threshold value is a threshold angular velocity. In accordance with some embodiments, the attribute of the user input is a maximum angular velocity of the rotatable input mechanism and the threshold value is a threshold angular velocity. In accordance with some embodiments, the attribute of the user input is angular acceleration of the rotatable input mechanism and the threshold value is a threshold angular acceleration. 
     In accordance with some embodiments, the object is selected from the group consisting of a document and an image. Examples of a document include, but are not limited to: a message, a text message, a text message conversation, an email, a presentation, a spreadsheet, a user editable file (e.g., a word processing file), a user ineditable file (e.g., a PDF file), a webpage, a list of items (e.g., list of contacts, list of music, list of calendar events, list of messages, list of files, list of folders). 
     In accordance with some embodiments, the characteristic of the object is selected from the group consisting of scroll position (e.g., how far up/down is the object scrolled), zoom size (e.g., how large/small is the document zoomed), and degree of rotation (e.g., how many radians is the object rotated). 
       FIG.  11    is a flow diagram illustrating an exemplary process for manipulating user interface objects in accordance with some embodiments. In some embodiments, method  1100  may be performed at an electronic device with a display (e.g.,  112 ,  340 ,  504 ) and a rotatable input mechanism (e.g.,  506 ). Some operations in method  1100  may be combined, the order of some operations may be changed, and some operations may be omitted. Exemplary devices that may perform method  1100  include devices  100 ,  300 ,  500 , and/or  550  ( FIGS.  1 A,  3 ,  5 A, and  5 C ). 
     Method  1100  provides an intuitive way to manipulate user interface objects. The method reduces the cognitive burden on a user when using a device to manipulate a user interface object, such as scrolling, zooming, or rotating an object, thereby creating a more efficient human-machine interface. For battery-operated computing devices, enabling a user to manipulate user interface objects more efficiently conserves power and increases the time between battery charges. 
     At block  1102 , an object (e.g., instant message conversation  1002 ) is displayed, wherein the object (e.g., conversation  1002 ) is associated with a first marker (e.g.,  1002 A) having a first value and a second marker (e.g.,  1002 B) having a second value, and wherein a value (e.g., scroll position value or zoom size value) of a characteristic (e.g., scroll position or zoom size) of the object (e.g., conversation  1002 ) is based on the first value of the first marker. 
     At block  1104 , user input representing rotation of the rotatable input mechanism (e.g.,  506 ) is received. 
     At block  1106 , in response to receiving the user input representing rotation of the rotatable input mechanism, it is determined whether an attribute of the user input (e.g., the speed, acceleration, duration of the user input) exceeds a threshold value. 
     At block  1108 , in accordance with a determination that the attribute of the user input exceeds the threshold value (e.g., the user input exceeds a threshold velocity or exceeds a threshold acceleration), the value of the characteristic of the object is updated based on the second value of the second marker. 
     At block  1110 , display of the object is updated in accordance with the updated value of the characteristic of the object (e.g., the conversation is scrolled to the marker, as illustrated in  FIG.  10 B ). 
     In accordance with some embodiments, updating display of the object (e.g., conversation  1002 ) in accordance with the updated value of the characteristic of the object comprises animating the object to reflect the updated value of the characteristic of the object. 
     In some embodiments, in accordance with a determination that the attribute of the user input is less than the threshold value, the device maintains display of the object in accordance with the value of the characteristic of the object based on the first value of the first marker (e.g., the conversation is not scrolled). 
     In some embodiments, in accordance with a determination that the attribute of the user input does not exceed the threshold value (e.g., the user input does not exceed a threshold velocity or does not exceed a threshold acceleration), updating the value of the characteristic of the object to a third value, the third value based on the user input. Thus, if the input does not exceed the threshold value, the object is scrolled (or zoomed) to a location other than the second marker. 
     In accordance with some embodiments, the second marker (e.g.,  1002 B) is an anchor and the second value of the second marker is an intermediate value of the anchor. 
     In some embodiments, in accordance with a determination that the attribute of the user input exceeds the threshold value (e.g., the user input exceeds a threshold velocity or exceeds a threshold acceleration), the device performs a haptic alert (e.g., perform a mechanical or audible alert) at the electronic device. 
     In accordance with some embodiments, the object is a document. The device analyzes at least a portion of the document, wherein analyzing at least the portion of the document comprises identifying locations (e.g., locations to place markers) within the document. 
     In accordance with some embodiments, the locations within the document include one or more of: one or more page boundaries of at least the portion of the document, one or more paragraph boundaries of at least the portion of the document, and one or more keyword locations of at least the portion of the document. The device assigns markers to some or all of the identified page boundaries, paragraph boundaries, and keyword locations of the document. 
     In accordance with some embodiments, the device accesses a first set of markers of the object. The device detects a change in value of the characteristic of the object (e.g., the document has been scrolled). In response to detecting the change in the value of the characteristic of the object, the device associates a second set of markers to the object, wherein the first set and the second set are different. 
     In some embodiments, in accordance with a determination that the attribute of the user input does exceeds the threshold value (e.g., the user input exceeds a threshold velocity or exceeds a threshold acceleration), initiating a duration during which received user inputs representing rotation of the rotatable input mechanism do not affect the displayed characteristic of the object. 
     In accordance with some embodiments, the attribute of the user input is angular velocity of the rotatable input mechanism and the threshold value is a threshold angular velocity. In accordance with some embodiments, the attribute of the user input is a maximum angular velocity of the rotatable input mechanism and the threshold value is a threshold angular velocity. In accordance with some embodiments, the attribute of the user input is angular acceleration of the rotatable input mechanism and the threshold value is a threshold angular acceleration. 
     In accordance with some embodiments, the object is selected from the group consisting of a document and an image. Examples of a document include, but are not limited to: a message, a text message, a text message conversation, an email, a presentation, a spreadsheet, a user editable file (e.g., a word processing file), a user ineditable file (e.g., a PDF file), a webpage, a list of items (e.g., list of contacts, list of music, list of calendar events, list of messages, list of files, list of folders). 
     In accordance with some embodiments, the characteristic of the object is selected from the group consisting of scroll position (e.g., how far up/down is the object scrolled), zoom size (e.g., how large/small is the document zoomed), and degree of rotation (e.g., how many radians is the object rotated). 
     In accordance with some embodiments, analysis of the object is not required to specify the markers. For example, the markers may be associated with the object (e.g., embedded in the document) prior to the object being accessed at the device. Such predefined markers may be manually specified by the author of the object. 
     The markers described in relation to  FIGS.  10  and  11    (e.g.,  1002 A,  1002 B,  1002 C) have the technical advantage of allowing coarse input to be translated to precise control. Certain portions of documents (or certain zoom sizes, certain degrees of rotation) can be made easier or more difficult to move to, facilitating the process of directing the user&#39;s focus. Further, the markers of a particular object may have different properties, such as different thresholds to move to them. The markers can be used to direct the “flow” through a document to allow for curation. 
     Note that details of the processes described above with respect to method  1100  ( FIG.  11   ) are also applicable in an analogous manner to the methods described above and below. For example, method  1100  may include one or more of the characteristics of the various methods described above with reference to the processes in  FIGS.  7 ,  9 A,  9 B,  13 K,  22 ,  31 ,  39 , and  46   . For brevity, these details are not repeated below. 
     It should be understood that the particular order in which the operations in  FIG.  11    have been described is exemplary and not intended to indicate that the described order is the only order in which the operations could be performed. One of ordinary skill in the art would recognize various ways to reorder the operations described herein, as well as excluding certain operations. For brevity, these details are not repeated here. Additionally, it should be noted that aspects of the methods and processes described throughout this description may be incorporated with one another. 
       FIG.  12    shows exemplary functional blocks of an electronic device  1200  that, in some embodiments, perform the features described above and below. As shown in  FIG.  12   , an electronic device  1200  includes a display unit  1202  configured to display graphical objects; a touch-sensitive surface unit  1204  configured to receive user gestures (e.g., touches); one or more RF units  1206  configured to detect and communicate with external electronic devices; and a processing unit  1208  coupled to display unit  1202 , touch-sensitive surface unit  1204 , and RF units  1206 . In some embodiments, the processing unit  1208  includes a display enabling unit  1210 , a receiving unit  1212 , and a determining unit  1214 . The units of  FIG.  12    may be used to implement the various techniques and methods described above and below. 
     For example, the display enabling unit  1210  can be used for: displaying, on the display, an object in accordance with a value of a characteristic of the object, the value being within a range of values of the characteristic; displaying, on the display, an object in accordance with a value of a characteristic of the object, the value being within a range of values of the characteristic; displaying, on the display, an object in accordance with a value of a characteristic of the object, the value being within a range of values of the characteristic; displaying, on the display, an object, wherein the object is associated with a first marker having a first value and a second marker having a second value. 
     For example, the receiving unit  1212  can be used for: receiving a user input request, the user input request representing rotation of the rotatable input mechanism; receiving a user input request, the user input request representing rotation of the rotatable input mechanism; receiving a user input request, the user input request representing rotation of the rotatable input mechanism; receiving user input representing rotation of the rotatable input mechanism. 
