Patent Publication Number: US-2011074694-A1

Title: Device and Method for Jitter Reduction on Touch-Sensitive Surfaces and Displays

Description:
TECHNICAL FIELD 
     The disclosed embodiments relate generally to electronic devices with touch-sensitive surfaces, and more particularly, to electronic devices and methods for reducing jitter associated with user contacts on touch-sensitive surfaces. 
     BACKGROUND 
     The use of touch-sensitive surfaces as input devices for computers and other electronic computing devices has increased significantly in recent years. Exemplary touch-sensitive surfaces include touch pads and touch screen displays. Such surfaces are widely used to manipulate user interface objects on a display. 
     However, jitter associated with user contacts on touch-sensitive surfaces prevent a user from easily placing and/or adjusting moveable user interface objects. Jitter occurs when a user who is manipulating a moveable user interface object pauses a finger contact on a touch-sensitive surface, or lifts a finger contact off of the touch-sensitive surface. As the user pauses or lifts off the finger contact, an unintentional finger contact motion may be registered on the touch-sensitive surface. This motion inadvertently moves the moveable user interface object to a location slightly off from the desired location. In fact, in many touch-sensitive surface input-based systems, exact placement or adjustment of moveable user interface objects can be impossible for users with limited dexterity, and simply frustrating for more adept users. 
     Accordingly, a method of reducing jitter when a user is placing and/or adjusting moveable user interface objects is needed so that users avoid the tedious and significant cognitive burden associated with accurately placing moveable 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. 
     SUMMARY 
     The above deficiencies and other problems associated with user interfaces for computing devices with touch-sensitive surfaces 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 has a touch-sensitive display (also known as a “touch screen” or “touch screen display”). 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 finger contacts and gestures on the touch-sensitive surface. In some embodiments, the functions may include image editing, drawing, presenting, word processing, website creating, disk authoring, spreadsheet making, game playing, telephoning, video conferencing, e-mailing, instant messaging, workout support, digital photographing, digital videoing, web browsing, digital music playing, and/or digital video playing. 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 a multifunction device with a display and a touch-sensitive surface. The method includes: displaying a user interface that includes a moveable object at a first location on the display; detecting a finger contact on the touch-sensitive surface at a location on the touch-sensitive surface that corresponds to the first location of the moveable object on the display; creating an event log entry that corresponds to the finger contact in an event log comprising event log entries, wherein respective event log entries include contact location data and contact time data; detecting a first movement of the finger contact across the touch-sensitive surface; creating one or more event log entries that correspond to the first movement of the finger contact; and, in response to detecting the first movement of the finger contact: when the first movement is less than a first predefined distance threshold, maintaining display of the moveable object at the first location; and, when the first movement is greater than or equal to the first predefined distance threshold: delaying movement of the moveable object from the first location until a second movement of the finger contact after the first movement of the finger contact movement is detected, creating one or more event log entries that correspond to the second movement of the finger contact, and, after detecting the second movement of the finger contact on the touch-sensitive surface, moving the moveable object on the display in accordance with the movement of the finger contact on the touch-sensitive surface. 
     In accordance with some embodiments, a multifunction device includes a display, a touch-sensitive surface, one or more processors, memory, and one or more programs. The one or more programs are stored in the memory and configured to be executed by the one or more processors. The one or more programs include instructions for: displaying a user interface that includes a moveable object at a first location on the display; detecting a finger contact on the touch-sensitive surface at a location on the touch-sensitive surface that corresponds to the first location of the moveable object on the display; creating an event log entry that corresponds to the finger contact in an event log comprising event log entries, wherein respective event log entries include contact location data and contact time data; detecting a first movement of the finger contact across the touch-sensitive surface; creating one or more event log entries that correspond to the first movement of the finger contact; and, in response to detecting the first movement of the finger contact: when the first movement is less than a first predefined distance threshold, maintaining display of the moveable object at the first location; and, when the first movement is greater than the first predefined distance threshold: delaying movement of the moveable object from the first location until a second movement of the finger contact after the first movement of the finger contact movement is detected, creating one or more event log entries that correspond to the second movement of the finger contact, and, after detecting the second movement of the finger contact on the touch-sensitive surface, moving the moveable object on the display in accordance with the movement of the finger contact on the touch-sensitive surface. 