     For example, the determining unit  1214  can be used for: determining whether the value of the characteristic of the object is within a predetermined subset of the range of values of the characteristic; determining whether the user input request causes the value of the characteristic of the object to transition into range of a zone of an anchor, determining whether an attribute of the user input exceeds a threshold value; 
     For example, the updating unit  1216  can be used for: updating the value of the characteristic of the object within the range of values of the characteristic based on the user input request and in accordance with a first function; updating the value of the characteristic of the object within the range of values of the characteristic based on the user input request and in accordance with a second function, wherein the first function and the second function are different functions; updating display of the object in accordance with the updated value of the characteristic of the object; updating the value of the characteristic of the object based on the intermediate value of the anchor; updating display of the object in accordance with the updated value of the characteristic of the object; updating the value of the characteristic of the object within the range of values of the characteristic based on the user input request; updating display of the object in accordance with the updated value of the characteristic of the object; subsequently updating the value of the characteristic of the object based on the corresponding intermediate value of the identified closest anchor; updating display of the object in accordance with the subsequently updated value of the characteristic of the object; updating the value of the characteristic of the object based on the second value of the second marker; and updating display of the object in accordance with the updated value of the characteristic of the object. 
     The functional blocks of the device  1200  are, optionally, implemented by hardware, software, or a combination of hardware and software to carry out the principles of the various described examples. It is understood by persons of skill in the art that the functional blocks described in  FIG.  12    are, optionally, combined or separated into sub-blocks to implement the principles of the various described examples. Therefore, the description herein optionally supports any possible combination or separation or further definition of the functional blocks described herein. 
       FIGS.  13 A- 13 J  illustrate an exemplary user interface  1300  displaying multiple user interface objects in the form of selectable elements  1302 ,  1304 ,  1306 ,  1308  and a focus selector  1310 . A user can select a selection element from among the multiple selectable elements by using a physical crown of a wearable electronic device to move the focus selector  1310  to align with the desired selection element. 
     Crown  558  of device  550  is a user rotatable user interface input (e.g., a rotatable input mechanism). The crown  558  can be turned in two distinct directions: clockwise and counterclockwise.  FIGS.  13 - 13 J  include rotation direction arrows illustrating the direction of crown rotation and movement direction arrows illustrating the direction of movement of one or more user interface objects, where applicable. The rotation direction arrows and movement direction arrows are typically not part of the displayed user interface, but are provided to aid in the interpretation of the figures. In this example, a clockwise direction rotation of crown  558  is illustrated by a rotation direction arrow pointing in the up direction. Similarly, a counterclockwise direction rotation of crown  558  is illustrated by a rotation direction arrow pointing in the down direction. The characteristics of the rotation direction arrow are not indicative of the distance, speed, or acceleration with which crown  558  is rotated by a user. Instead, the rotation direction arrow is indicative of the direction of rotation of crown  558  by the user. 
       FIGS.  13 - 13 J  illustrate an exemplary physics-based model that can be used to control a user&#39;s interactions with user interface objects in conjunction with a physical crown user input device. In this example, elements  1302 ,  1304 ,  1306 ,  1308  are stationary and the focus selector  1310  is movable via user input received from crown  558 . Clockwise movement of crown  558  is associated with a force on the focus selector  1310  in the up movement direction and counterclockwise movement of crown  558  is associated with a force on the focus selector  1310  in the down movement direction. Accordingly, moving the focus selector  1310  from a position aligned with element  1306 , as shown in  FIG.  13 A , to align with element  1304  located in the up direction, as shown in  FIG.  13 J , requires a user input on the crown  558  in the clockwise direction. 
     To facilitate a user&#39;s ability to control the movement of focus selector  1310  among the four user-selectable elements  1302 ,  1304 ,  1306 ,  1308 , a “magnetic” relationship is associated between each user selectable element and the focus selector  1310 . Each element  1302 ,  1304 ,  1306 ,  1308  is associated with a simulated magnetic value. In this example, the magnetic values of elements  1302 ,  1304 ,  1306 ,  1308  are equal. In other examples, the magnetic values of elements  1302 ,  1304 ,  1306 ,  1308  may not be equal. 
     Using the magnetic relationship between the elements  1302 ,  1304 ,  1306 ,  1308  and focus selector  1310 , physics-based modeling can be used to simulate magnetic attraction between elements  1302 ,  1304 ,  1306 ,  1308  and focus selector  1310 . As will be described in further detail below, user interface  1300  causes an attraction between elements  1302 ,  1304 ,  1306 ,  1308  and focus selector  1310 . As a result, when user input is not received, focus selector  1310  ultimately reaches a steady state where it is aligned with one of elements  1302 ,  1304 ,  1306 ,  1308 . An object is in a steady state when the object is not being translated, rotated, or scaled. The alignment of focus selector  1310  with the element allows the element to be activated using a user input. Even before any user input for activation, alignment of focus selector  1310  with the element is indicative of the selection of that element. This physics-based magnetic modeling results in the user interface exhibiting virtual detents. 
     In this example, physics-based magnetic modeling is achieved, for example, by modeling each element  1302 ,  1304 ,  1306 ,  1308  as an object made from a magnetized material that creates its own persistent magnetic field and modeling focus selector  1310  as a material that is attracted to a magnet, such as ferromagnetic materials including iron, cobalt, and nickel. In another example, the physics-based modeling can be achieved by modeling each element  1302 ,  1304 ,  1306 ,  1308  as an object made from a material that is attracted to a magnet and modeling focus selector  1310  as a material that creates its own persistent magnetic field. In another example, the physics-based modeling can be achieved by modeling each element  1302 ,  1304 ,  1306 ,  1308  as an object that creates its own persistent magnetic field and modeling focus selector  1310  as a material that also creates its own persistent magnetic field, such as two magnets that attract. Each of these physics-based models can be adapted to include magnetic fields that vary, rather than remain persistent, based on certain factors, such as the distance between the element and focus selector  1310 , the speed of focus selector  1310 , the acceleration of focus selector  1310 , or based on a combination of two or more factors. For example, the varying magnetic field may be simulated through the use of an electromagnet which can be turned on and off and can have a varying strength. 
     At  FIG.  13 A , focus selector  1310  is aligned with element  1306 , indicating selection of element  1306 . At  FIG.  13 B , device  550  determines a change in the position of crown  558  in the clockwise direction, as indicated by rotation direction arrow  1312 . In response to determining the change in the position of the crown  558 , the device increases the speed of focus selector  1310 , moving focus selector  1310  in the up direction, as indicated by movement direction arrow  1314 . In one example, focus selector  1310  may be associated with a mass or may have a calculated inertia. 
     Because element  1306  is modeled as a magnetic element and focus selector  1310  is modeled as a ferromagnetic material, there is a magnetic attraction between the two user interface objects. The physics-based model of user interface  1300  causes a resistance of the movement of focus selector  1310  away from element  1306  using this magnetic attraction. An element&#39;s magnetic value (e.g., the strength of an element&#39;s magnet attraction) may be modeled, for example, in terms of its pull force (the elements ability to move other objects). The pull force exerted may be based on the pull force of either an electromagnet or a permanent magnet as described by the Maxwell equation. 
     At  FIGS.  13 C- 13 D , device  550  continues to determine a change in the position of crown  558  in the clockwise direction, as indicated by rotation direction arrow  1316 . In response to determining the change in the position of the crown  558 , the device  550  adds additional speed to the focus selector  1310  in the up direction. At the same time, the magnetic attraction of elements  1302 ,  1304 ,  1306 , and  1308  are acting on focus selector  1310 . At  FIG.  13 C , elements  1306  and  1308  are applying a force to the focus selector  1310  in the down direction as a result of the physics-based magnetic modeling. Elements  1302  and  1304  are applying a force to focus selector  1310  in the up direction as a result of the physics-based magnetic modeling. 
     The distance between each element and focus selector  1310  also play a role in the amount of force the element applies to focus selector  1310 . Generally, as the distance between the element and the focus selector  1310  increases, the intensity of the force between the element and the focus selector  1310  decreases. The rate of change in the intensity of the force can be modeled in many ways. For example, the inverse square law may apply the intensity of the force as a function of the distance. More specifically, I=1/d2, where I is the intensity of the force and d is the distance. In other examples, the magnetic force can vary in direct inverse proportion to distance or can vary inversely with the third power of distance. 
     In some examples, the magnetic attraction between an element and a focus selector only exists while the focus selector is within an attraction area having an outer edge that is a predetermined distance from the element. This simplifies calculations because the magnetic force of elements with a distance from the focus selector that is greater than a predetermined distance are not considered in determining the forces applied to the focus selector. 
     In some examples, to add additional realism and provide further ease of usability to the user interface, the system may also employ a physics-based model of friction to reduce the speed of the focus selector while the focus selector is in motion. For example, the speed of the focus selector can be continuously (or repeatedly) decreased based on a friction coefficient value. This physics-based friction model may simulate kinetic friction, drag friction, or the like. 
     At  FIG.  13 D , focus selector  1310  is directly between elements  1302 ,  1304  and elements  1306 ,  1308 . However, focus selector  1310  continues to move in the up direction based in part on the speed or inertia associated with focus selector  1310 . 
     At  FIGS.  13 E- 13 J , device  550  determines that there is no change in the position of crown  558 . As a result of this determination, no additional speed is added to the existing speed of focus selector  1310 . However, the magnetic forces of elements  1302 ,  1304 ,  1306 ,  1308  continue to be applied, as well as the physics-based friction model. At  FIGS.  13 E- 13 J , element  1304  has the largest magnetic effect on focus selector  1310 , as compared to elements  1302 ,  1306 ,  1308 , because element  1304  is the closest to focus selector  1310 . This physics-based magnetic modeling results in the user interface exhibiting virtual detents. 
     In  FIGS.  13 E- 13 F , element  1304  applies a magnetic force on focus selector  1310  in the up direction. At  FIGS.  13 G- 13 H , as focus selector  1310  overshoots element  1304 , element  1304  applies a force on focus selector  1310  in the down direction, further reducing the speed of focus selector  1310  until focus selector  1310  reaches a momentary stop at  FIG.  13 H . At  FIG.  13 I , the magnetic force applied by element  1304  on focus selector  1310  in the down direction causes focus selector  1310  to move down and align with element  1304 . At  FIG.  13 J , focus selector  1310  comes to rest while aligned with element  1304 . The system interprets this alignment as a selection of element  1304 , which is achieved by the user manipulating focus selector  1310  through the use of crown  558 . 
     While element  1304  is selected, the user can activate element  1304  by one or more techniques. For example, the user may press on touch-sensitive display  556 , press on the touch-sensitive display with force above a predetermined threshold, press button  562 , or simply allow element  1304  to remain selected for a predetermined amount of time. In another example, aligning an element and a focus selector can be interpreted as both a selection and an activation of the element. 
     In this example, movement of focus selector  1310  is constrained along a predefined vertical path. In other examples, movement of the focus selector may be constrained along a different predefined path, or may not be constrained to a predefined path. In this example, alignment in only one axis (the vertical axis) is used to indicate selection of an element. In some examples, alignment in two, three, or more axes may be required between an element and a focus selector to indicate a selection. 
       FIG.  13 K  is a flow diagram illustrating a process  1350  for selecting an element in a graphical user interface using a physical crown as an input device. Process  1350  is performed at a wearable electronic device (e.g., device  550  in  FIG.  1   ) having a physical crown. In some examples, the electronic device also includes a touch-sensitive display. The process provides an efficient technique for selecting an element from among multiple elements in a graphical user interface. 
     At block  1352 , the device causes a display of a plurality of selectable elements on a touch-sensitive display of a wearable electronic device. The device also causes a display of a focus selector. The device uses a physics-based model to simulate magnetic attraction between the selectable elements and the focus selector. Each selectable element of the plurality of selectable elements is associated with a corresponding magnetic value. The magnetic value can be the strength of an element&#39;s magnet attraction in terms of its pull force. 
     In some examples, the system causes the plurality of selectable elements to be displayed linearly and equidistantly. This configuration adds additional ease of selection of the elements by the user. This configuration is especially beneficial when the selectable elements have equal importance and are therefore weighted equally. 
     At block  1354 , the device receives crown position information. The crown position information may be received as a series of pulse signals, real values, integer values, and the like. 
     At block  1356 , the device determines whether a change has occurred in a crown distance value. The crown distance value is based on an angular displacement of the physical crown of the wearable electronic device. A change in the crown distance value is indicative of a user providing input to the wearable electronic device by, for example, turning the physical crown. If the device determines that a change in the crown distance value has not occurred, the system returns to block  1354  and continues receiving crown position information. If the device determines that a change in the crown distance value has occurred, the system continues to block  1358 , though the system may continue to receive crown position information. 
     The device also determines a direction based on a direction of rotation of the physical crown of the wearable electronic device. For example, an up direction can be determined based on a clockwise rotation of the physical crown. Similarly, a down direction can be determined based on a counterclockwise rotation of the physical crown. In other examples, a down direction can be determined based on a clockwise rotation of the physical crown and an up direction can be determined based on a counterclockwise rotation of the physical crown. 
     At block  1358 , in response to determining the change in the crown distance value, the devices causes a movement of the focus selector toward a selection element of the plurality of selectable elements. This movement changes the focus of the plurality of selectable elements. At least initially, the movement of the focus selector is in the determined direction. The movement of the focus selector may be animated. The movement has a rate of movement (speed). The system causes the rate of movement of the focus selector to change using the physics-based magnetic interaction of the focus selector with the selection element based at least on the magnetic value associated with the selection element. For example, the physics-based magnetic attraction of the selection element may cause the rate of movement of the focus selector to increase as the focus selector moves towards the selection element. Similarly, the physics-based magnetic attraction of the selection element may cause the rate of movement of the focus selector to decrease as the focus selector moves away from the selection element. 
     Similarly, the magnetic interaction of the focus selector with other selectable elements may cause a change in the rate of the movement of the focus selector. For example, the rate of the movement of the focus selector may change as it approaches and passes an element that remains unselected. The change in the rate of the movement of the focus selector resulting from this interaction with the unselected element is based at least in part on the magnetic value of the unselected element. 
     In some examples, the magnetic values associated with the selectable elements are virtual magnetic strengths based on a virtual pull force. 
     In some examples, to add additional realism and provide further ease of usability to the user interface, the system may employ a physics-based model of friction to reduce the rate of movement of the focus selector while it is in motion. For example, the rate of movement of the focus selector can be continuously (or repeatedly) decreased based on a friction coefficient value. This physics-based friction model may simulate kinetic friction, drag friction, or the like. 
     In some examples, the device receives an additional input through the rotation of the crown before the focus selector reaches a steady state. An object is in a steady state when the object is not being translated, rotated, or scaled. In this example, the system determines a second change in the crown distance value. The system also determines a second direction, which is based on the direction of rotation of the physical crown of the wearable electronic device. In response to determining the second change in the crown distance value, the system increases or decreases the rate of movement of the focus selector. The change in the rate of the movement of the focus selector is based on the second change in the crown distance value and the second direction. 
     In some examples, once the focus selector aligns with the selection element and is in a steady state, the system determines that the selection element has been selected. 
       FIGS.  14 - 21    illustrate an exemplary user interface  1400  displaying multiple user interface objects in the form of selectable elements  1402 ,  1404 ,  1406 ,  1408  and a focus selector  1410 . A user can select a selection element from among the multiple selectable elements by using a physical crown of a wearable electronic device to move the focus selector  1410  to align with desired selection element. An additional input from the user can be used to activate the selection element that is selected. 
     Crown  558  of device  550  is a user rotatable user interface input (e.g., a rotatable input mechanism). Crown  558  can be turned in two distinct directions: clockwise and counterclockwise.  FIGS.  14 - 20    include rotation direction arrows illustrating the direction of crown rotation and movement direction arrows illustrating the direction of movement of one or more user interface objects, where applicable. The rotation direction arrows and movement direction arrows are typically not part of the displayed user interface, but are provided to aid in the interpretation of the figures. In this example, a clockwise direction rotation of crown  558  is illustrated by a rotation direction arrow pointing in the up direction. Similarly, a counterclockwise direction rotation of crown  558  is illustrated by a rotation direction arrow pointing in the down direction. The characteristics of the rotation direction arrow are not indicative of the distance, speed, or acceleration with which crown  558  is rotated by a user. Instead, the rotation direction arrow is indicative of the direction of rotation of crown  558  by the user. 
       FIGS.  14 - 21    illustrate an exemplary physics-based model that can be used to control a user&#39;s interactions with user interface objects in conjunction with a physical crown user input device. In this example, the elements  1402 ,  1404 ,  1406 ,  1408  are stationary and the focus selector  1410  is movable via user input received from crown  558 . Clockwise movement of crown  558  is associated with a force on the focus selector  1410  in the up movement direction and counterclockwise movement of crown  558  is associated with a force on the focus selector  1410  in the down movement direction. 
     To facilitate a user&#39;s ability to control the movement of focus selector  1410  among the four user-selectable elements  1402 ,  1404 ,  1406 ,  1408 , a “magnetic” relationship is associated between each user selectable element and the focus selector  1410 . Each element  1402 ,  1404 ,  1406 ,  1408  is associated with a magnetic value. In this example, the magnetic values of elements  1302 ,  1304 ,  1306 ,  1308  are not all equal. Unequal magnetic values may be helpful for allowing a user to more easily select particular options. For example, if the system expects that 90% of the time a user will select a particular option from among multiple options, the magnetic value of the particular option may be configured to be significantly higher than the magnetic value of the other multiple options. This allows the user to quickly and easily select the particular option, while requiring more precise navigation of the user interface by the user to select one of the other multiple options. 
     In this example, the magnetic value of element  1402  is equal to the magnetic value of element  1404 . This is illustrated in  FIGS.  14 - 21    by the equal size of elements  1402  and  1404 . The magnetic value of element  1406  is less than the magnetic value of element  1404 . This is illustrated in  FIGS.  14 - 21    by the reduced size of element  1406 . The magnetic value of element  1408  is larger than the magnetic value of element  1404 . This is illustrated in  FIGS.  14 - 21    by the larger size of element  1408 . Thus, in this example, the magnetic strength of each of the elements  1402 ,  1404 ,  1406 ,  1408  is represented in  FIGS.  14 - 21    by the relative size of the elements  1402 ,  1404 ,  1406 ,  1408 . 
     Using the magnetic relationship between the elements  1402 ,  1404 ,  1406 ,  1408  and focus selector  1410 , physics-based modeling can be used to simulate magnetic attraction between elements  1402 ,  1404 ,  1406 ,  1408  and focus selector  1410 . As will be described in further detail below, user interface  1400  causes an attraction between elements  1402 ,  1404 ,  1406 ,  1408  and focus selector  1410 . As a result, when user input is not received, focus selector  1410  ultimately reaches a steady state where it is aligned with one of elements  1402 ,  1404 ,  1406 ,  1408 . An object is in a steady state when the object is not being translated, rotated, or scaled. The alignment of focus selector  1410  with the element is indicative of the selection of that element. In other examples, additional input, such as tapping, pressing the crown or another button may be required for selection. This physics-based magnetic modeling results in the user interface exhibiting virtual detents. 