     In accordance with some embodiments, a computer readable storage medium has stored therein instructions which when executed by a multifunction device with a display and a touch-sensitive surface, cause the device to: display a user interface that includes a moveable object at a first location on the display; detect a finger contact on the touch-sensitive surface at a location on the touch-sensitive surface that corresponds to the first location of the moveable object on the display; create an event log entry that corresponds to the finger contact in an event log comprising event log entries, wherein respective event log entries include contact location data and contact time data; detect a first movement of the finger contact across the touch-sensitive surface; create one or more event log entries that correspond to the first movement of the finger contact; and, in response to detecting the first movement of the finger contact: when the first movement is less than a first predefined distance threshold, maintain display of the moveable object at the first location; and, when the first movement is greater than the first predefined distance threshold: delay movement of the moveable object from the first location until a second movement of the finger contact after the first movement of the finger contact movement is detected, create one or more event log entries that correspond to the second movement of the finger contact, and, after detecting the second movement of the finger contact on the touch-sensitive surface, move the moveable object on the display in accordance with the movement of the finger contact on the touch-sensitive surface. 
     In accordance with some embodiments, a multifunction device includes: a display; a touch-sensitive surface; means for displaying a user interface that includes a moveable object at a first location on the display; means for detecting a finger contact on the touch-sensitive surface at a location on the touch-sensitive surface that corresponds to the first location of the moveable object on the display; means for creating an event log entry that corresponds to the finger contact in an event log comprising event log entries, wherein respective event log entries include contact location data and contact time data; means for detecting a first movement of the finger contact across the touch-sensitive surface; means for creating one or more event log entries that correspond to the first movement of the finger contact; and, in response to detecting the first movement of the finger contact: when the first movement is less than a first predefined distance threshold, means for maintaining display of the moveable object at the first location; and, when the first movement is greater than the first predefined distance threshold: means for delaying movement of the moveable object from the first location until a second movement of the finger contact after the first movement of the finger contact movement is detected, means for creating one or more event log entries that correspond to the second movement of the finger contact, and, after detecting the second movement of the finger contact on the touch-sensitive surface, means for moving the moveable object on the display in accordance with the movement of the finger contact on the touch-sensitive surface. 
     In accordance with some embodiments, an information processing apparatus for use in a multifunction device with a display and a touch-sensitive surface includes: means for displaying a user interface that includes a moveable object at a first location on the display; means for detecting a finger contact on the touch-sensitive surface at a location on the touch-sensitive surface that corresponds to the first location of the moveable object on the display; means for creating an event log entry that corresponds to the finger contact in an event log comprising event log entries, wherein respective event log entries include contact location data and contact time data; means for detecting a first movement of the finger contact across the touch-sensitive surface; means for creating one or more event log entries that correspond to the first movement of the finger contact; and, in response to detecting the first movement of the finger contact: when the first movement is less than a first predefined distance threshold, means for maintaining display of the moveable object at the first location; and, when the first movement is greater than the first predefined distance threshold: means for delaying movement of the moveable object from the first location until a second movement of the finger contact after the first movement of the finger contact movement is detected, means for creating one or more event log entries that correspond to the second movement of the finger contact, and, after detecting the second movement of the finger contact on the touch-sensitive surface, means for moving the moveable object on the display in accordance with the movement of the finger contact on the touch-sensitive surface. 
     Thus, multifunction devices with displays and touch-sensitive surfaces are provided with faster, more efficient methods and interfaces for reducing jitter associated with user contacts on touch-sensitive surfaces, thereby increasing the effectiveness, efficiency, and user satisfaction with such devices. Such methods and interfaces may complement or replace conventional methods for reducing jitter associated with user contacts on touch-sensitive surfaces. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the aforementioned embodiments of the invention as well as additional embodiments thereof, 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. 
         FIGS. 1A and 1B  are block diagrams illustrating portable multifunction devices with touch-sensitive displays in accordance with some embodiments. 
         FIG. 2  illustrates a portable multifunction device having a touch screen in accordance with some embodiments. 
         FIG. 3A  is a block diagram of an exemplary multifunction device with a display and a touch-sensitive surface in accordance with some embodiments. 
         FIG. 3B  illustrates an exemplary block diagram of a contact motion module event handler and event log entry structure in accordance with some embodiments. 
         FIG. 3C  illustrates an exemplary state machine diagram for a contact event jitter reduction submodule in accordance with some embodiments. 
         FIGS. 4A and 4B  illustrate exemplary user interfaces for a menu of applications on a portable multifunction device in accordance with some embodiments. 
         FIG. 4C  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. 
         FIGS. 5A-5L  illustrate exemplary user interfaces for reducing jitter associated with user contacts on touch-sensitive surfaces in accordance with some embodiments. 
         FIGS. 6A-6C  are flow diagrams illustrating a method of reducing jitter associated with user contacts on touch-sensitive surfaces in accordance with some embodiments. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the embodiments. 