     In this example, physics-based magnetic modeling is achieved by modeling each element  1402 ,  1404 ,  1406 ,  1408  as an object made from a magnetized material that creates its own persistent magnetic field and modeling focus selector  1410  as a material that is attracted to a magnet, such as ferromagnetic materials including iron, cobalt, and nickel. Other physics-based models can be used, such as those described above. 
     In this example, the magnetic strength of the elements  1402 ,  1404 ,  1406 ,  1408  are not all the same, as described above. Further, the magnetic strength of elements  1402 ,  1404 ,  1406 ,  1408  vary based on the speed of focus selector  1410 . The higher the speed of focus selector  1410 , the lower the magnetic strength of elements  1402 ,  1404 ,  1406 ,  1408 . The lower the speed of focus selector  1410 , the higher the magnetic strength of elements  1402 ,  1404 ,  1406 ,  1408 . As a result, when focus selector  1410  is moving quickly, the elements  1402 ,  1404 ,  1406 ,  1408  play a reduced role in changing the speed of the focus selector as compared to when focus selector  1410  is moving slowly. 
     The technique of varying the magnetic strength of elements  1402 ,  1404 ,  1406 ,  1408  is illustrated in  FIGS.  14 - 21   . The magnetic strength (and in this example, the size) of elements  1402 ,  1404 ,  1406 ,  1408  is based on the speed of focus selector  1410 . For example, the varying magnetic strengths may be simulated through the use of electromagnets which can have varying strengths. 
     At  FIG.  14   , focus selector  1410  is aligned with element  1404 , indicating selection of element  1404 . In some examples, additional input, such as tapping, pressing the crown or another button may be required for selection. At  FIG.  15   , device  550  determines a change in the position of crown  558  in the counterclockwise direction, as indicated by rotation direction arrow  1430 . In response to determining the change in the position of the crown  558 , the device increases the speed of focus selector  1410 , moving the focus selector  1410  in the down direction, as indicated by movement direction arrow  1420 . In one example, the focus selector may be associated with a mass or may have a calculated inertia. 
     Because element  1406  is modeled as a magnetic element and focus selector  1410  is modeled as a ferromagnetic material, there is a magnetic attraction between the two user interface objects. An element&#39;s magnetic value (e.g., the strength of an element&#39;s magnet attraction) may be modeled, for example, in terms of its pull force (the elements ability to move other objects). The pull force exerted may be based on the pull force of either an electromagnet or a permanent magnet as described by the Maxwell equation. 
     However, the magnetic strength of elements  1402 ,  1404 ,  1406 ,  1408  is based on the speed of the focus selector  1410 . The faster the focus selector  1410  is moving, the smaller the magnetic strengths of elements  1402 ,  1404 ,  1406 ,  1408 . This is illustrated in  FIGS.  15 - 17   . As the focus selector  1410  speeds up, elements  1402 ,  1404 ,  1406 ,  1408  lose their magnetic strength. This loss of magnetic strength is depicted in  FIGS.  15 - 17    with the reduced size of elements  1402 ,  1404 ,  1406 ,  1408  for illustrative purposes. Generally, the size of elements and focus selectors do not visually change with changes to their magnetic strength. 
     At  FIGS.  18 - 20   , focus selector  1410  slows down. The slower the focus selector  1410  is moving, the larger the magnetic strengths of elements  1402 ,  1404 ,  1406 ,  1408 . This is illustrated in  FIGS.  18 - 20   . As the focus selector  1410  slows down, elements  1402 ,  1404 ,  1406 ,  1408  regain their magnetic strength. This regain of magnetic strength is depicted in  FIGS.  18 - 20    with the increased size of elements  1402 ,  1404 ,  1406 ,  1408  for illustrative purposes. Generally, the size of elements and focus selectors do not visually change with changes to their magnetic strength. To summarize, the magnetic strength of the elements is inversely related to the speed of the focus selector. 
     As before, the distance between each element  1402 ,  1404 ,  1406 ,  1408  and focus selector  1410  also plays a role in the amount of force the elements apply to focus selector  1410 . 
     In some examples, the magnetic attraction between an element and a focus selector only exists while the focus selector is within an attraction area having an outer edge that is a predetermined distance from the element. This simplifies calculations because the magnetic force of elements with a distance from the focus selector that is greater than a predetermined distance are not considered in determining the forces applied to the focus selector. 
     In some examples, to add additional realism and provide further ease of usability to the user interface, the system may also employ a physics-based model of friction to reduce the speed of the focus selector while it is in motion. For example, the speed of the focus selector can be continuously (or repeatedly) decreased based on a friction coefficient value. This physics-based friction model may simulate kinetic friction, drag friction, or the like. 
     At  FIGS.  19 - 20   , the magnetic force applied by element  1408  on focus selector  1410  in the down direction causes focus selector  1410  to move down and align with element  1408 . At  FIG.  21   , focus selector  1410  comes to rest while aligned with element  1408 . The system interprets this alignment as a selection of element  1408 , which is achieved by the user manipulating focus selector  1410  through the use of crown  558 . In some examples, additional input, such as tapping, pressing the crown or another button may be required for selection. Further user input can be used to activate the selection. 
     While element  1408  is selected, the user can activate element  1408  by one or more of many techniques. For example, the user may press on the touch-sensitive display of the device, press on the touch-sensitive display with force above a predetermined threshold, press a button, or simply allow element  1408  to remain selected for a predetermined amount of time. In another example, aligning an element and a focus selector can be interpreted as both a selection and an activation of the element. 
     In this example, movement of the focus selector is constrained along a predefined vertical path. In other examples, movement of the focus selector may be constrained along a different predefined path, or may not be constrained to a predefined path. In this example, alignment in only one axis (the vertical axis) is used to indicate selection of an element. In some examples, alignment in two, three, or more axes may be required between an element and a focus selector to indicate a selection. In some examples, additional input, such as tapping, pressing the crown or another button after the alignment may be required for selection. 
       FIG.  22    is a flow diagram illustrating a process  2200  for selecting an element in a graphical user interface using a physical crown as an input device. Process  2200  is performed at a wearable electronic device (e.g., device  550  in  FIG.  1   ) having a physical crown. In some examples, the electronic device also includes a touch-sensitive display. The process provides an efficient technique for selecting an element from among multiple elements in a graphical user interface. 
     At block  2202 , the device causes a display of a plurality of selectable elements on a touch-sensitive display of a wearable electronic device. The device also causes a display of a focus selector. The device uses a physics-based model to simulate magnetic attraction between the selectable elements and the focus selector. Each selectable element of the plurality of selectable elements is associated with a corresponding magnetic value. The magnetic value can be the strength of an element&#39;s magnet attraction in terms of its pull force, and each element can have a different magnetic value. 
     At block  2204 , the device receives crown position information. The position information may be received as a series of pulse signals, real values, integer values, and the like. 
     At block  2206 , the device determines whether a change has occurred in a crown distance value. The crown distance value is based on an angular displacement of the physical crown of the wearable electronic device. A change in the crown distance value is indicative of a user providing input to the wearable electronic device by, for example, turning the physical crown. If the device determines that a change in the crown distance value has not occurred, the system returns to block  2204  and continues receiving crown position information. If the device determines that a change in the crown distance value has occurred, the system continues to block  2208 , though the system may continue to receive crown position information. 
     The device also determines a direction based on a direction of rotation of the physical crown of the wearable electronic device. For example, an up direction can be determined based on a clockwise rotation of the physical crown. Similarly, a down direction can be determined based on a counterclockwise rotation of the physical crown. In other examples, a down direction can be determined based on a clockwise rotation of the physical crown and an up direction can be determined based on a counterclockwise rotation of the physical crown. 
     At block  2208 , in response to determining the change in the crown distance value, the device causes a movement of the focus selector toward a selection element of the plurality of selectable elements. This movement changes the focus of the plurality of selectable elements. At least initially, the movement of the focus selector is in the determined direction. The movement of the focus selector may be animated. The movement has a rate of movement (speed). 
     In some examples, a minimum angular velocity of crown rotation that is necessary for the focus selector to reach an escape velocity corresponds directly to the instantaneous angular velocity of crown  558  ( FIG.  1   ), meaning that the user interface of device  550 , in essence, responds when crown  558  reaches a sufficient angular velocity. In some embodiments, the minimum angular velocity of crown rotation necessary for reaching the escape velocity is a calculated velocity that is based on, but not directly equal to, the instantaneous (“current”) angular velocity of crown  558 . In these examples, device  550  can maintain a calculated crown (angular) velocity V in discrete moments in time T according to equation 1:
 
 VT=V ( T− 1)+Δ V CROWN−Δ V DRAG.  (EQ. 1)
 
     In equation 1, VT represents a calculated crown velocity (speed and direction) at time T, V(T−1) represents the previous velocity (speed and direction) at time T−1, ΔVCROWN represents the change in velocity caused by the force being applied through the rotation of the crown at time T, and ΔVDRAG represents the change in velocity due to a drag force. The force being applied, which is reflected through ΔVCROWN, can depend on the current velocity of angular rotation of the crown. Thus, ΔVCROWN can also depend on the current angular velocity of the crown. In this way, device  550  can provide user interface interactions based not only on instantaneous crown velocity but also based on user input in the form of crown movement over multiple time intervals, even if those intervals are finely divided. Note, typically, in the absence of user input in the form of ΔVCROWN, VT will approach (and become) zero based on ΔVDRAG in accordance with EQ. 1, but VT would not change signs without user input in the form of crown rotation (ΔVCROWN). 
     Typically, the greater the velocity of angular rotation of the crown, the greater the value of ΔVCROWN will be. However, the actual mapping between the velocity of angular rotation of the crown and ΔVCROWN can be varied depending on the desired user interface effect. For example, various linear or non-linear mappings between the velocity of angular rotation of the crown and ΔVCROWN can be used. 
     Also, ΔVDRAG can take on various values. For example, ΔVDRAG can depend on the velocity of crown rotation such that at greater velocities, a greater opposing change in velocity (ΔVDRAG) can be produced. In another example, ΔVDRAG can have a constant value. It should be appreciated that the above-described requirements of ΔVCROWN and ΔVDRAG can be changed to produce desirable user interface effects. 
     As can be seen from EQ. 1, the maintained velocity (VT) can continue to increase as long as ΔVCROWN is greater than ΔVDRAG. Additionally, VT can have non-zero values even when no ΔVCROWN input is being received, meaning that user interface objects can continue to change without the user rotating the crown. When this occurs, objects can stop changing based on the maintained velocity at the time the user stops rotating the crown and the ΔVDRAG component. 
     In some examples, when the crown is rotated in a direction corresponding to a rotation direction that is opposite the current user interface changes, the V(T−1) component can be reset to a value of zero, allowing the user to quickly change the direction of the object without having to provide a force sufficient to offset the VT. 
     At block  2210 , the system determines a speed of the focus selector. The speed of the focus selector may be determined based on crown velocity, as described above. 
     At block  2212 , the magnetic values of one or more of the selectable elements are modified based on the speed of the focus selector. In one example, the magnetic values of one or more selectable elements are inversely related to the speed of the focus selector. For example, when the focus selector has a speed above a first threshold, the magnetic values of the selectable elements are reduced by a factor of 10 from their original values. When the focus selector has a speed below the first threshold and above a second threshold, the magnetic values of the selectable elements are reduced by a factor of 5 from their original values. When the focus selector further slows down and has a speed below the second threshold, the magnetic values of the selectable elements are returned to their original values. 
     In addition, the speed of the focus selector is changed because of the physics-based magnetic interaction of the focus selector with the selection element based at least on the magnetic value associated with the selection element. For example, the physics-based magnetic attraction of the selection element may cause the speed of the focus selector to increase as the focus selector moves towards the selection element. Similarly, the physics-based magnetic attraction of the selection element may cause the speed of the focus selector to decrease as the focus selector moves away from the selection element. 
     Similarly, the magnetic interaction of the focus selector with other selectable elements may cause a change in the speed of the focus selector. For example, the speed of the focus selector may change as it approaches and passes an element that remains unselected. The change in the speed of the focus selector resulting from this interaction with the unselected element is based at least in part on the magnetic value of the unselected element. 
     In some examples, the magnetic values associated with the selectable elements are virtual magnetic strengths based on a virtual pull force. 
     In some examples, to add additional realism and provide further ease of usability to the user interface, the system may employ a physics-based model of friction to reduce the speed of the focus selector while it is in motion. For example, the speed of the focus selector can be continuously (or repeatedly) decreased based on a friction coefficient value. This physics-based friction model may simulate kinetic friction, drag friction, or the like. 
     In some examples, the device receives an additional input through the rotation of the crown before the focus selector reaches a steady state. An object is in a steady state when the object is not being translated, rotated, or scaled. In this example, the system determines a second change in the crown distance value. The system also determines a second direction, which is based on the direction of rotation of the physical crown of the wearable electronic device. In response to determining the second change in the crown distance value, the system increases or decreases the speed of the focus selector by applying an additional force to the focus selector. The change in the rate of the movement of the focus selector is based on the second change in the crown distance value and the second direction. 
     In some examples, once the focus selector aligns with the selection element and is in a steady state, the system determines that the selection element has been selected. 
       FIGS.  23 - 30    illustrate an exemplary user interface  2300  displaying multiple user interface objects in the form of selectable elements  2302 ,  2304 ,  2306 ,  2308  and a focus selector  2310 . A user can select a selection element from among the multiple selectable elements by using a physical crown of a wearable electronic device to move the focus selector  2310  to align with desired selection element. In some examples, additional input, such as tapping, pressing the crown or another button after the alignment may be required for the user to select the selection element. 
     Crown  558  of device  550  is a user rotatable user interface input (e.g., a rotatable input mechanism). The crown  558  can be turned in two distinct directions: clockwise and counterclockwise.  FIGS.  24 - 29    include rotation direction arrows illustrating the direction of crown rotation and movement direction arrows illustrating the direction of movement of one or more user interface objects, where applicable. The rotation direction arrows and movement direction arrows are typically not part of the displayed user interface, but are provided to aid in the interpretation of the figures. In this example, a counterclockwise direction rotation of the crown  558  is illustrated by a rotation direction arrow pointing in the down direction. The characteristics of the rotation direction arrow are not indicative of the distance, speed, or acceleration with which crown  558  is rotated by a user. Instead, the rotation direction arrow is indicative of the direction of rotation of crown  558  by the user. 
       FIGS.  23 - 30    illustrate an exemplary physics-based model that can be used to control a user&#39;s interactions with user interface objects in conjunction with a physical crown user input device. In this example, elements  2302 ,  2304 ,  2306 ,  2308  are stationary and focus selector  2310  is movable via user input received from crown  558 . Counterclockwise movement of the crown  558  is associated with a force on the focus selector  2310  in the down movement direction. 
     As described above, using a magnetic relationship between elements  2302 ,  2304 ,  2306 ,  2308  and focus selector  2310 , physics-based modeling can be used to simulate magnetic attraction between elements  1302 ,  1304 ,  1306 ,  1308  and focus selector  1310 . In addition, the movement of focus selector  2310  can be further controlled using a physics-based spring model. 
     Physics-based modeling of a spring is achieved, for example, by modeling a spring attached to elements  2302  and  2308 . As the focus selector  2310  moves beyond the limits of the plurality of selectable elements, a spring engages the focus selector  2310 , causing the focus selector to “rubberband.” For example, virtual springs  2312 ,  2314  may be modeled using Hook&#39;s law. Hook&#39;s law states that the force needed to extend or compress a spring by a distance is proportional to that distance. Phrased differently, F=kx, where F=force, k=spring coefficient, and x=distance. Springs  2312 ,  2314  are typically not part of the displayed user interface, but are provided to aid in the interpretation of the figures. 
     At  FIG.  23   , focus selector  2310  is aligned with element  2308 , indicating selection of element  2308 . At  FIG.  24   , device  550  determines a change in the position of crown  558  in the counterclockwise direction, as indicated by rotation direction arrow  2330 . In response to determining the change in the position of the crown  558 , the device increases the speed of focus selector  2310 , moving the focus selector  2310  in the down direction, as indicated by movement direction arrow  2320 . In one example, the focus selector may be associated with a mass or may have a calculated inertia. 
     Because element  2308  is modeled as a magnetic element and focus selector  2310  is modeled as a ferromagnetic material, there is a magnetic attraction between the two user interface objects. 
     At  FIGS.  24 - 26   , focus selector  2310  extends beyond the range of the selectable elements. As a result, spring  2314  engages the focus selector  2310 , causing focus selector  2310  to “rubberband” back, as illustrated in  FIGS.  27 - 30   . The spring coefficient of spring  2310  may be varied to produce results with different characteristics. 
     At  FIG.  30   , focus selector  2310  comes to rest while aligned with element  2308 . The system interprets this alignment as a selection of element  2308 , which is achieved by the user manipulating focus selector  2310  through the use of crown  558 . In some examples, additional input, such as tapping, pressing the crown or another button after the alignment may be required for the user to select element  2308 . 
     While element  2308  is selected, the user can activate element  2308  by one or more of many techniques. For example, the user may press on a touch-sensitive display, press on the touch-sensitive display with force above a predetermined threshold, press a button, or simply allow element  2308  to remain selected for a predetermined amount of time. In another example, aligning an element and a focus selector can be interpreted as both a selection and an activation of the element. 
     In this example, movement of the focus selector is constrained along a predefined vertical path. In other examples, movement of the focus selector may be constrained along a different predefined path, or may not be constrained to a predefined path. In this example, alignment in only one axis (the vertical axis) is used to indicate selection of an element. In some examples, alignment in two, three, or more axes may be required between an element and a focus selector to indicate a selection. 
       FIG.  31    is a flow diagram illustrating a process  3100  for selecting an element in a graphical user interface using a physical crown as an input device. Process  3100  is performed at a wearable electronic device (e.g., device  550  in  FIG.  1   ) having a physical crown. In some examples, the electronic device also includes a touch-sensitive display. The process provides an efficient technique for selecting an element from among multiple elements in a graphical user interface. 