     It will also be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first contact could be termed a second contact, and, similarly, a second contact could be termed a first contact, without departing from the scope of the present invention. The first contact and the second contact are both contacts, but they are not the same contact. 
     The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the invention 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. 
     As used herein, 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 computing devices, user interfaces for such devices, and associated processes for using such devices are described. In some embodiments, the computing 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® and iPod Touch® devices from Apple, Inc. of Cupertino, Calif. Other portable devices such as laptops or tablet computers with touch-sensitive surfaces (e.g., touch screen displays and/or touch pads) may also be 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, a computing device that includes a display and a touch-sensitive surface is described. It should be understood, however, that the computing device may include one or more other physical user-interface devices, such as a physical keyboard, a mouse and/or a joystick. 
     The device supports 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 may be executed on the device may 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 may be 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 may support the variety of applications with user interfaces that are intuitive and transparent. 
     The user interfaces may include one or more soft keyboard embodiments. The soft keyboard embodiments may include standard (QWERTY) and/or non-standard configurations of symbols on the displayed icons of the keyboard, such as those described in U.S. patent application Ser. No. 11/459,606, “Keyboards For Portable Electronic Devices,” filed Jul. 24, 2006, and Ser. No. 11/459,615, “Touch Screen Keyboards For Portable Electronic Devices,” filed Jul. 24, 2006, the contents of which are hereby incorporated by reference in their entirety. The keyboard embodiments may include a reduced number of icons (or soft keys) relative to the number of keys in existing physical keyboards, such as that for a typewriter. This may make it easier for users to select one or more icons in the keyboard, and thus, one or more corresponding symbols. The keyboard embodiments may be adaptive. For example, displayed icons may be modified in accordance with user actions, such as selecting one or more icons and/or one or more corresponding symbols. One or more applications on the device may utilize common and/or different keyboard embodiments. Thus, the keyboard embodiment used may be tailored to at least some of the applications. In some embodiments, one or more keyboard embodiments may be tailored to a respective user. For example, one or more keyboard embodiments may be tailored to a respective user based on a word usage history (lexicography, slang, individual usage) of the respective user. Some of the keyboard embodiments may be adjusted to reduce a probability of a user error when selecting one or more icons, and thus one or more symbols, when using the soft keyboard embodiments. 
     Attention is now directed towards embodiments of portable devices with touch-sensitive displays.  FIGS. 1A and 1B  are block diagrams illustrating portable multifunction devices  100  with touch-sensitive displays  112  in accordance with some embodiments. The touch-sensitive display  112  is sometimes called a “touch screen” for convenience, and may also be known as or called a touch-sensitive display system. The device  100  may include a memory  102  (which may include one or more computer readable storage mediums), a memory controller  122 , one or more processing units (CPU&#39;s)  120 , a peripherals interface  118 , RF circuitry  108 , audio circuitry  110 , a speaker  111 , a microphone  113 , an input/output (I/O) subsystem  106 , other input or control devices  116 , and an external port  124 . The device  100  may include one or more optical sensors  164 . These components may communicate over one or more communication buses or signal lines  103 . 
     It should be appreciated that the device  100  is only one example of a portable multifunction device  100 , and that the device  100  may have more or fewer components than shown, may combine two or more components, or a may have a different configuration or arrangement of the components. The various components shown in  FIGS. 1A and 1B  may be 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 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. Access to memory  102  by other components of the device  100 , such as the CPU  120  and the peripherals interface  118 , may be controlled by the memory controller  122 . 
     The peripherals interface  118  couples the input and output peripherals of the device to the 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 the device  100  and to process data. 
     In some embodiments, the peripherals interface  118 , the CPU  120 , and the memory controller  122  may be implemented on a single chip, such as a chip  104 . In some other embodiments, they may be implemented on separate chips. 
     The RF (radio frequency) circuitry  108  receives and sends RF signals, also called electromagnetic signals. The RF circuitry  108  converts electrical signals to/from electromagnetic signals and communicates with communications networks and other communications devices via the electromagnetic signals. The RF circuitry  108  may include 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. The RF circuitry  108  may communicate 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 may use 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), wideband code division multiple access (W-CDMA), code division multiple access (CDMA), time division multiple access (TDMA), Bluetooth, 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 email (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. 