     At block  3102 , the device causes a display of a plurality of selectable elements on a touch-sensitive display of a wearable electronic device. The device also causes a display of a focus selector. The device uses a physics-based model to simulate magnetic attraction between the selectable elements and the focus selector. Each selectable element of the plurality of selectable elements is associated with a corresponding magnetic value. The magnetic value can be the strength of an element&#39;s magnet attraction in terms of its pull force, and each element can have a different magnetic value. 
     At block  3104 , the device receives crown position information. The position information may be received as a series of pulse signals, real values, integer values, and the like. 
     At block  3106 , the device determines whether a change has occurred in a crown distance value. The crown distance value is based on an angular displacement of the physical crown of the wearable electronic device. A change in the crown distance value is indicative of a user providing input to the wearable electronic device by, for example, turning the physical crown. If the device determines that a change in the crown distance value has not occurred, the system returns to block  3104  and continues receiving crown position information. If the device determines that a change in the crown distance value has occurred, the system continues to block  3108 , though the system may continue to receive crown position information. 
     The device also determines a direction based on a direction of rotation of the physical crown of the wearable electronic device. For example, an up direction can be determined based on a clockwise rotation of the physical crown. Similarly, a down direction can be determined based on a counterclockwise rotation of the physical crown. In other examples, a down direction can be determined based on a clockwise rotation of the physical crown and an up direction can be determined based on a counterclockwise rotation of the physical crown. 
     At block  3108 , in response to determining the change in the crown distance value, the device causes a movement of the focus selector. This movement changes the focus of the plurality of selectable elements. At least initially, the movement of the focus selector is in the determined direction. The movement of the focus selector may be animated. The movement has a rate of movement (speed). Additionally, the magnetic values of one or more of the selectable elements may be modified based on the speed of the focus selector. 
     At block  3110 , the system determines whether the focus selector has extended beyond a predetermined limit. If the system determines that the focus selector has not extended beyond a predetermined limit, the system returns to block  3104 . If the system determines that the focus selector has extended beyond a predetermined limit, the system engages a virtual spring at block  3112 . The virtual spring causes the focus selector to slow down and rubberband back to within the predetermined limit. This mechanism will prevent a user from extending a focus selector too far beyond the scope of the selectable elements. At block  3104 , the system continues to receive crown position information. 
     In some examples, to add additional realism and provide further ease of usability to the user interface, the system may employ a physics-based model of friction to reduce the speed of the focus selector while it is in motion. For example, the speed of the focus selector can be continuously (or repeatedly) decreased based on a friction coefficient value. This physics-based friction model may simulate kinetic friction, drag friction, or the like. 
     In some examples, the device receives an additional input through the rotation of the crown before the focus selector reaches a steady state. An object is in a steady state when the object is not being translated, rotated, or scaled. In this example, the system determines a second change in the crown distance value. The system also determines a second direction, which is based on the direction of rotation of the physical crown of the wearable electronic device. In response to determining the second change in the crown distance value, the system increases or decreases the speed of the focus selector by applying an additional force to the focus selector. The change in the rate of the movement of the focus selector is based on the second change in the crown distance value and the second direction. 
     In some examples, once the focus selector aligns with the selection element and is in a steady state, the system determines that the selection element has been selected. In other examples, additional input, such as tapping, pressing the crown or another button after the alignment may be required for the user to select the selection element that aligns with the focus selector and is in a steady state. 
       FIGS.  32 - 38    illustrate an exemplary user interface  3200  displaying multiple user interface objects in the form of selectable elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  and focus area  3220 . A user can select a selection element from among the multiple selectable elements by using a physical crown of a wearable electronic device to scroll the selectable elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  to align the desired selection element with focus area  3220 . Focus area  3220  is typically not part of the displayed user interface, but is provided to aid in the interpretation of the figures. In some examples, additional input, such as tapping, pressing the crown or another button after the alignment may be required for the user to select the selection element. 
     Crown  558  of device  550  is a user rotatable user interface input (e.g., a rotatable input mechanism). The crown  558  can be turned in two distinct directions: clockwise and counterclockwise.  FIGS.  32 - 38    include rotation direction arrows illustrating the direction of crown rotation and movement direction arrows illustrating the direction of movement of one or more user interface objects, where applicable. The rotation direction arrows and movement direction arrows are typically not part of the displayed user interface, but are provided to aid in the interpretation of the figures. In this example, a clockwise direction rotation of the crown  558  is illustrated by a rotation direction arrow pointing in the up direction. Similarly, a counterclockwise direction rotation of the crown  558  is illustrated by a rotation direction arrow pointing in the down direction. The characteristics of the rotation direction arrow are not indicative of the distance, speed, or acceleration with which the crown  558  is rotated by a user. Instead, the rotation direction arrow is indicative of the direction of rotation of crown  558  by the user. 
       FIGS.  32 - 38    illustrate an exemplary scrollable list of elements using a physics-based model that can be used to control a user&#39;s interactions with user interface objects in conjunction with a physical crown user input device. In this example, elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  are scrollable via user input received from crown  558  and the focus area  3220  is stationary. Clockwise movement of crown  558  is associated with a force on elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  in the up movement direction and counterclockwise movement of crown  558  is associated with a force on elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  in the down movement direction. In this example, elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  form a scrollable list of elements. 
     To facilitate a user&#39;s ability to control the movement of the scrollable list of elements, a “magnetic” relationship is associated between each user selectable element and the focus area  3220 . In this example, the value of the magnetic relationship (also referred to as a magnetic value) between elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  and focus area  3220  is uniform. In other examples, the magnetic value of elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  can vary. 
     Using the magnetic relationship between elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  and focus area  3220 , physics-based modeling can be used to simulate magnetic attraction between elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  and focus area  3220 . As will be described in further detail below, user interface  3200  causes an attraction between elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  and focus area  3220 . As a result, when user input is not received, the multiple elements scroll to ultimately reach a steady state where one element is aligned with focus area  3220 . An object is in a steady state when the object is not being translated, rotated, or scaled. The alignment of an element with focus area  3220  is indicative of the selection of that element. This physics-based magnetic modeling results in the user interface exhibiting virtual detents. 
     In this example, physics-based modeling is achieved, for example, by modeling each element  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  as an object made from a magnetized material that creates its own persistent magnetic field and modeling focus area  3220  as a material that is attracted to a magnet, such as ferromagnetic materials including iron, cobalt, and nickel. In another example, the physics-based modeling can be achieved by modeling each element  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  as an object made from a material that is attracted to a magnet and modeling focus area  3220  as a material that creates its own persistent magnetic field. In another example, the physics-based modeling can be achieved by modeling each element  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  as an object that creates its own persistent magnetic field and modeling focus area  3220  as a material that also creates its own persistent magnetic field, such as two magnets that attract. Each of these physics-based models can be adapted to include magnetic fields that vary, rather than remain persistent, based on certain factors, such as the distance between the element and focus area  3220 , the speed of the elements, the acceleration of the elements, or based on a combination of two or more factors. For example, the varying magnetic field may be simulated through the use of an electromagnet, which can be turned on and off and can have a varying strength. 
     In one example, the magnetic strengths of elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  vary based on the speed of the scrollable list of elements. As the speed of the scrollable list of elements increases, the magnetic strength of elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  are reduced. As the speed of the scrollable list of elements increases, the magnetic strength of elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  is increased. As a result, when the scrollable list of elements is moving quickly, the elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  play a reduced role in changing the speed of the focus area as compared to when the scrollable list of elements is moving slowly. 
     At  FIG.  32   , element  3204  is aligned with focus area  3220 , indicating selection of element  3204 . At  FIG.  33   , device  550  determines a change in the position of crown  558  in the clockwise direction, as indicated by rotation direction arrow  3230 . In response to determining the change in the position of the crown  558 , the device increases the speed of the scrollable list of elements, moving the scrollable list of elements in the up direction, as indicated by movement direction arrow  3240 . In one example, the scrollable list of elements may be associated with a mass or may have a calculated inertia. 
     Because element  3204  is modeled as a magnetic element and focus area  3220  is modeled as a ferromagnetic material, there is a magnetic attraction between the two user interface objects. The physics-based model of user interface  3200  causes a resistance of the movement of element  3204  away from focus area  3220  using this magnetic attraction. An element&#39;s magnetic value (e.g., the strength of an element&#39;s magnet attraction) may be modeled, for example, in terms of its pull force (the elements ability to move other objects). The pull force exerted may be based on the pull force of either an electromagnet or a permanent magnet as described by the Maxwell equation. 
     At  FIGS.  33  and  34   , device  550  continues to determine a change in the position of crown  558  in the clockwise direction, as indicated by rotation direction arrow  3220 . In response to determining the changes in the position of the crown  558 , the device  550  adds additional speed to the scrollable list of elements in the up direction. At the same time, the magnetic attraction of elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  with focus area  3220  are acting on the scrollable list of elements. For example, at  FIG.  34   , at least elements  3204  and  3206  are applying a force to the scrollable list of elements in the down direction as a result of the magnetic physics-based modeling. This is because the elements  3204  and  3206  are attracted to the focus area  3220 . Elements  3208  and  3210  are applying a force to the scrollable list of elements in the up direction as a result of the magnetic physics-based modeling. This is because the elements  3208  and  3210  are also attracted to the focus area  3220 . In some examples, elements of the scrollable list of elements that are not displayed also apply a force to the scrollable list of elements. 
     The distance between the elements and focus area  3220  also play a role in the amount of force the elements apply to the scrollable list of elements. Generally, as the distance between the element and the focus area  3220  increases, the intensity of the force between the element and the focus area  3220  decreases. The rate of change in the intensity of the force can be modeled in many ways. For example, the inverse square law may apply the intensity of the force as a function of the distance. More specifically, I=1/d2, where I is the intensity of the force and d is the distance. In other examples, the magnetic force can vary in direct inverse proportion to distance or can vary inversely with the third power of distance. 
     In some examples, the magnetic attraction between an element and a focus area only exists while the element is within a predetermined distance from focus area  3220 . This simplifies calculations because the magnetic force of elements with a distance from focus area  3220  that is greater than the predetermined distance are not considered in determining the forces applied to the scrollable list of elements. 
     In some examples, to add additional realism and provide further ease of usability to the user interface, the system may also employ a physics-based model of friction to reduce the speed of the scrollable list of elements while it is in motion. For example, the speed of the scrollable list of elements can be continuously (or repeatedly) decreased based on a friction coefficient value. This physics-based friction model may simulate kinetic friction, drag friction, or the like. 
     At  FIGS.  35 - 38   , device  550  determines that there is no change in the position of crown  558 . As a result of this determination, no additional speed is added to the existing speed of the scrollable list of elements. However, the magnetic forces of elements  3202 ,  3204 ,  3206 ,  3208 ,  3210 ,  3212  continue to be applied the scrollable list of elements. Similarly, the physics-based friction model continues to be applied to the scrollable list of elements. At  FIGS.  35 - 38   , element  3208  has the largest magnetic effect on the scrollable list of elements, as compared to the other elements of the scrollable list of elements because element  3208  is the closest to focus area  3220 . This physics-based magnetic modeling results in the user interface exhibiting virtual detents. 
     At  FIG.  36   , as element  3208  overshoots focus area  3220 , element  3208  applies a force on the scrollable list of elements in the down direction, further reducing the speed of the scrollable list of elements. At  FIG.  37   , the magnetic force applied by element  3208  on the scrollable list of elements in the down direction causes the scrollable list of elements to move down, aligning element  3208  with focus area  3220 . The scrollable list of elements comes to rest while element  3208  is aligned with focus area  3220 . The system interprets this alignment as a selection of element  3208 , which is achieved by the user manipulating the scrollable list of elements through the use of crown  558 . 
     While element  3208  is selected, the user can activate element  3208  by one or more of many techniques. For example, the user may press on touch-sensitive display  556 , press on the touch-sensitive display with force above a predetermined threshold, press button  562 , or simply allow element  3208  to remain selected for a predetermined amount of time. In another example, aligning an element and a focus area can be interpreted as both a selection and an activation of the element. In some examples, additional input, such as tapping, pressing the crown or another button after the alignment may be required for the user to select the element. 
     User interface  3200  may be used, for example, for text entry on a device with a reduced-size display. Each element of the scrollable list of elements can correspond to a letter (such as a letter selected from A-Z), a word, a phrase, or a numeral (such as numeral selected from 0-9). A user can scroll through the alphanumeric elements, selecting and activating the desired elements sequentially to form a word, number, sentence, or the like. In examples where elements have various intensities of magnetic strength, the magnetic strength of an element associated with a letter of the alphabet may be based on the frequency of that letter&#39;s use. As a result, certain letters could be more magnetic than other letters, and therefore easier to select. 
     In this example, movement of the scrollable list of elements is constrained along a predefined vertical path. In other examples, movement of the scrollable list of elements may be constrained along a different predefined path, or may not be constrained to a predefined path. In this example, alignment in only one axis (the vertical axis) is used to indicate selection of an element. In some examples, alignment in two, three, or more axes may be required between an element and a focus area to indicate a selection. 
       FIG.  39    is a flow diagram illustrating a process  3900  for selecting an element in a graphical user interface using a physical crown as an input device. Process  3900  is performed at a wearable electronic device (e.g., device  550  in  FIG.  1   ) having a physical crown. In some examples, the electronic device also includes a touch-sensitive display. The process provides an efficient technique for selecting an element from among multiple elements in a graphical user interface. 
     At block  3902 , the device causes a display of a plurality of selectable elements on a touch-sensitive display of a wearable electronic device. The device also registers a focus area. The focus area may be, for example, an area, a line, or a point. The device uses a physics-based model to simulate magnetic attraction between the selectable elements and the focus area. Each selectable element of the plurality of selectable elements is associated with a corresponding magnetic value. The magnetic value can be the strength of an element&#39;s magnet attraction in terms of its pull force, and each element can have a different magnetic value. 
     At block  3904 , the device receives crown position information. The position information may be received as a series of pulse signals, real values, integer values, and the like. 
     At block  3906 , the device determines whether a change has occurred in a crown distance value. The crown distance value is based on an angular displacement of the physical crown of the wearable electronic device. A change in the crown distance value is indicative of a user providing input to the wearable electronic device by, for example, turning the physical crown. If the device determines that a change in the crown distance value has not occurred, the system returns to block  3904  and continues receiving crown position information. If the device determines that a change in the crown distance value has occurred, the system continues to block  3908 , though the system may continue to receive crown position information. 
     The device also determines a direction based on a direction of rotation of the physical crown of the wearable electronic device. For example, an up direction can be determined based on a clockwise rotation of the physical crown. Similarly, a down direction can be determined based on a counterclockwise rotation of the physical crown. In other examples, a down direction can be determined based on a clockwise rotation of the physical crown and an up direction can be determined based on a counterclockwise rotation of the physical crown. 
     At block  3908 , in response to determining the change in the crown distance value, the devices causes a movement of the plurality of selectable elements. The direction of the movement is such that a selection element of the plurality of selectable elements gets closer to the focus area than it was before the movement. This movement changes the focus of the plurality of selectable elements. At least initially, the movement of the plurality of selectable elements is in the determined direction. The movement of the plurality of selectable elements may be animated. The movement of the plurality of selectable elements has a rate of movement (speed). 
     At block  3910 , the magnetic values of one or more of the selectable elements are modified based on the speed of the plurality of selectable elements. In one example, the magnetic values of one or more selectable elements are inversely related to the speed of the plurality of selectable elements. For example, when the plurality of selectable elements has a speed above a first threshold, the magnetic values of the selectable elements are reduced by a first factor (e.g. 10) from their original values. When the plurality of selectable elements has a speed below the first threshold and above a second threshold, the magnetic values of the selectable elements are reduced by a second factor (e.g. 5) from their original values. When the plurality of selectable elements further slows down and has a speed below the second threshold, the magnetic values of the selectable elements are returned to their original values. The first factor is larger than the second factor. 
     In addition, the speed of the plurality of selectable elements is changed because of the physics-based magnetic interaction of the plurality of selectable elements with the focus area based at least on the magnetic value associated with the selection element. For example, the physics-based magnetic attraction of the selection element to the focus area may cause the speed of the plurality of selectable elements to increase as the selection element moves towards the focus area. Similarly, the physics-based magnetic attraction of the selection element to the focus area may cause the speed of the plurality of selectable elements to decrease as the selection element moves away from the focus area. Similarly, the magnetic interaction of the focus area with other selectable elements of the plurality of selectable elements may cause a change in the speed of the plurality of selectable elements. 
     In some examples, the magnetic values associated with the selectable elements are virtual magnetic strengths based on a virtual pull force between the selectable element and the focus area. 
     In some examples, to add additional realism and provide further ease of usability to the user interface, the system may employ a physics-based model of friction to reduce the speed of the plurality of selectable elements while it is in motion. For example, the speed of the plurality of selectable elements can be continuously (or repeatedly) decreased based on a friction coefficient value. This physics-based friction model may simulate kinetic friction, drag friction, or the like. 
     In some examples, the device receives an additional input through the rotation of the crown before the plurality of selectable elements reach a steady state. An object is in a steady state when the object is not being translated, rotated, or scaled. In this example, the system determines a second change in the crown distance value. The system also determines a second direction, which is based on the direction of rotation of the physical crown of the wearable electronic device. In response to determining the second change in the crown distance value, the system increases or decreases the speed of the plurality of selectable elements by applying an additional force to the plurality of selectable elements. The change in the rate of the movement of the plurality of selectable elements is based on the second change in the crown distance value and the second direction. 
     In some examples, once the selection element aligns with the focus area and the plurality of selectable elements are in a steady state, the system determines that the selection element has been selected. 
       FIGS.  40 - 45    illustrate an exemplary user interface  4000  displaying multiple user interface objects in the form of selectable elements  4002 ,  4004  and a focus area  4006 . A scrollable list of elements includes selectable elements  4002 ,  4004 . A user can select a selection element from among the multiple selectable elements by using a physical crown of a wearable electronic device to move the scrollable list of elements to align a desired selection element with the focus area  4006 . 
     Crown  558  of device  550  is a user rotatable user interface input. Crown  558  can be turned in two distinct directions: clockwise and counterclockwise.  FIGS.  40 - 45    include rotation direction arrows illustrating the direction of crown rotation and movement direction arrows illustrating the direction of movement of the scrollable list of elements, where applicable. The rotation direction arrows and movement direction arrows are typically not part of the displayed user interface, but are provided to aid in the interpretation of the figures. In this example, a counterclockwise direction rotation of crown  558  is illustrated by a rotation direction arrow pointing in the down direction. The characteristics of the rotation direction arrow are not indicative of the distance, speed, or acceleration with which crown  558  is rotated by a user. Instead, the rotation direction arrow is indicative of the direction of rotation of crown  558  by the user. 
       FIGS.  40 - 45    illustrate an exemplary physics-based model that can be used to control a user&#39;s interactions with user interface objects in conjunction with a physical crown user input device. In this example, focus area  4006  is stationary and elements  4002 ,  4004  are movable via user input received from crown  558 . Counterclockwise movement of crown  558  is associated with a force on the scrollable list of elements in the down movement direction. 
     As described above, using a magnetic relationship between focus area  4006  and elements  4002 ,  4004 , physics-based modeling can be used to simulate magnetic attraction between elements focus area  4006  and elements  4002 ,  4004 . In addition, the movement of the scrollable list of elements can be further controlled using a physics-based spring model. 
     Physics-based modeling of a spring is achieved, for example, by modeling a spring attached to one or more ends of the scrollable list of elements. As the scrollable list of elements moves beyond a predetermined limit, a spring engages the scrollable list of elements, causing the scrollable list of elements to “rubberband.” For example, virtual spring  4008  in  FIGS.  41 - 44    may be modeled using Hook&#39;s law. Hook&#39;s law states that the force needed to extend or compress a spring by a distance is proportional to that distance. Phrased differently, F=kx, where F=force, k=spring coefficient, and x=distance. Spring  4008  is typically not part of the displayed user interface, but is provided to aid in the interpretation of the figures. 
     At  FIG.  40   , element  4002  is aligned with focus area  4006 , indicating selection of element  4002 . At  FIG.  41   , device  550  determines a change in the position of crown  558  in the counterclockwise direction, as indicated by rotation direction arrow  4010 . In response to determining the change in the position of the crown  558 , the device increases the speed of the scrollable list of elements, moving the elements  4002 ,  4004  in the down direction, as indicated by movement direction arrow  4012 . In one example, the scrollable list of elements may be associated with a mass or may have a calculated inertia. 
     Because element  4002  is modeled as a magnetic element and focus area  4006  is modeled as a ferromagnetic material, there is a magnetic attraction between the two user interface objects. 
     At  FIGS.  41 - 42   , the scrollable list of elements extends beyond the predetermined limit. As a result, spring  4008  engages the scrollable list of elements, causing the scrollable list of elements to “rubberband” back, as illustrated in  FIGS.  43 - 45   . The spring coefficient of spring  4008  may be varied to produce results with different characteristics. 
     At  FIG.  45   , element  4002  comes to rest while aligned with focus area  4006 . The system interprets this alignment as a selection of element  4006 , which is achieved by the user manipulating the scrollable list of elements through the use of crown  558 . In some examples, additional input, such as tapping, pressing the crown or another button after the alignment may be required for the user to select element  4006 . 
     While element  4002  is selected, the user can activate element  4002  by one or more of many techniques. For example, the user may press on a touch-sensitive display, press a button, or simply allow element  4002  to remain selected for a predetermined amount of time. In another example, aligning an element and a focus area can be interpreted as both a selection and an activation of the element. 
     In this example, movement of the scrollable list of elements is constrained along a predefined vertical path. In other examples, movement of the scrollable list of elements may be constrained along a different predefined path, or may not be constrained to a predefined path. In this example, alignment in only one axis (the vertical axis) is used to indicate selection of an element. In some examples, alignment in two, three, or more axes may be required between an element and a focus area to indicate a selection. 
       FIG.  46    is a flow diagram illustrating a process  4600  for selecting an element in a graphical user interface using a physical crown as an input device. Process  4600  is performed at a wearable electronic device (e.g., device  550  in  FIG.  1   ) having a physical crown. In some examples, the electronic device also includes a touch-sensitive display. The process provides an efficient technique for selecting an element from among multiple elements in a graphical user interface. 
     At block  4602 , the device causes a display of a plurality of selectable elements on a touch-sensitive display of a wearable electronic device. The device also registers a focus area. The device uses a physics-based model to simulate magnetic attraction between the selectable elements and the focus area. Each selectable element of the plurality of selectable elements is associated with a corresponding magnetic value. The magnetic value can be the strength of an element&#39;s magnet attraction in terms of its pull force, and each element can have a different magnetic value. 
     At block  4604 , the device receives crown position information. The position information may be received as a series of pulse signals, real values, integer values, and the like. 
     At block  4606 , the device determines whether a change has occurred in a crown distance value. The crown distance value is based on an angular displacement of the physical crown of the wearable electronic device. A change in the crown distance value is indicative of a user providing input to the wearable electronic device by, for example, turning the physical crown. If the device determines that a change in the crown distance value has not occurred, the system returns to block  4604  and continues receiving crown position information. If the device determines that a change in the crown distance value has occurred, the system continues to block  4608 , though the system may continue to receive crown position information. 
     The device also determines a direction based on a direction of rotation of the physical crown of the wearable electronic device. For example, an up direction can be determined based on a clockwise rotation of the physical crown. Similarly, a down direction can be determined based on a counterclockwise rotation of the physical crown. In other examples, a down direction can be determined based on a clockwise rotation of the physical crown and an up direction can be determined based on a counterclockwise rotation of the physical crown. 
     At block  4608 , in response to determining the change in the crown distance value, the device causes a movement of the plurality of selectable elements. This movement changes the focus of the plurality of selectable elements. At least initially, the movement of the plurality of selectable elements is in the determined direction. The movement of the plurality of selectable elements may be animated. The movement has a rate of movement (speed). Additionally, the magnetic values of one or more of the selectable elements may be modified based on the speed of the plurality of selectable elements. 
     At block  4610 , the system determines whether the plurality of selectable elements has extended beyond a predetermined limit. If the system determines that the plurality of selectable elements has not extended beyond a predetermined limit, the system returns to block  4604 . If the system determines that the plurality of selectable elements has extended beyond a predetermined limit, the system engages a virtual spring at block  4612 . The virtual spring causes the plurality of selectable elements to slow down and rubberband back to within the predetermined limit. This mechanism will prevent a user from extending the plurality of selectable elements too far beyond the predetermined limit. At block  4604 , the system continues to receive crown position information. 
     In some examples, to add additional realism and provide further ease of usability to the user interface, the system may employ a physics-based model of friction to reduce the speed of the plurality of selectable elements while it is in motion. For example, the speed of the plurality of selectable elements can be continuously (or repeatedly) decreased based on a friction coefficient value. This physics-based friction model may simulate kinetic friction, drag friction, or the like. 
     In some examples, the device receives an additional input through the rotation of the crown before the plurality of selectable elements reaches a steady state. An object is in a steady state when the object is not being translated, rotated, or scaled. In this example, the system determines a second change in the crown distance value. The system also determines a second direction, which is based on the direction of rotation of the physical crown of the wearable electronic device. In response to determining the second change in the crown distance value, the system increases or decreases the speed of the plurality of selectable elements by applying an additional force to the plurality of selectable elements. The change in the rate of the movement of the plurality of selectable elements is based on the second change in the crown distance value and the second direction. 
     In some examples, once the selection element of the plurality of selectable elements aligns with the focus area and the plurality of selectable elements is in a steady state, the system determines that the selection element has been selected. In some examples, additional input, such as tapping, pressing the crown or another button after the alignment may be required for the user to select the selection element. 
     In some examples, device  550  can provide haptic feedback based on the content displayed on the display  556 . When a user interface object is displayed on the display  556 , the device can modify the appearance of the object based on a change in a crown distance value received at the device  550  based on a rotation of crown  558 . When a criterion is satisfied, a tactile output is output at the device  550 . 
     In one example, the object is a scrollable list of elements, such as is described above. The criterion is satisfied when a beginning or an end of the scrollable list is reached. In another example, the object is a zoomable visual element. The criterion is satisfied when a maximum or minimum zoom level of the zoomable visual element is reached. In another example, the object is a scrollable list of selectable elements. The criterion is satisfied each time a selectable element of the scrollable list occupies a selection area. 
     One or more of the functions relating to a user interface can be performed by a system similar or identical to system  4700  shown in  FIG.  47   . System  4700  can include instructions stored in a non-transitory computer readable storage medium, such as memory  4704  or storage device  4702 , and executed by processor  4706 . The instructions can also be stored and/or transported within any non-transitory computer readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “non-transitory computer readable storage medium” can be any medium that can contain or store the program for use by or in connection with the instruction execution system, apparatus, or device. The non-transitory computer readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus or device, a portable computer diskette (magnetic), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM) (magnetic), a portable optical disc such a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW, or flash memory such as compact flash cards, secured digital cards, USB memory devices, memory sticks, and the like. 
     The instructions can also be propagated within any transport medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “transport medium” can be any medium that can communicate, propagate or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The transport medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic or infrared wired or wireless propagation medium. 
     In some examples, system  4700  can be included within device  550 . In these examples, processor  4706  can be the same or a different process than processor  570 . Processor  4706  can be configured to receive the output from encoder  572 , buttons  560 ,  562 , and  564 , and from touch-sensitive display  556 . Processor  4706  can process these inputs as described above with respect to the processes described and illustrated. It is to be understood that the system is not limited to the components and configuration of  FIG.  47   , but can include other or additional components in multiple configurations according to various examples. 
     The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the various described embodiments to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the various described embodiments and their practical applications, to thereby enable others skilled in the art to best utilize the various described embodiments with various modifications as are suited to the particular use contemplated.