     The audio circuitry  110 , the speaker  111 , and the microphone  113  provide an audio interface between a user and the device  100 . The audio circuitry  110  receives audio data from the peripherals interface  118 , converts the audio data to an electrical signal, and transmits the electrical signal to the speaker  111 . The speaker  111  converts the electrical signal to human-audible sound waves. The audio circuitry  110  also receives electrical signals converted by the microphone  113  from sound waves. The audio circuitry  110  converts the electrical signal to audio data and transmits the audio data to the peripherals interface  118  for processing. Audio data may be retrieved from and/or transmitted to memory  102  and/or the RF circuitry  108  by the peripherals interface  118 . In some embodiments, the audio circuitry  110  also includes a headset jack (e.g.  212 ,  FIG. 2 ). The headset jack provides an interface between the 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). 
     The I/O subsystem  106  couples input/output peripherals on the device  100 , such as the touch screen  112  and other input/control devices  116 , to the peripherals interface  118 . The I/O subsystem  106  may include a display controller  156  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  may 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  may be 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 ) may include an up/down button for volume control of the speaker  111  and/or the microphone  113 . The one or more buttons may include a push button (e.g.,  206 ,  FIG. 2 ). A quick press of the push button may disengage a lock of the 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, which is hereby incorporated by reference in its entirety. A longer press of the push button (e.g.,  206 ) may turn power to the device  100  on or off. The user may be able to customize a functionality of one or more of the buttons. The touch screen  112  is used to implement virtual or soft buttons and one or more soft keyboards. 
     The touch-sensitive touch screen  112  provides an input interface and an output interface between the device and a user. The display controller  156  receives and/or sends electrical signals from/to the touch screen  112 . The 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. 
     A 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. The touch screen  112  and the 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 the 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 the touch screen. In an exemplary embodiment, a point of contact between a touch screen  112  and the user corresponds to a finger of the user. 
     The touch screen  112  may use LCD (liquid crystal display) technology, or LPD (light emitting polymer display) technology, although other display technologies may be used in other embodiments. The touch screen  112  and the 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 a 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 the 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, a touch screen  112  displays visual output from the portable device  100 , whereas touch sensitive touchpads do not provide visual output. 
     A touch-sensitive display in some embodiments of the 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. 
     The touch screen  112  may have a resolution in excess of 100 dpi. In an exemplary embodiment, the touch screen has a resolution of approximately 160 dpi. The user may make contact with the 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 are much 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, the 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 the touch screen  112  or an extension of the touch-sensitive surface formed by the touch screen. 
     In some embodiments, the device  100  may include a physical or virtual click wheel as an input control device  116 . A user may navigate among and interact with one or more graphical objects (e.g., icons) displayed in the touch screen  112  by rotating the click wheel or by moving a point of contact with the click wheel (e.g., where the amount of movement of the point of contact is measured by its angular displacement with respect to a center point of the click wheel). The click wheel may also be used to select one or more of the displayed icons. For example, the user may press down on at least a portion of the click wheel or an associated button. User commands and navigation commands provided by the user via the click wheel may be processed by an input controller  160  as well as one or more of the modules and/or sets of instructions in memory  102 . For a virtual click wheel, the click wheel and click wheel controller may be part of the touch screen  112  and the display controller  156 , respectively. For a virtual click wheel, the click wheel may be either an opaque or semitransparent object that appears and disappears on the touch screen display in response to user interaction with the device. In some embodiments, a virtual click wheel is displayed on the touch screen of a portable multifunction device and operated by user contact with the touch screen. 
     The device  100  also includes a power system  162  for powering the various components. The 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. 
     The device  100  may also include one or more optical sensors  164 .  FIGS. 1A and 1B  show an optical sensor coupled to an optical sensor controller  158  in I/O subsystem  106 . The optical sensor  164  may include charge-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) phototransistors. The 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 an imaging module  143  (also called a camera module), the optical sensor  164  may capture still images or video. In some embodiments, an optical sensor is located on the back of the device  100 , opposite the 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 the 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. 
     The device  100  may also include one or more proximity sensors  166 .  FIGS. 1A and 1B  show a proximity sensor  166  coupled to the peripherals interface  118 . Alternately, the proximity sensor  166  may be coupled to an input controller  160  in the I/O subsystem  106 . The 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 the 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). 
     The device  100  may also include one or more accelerometers  168 .  FIGS. 1A and 1B  show an accelerometer  168  coupled to the peripherals interface  118 . Alternately, the accelerometer  168  may be coupled to an input controller  160  in the I/O subsystem  106 . The 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. 
     In some embodiments, the software components stored in memory  102  may include an operating system  126 , a communication module (or set of instructions)  128 , a contact/motion module (or set of instructions)  130 , a graphics module (or set of instructions)  132 , a text input module (or set of instructions)  134 , a Global Positioning System (GPS) module (or set of instructions)  135 , and applications (or set of instructions)  136 . 
     The operating system  126  (e.g., Darwin, RTXC, LINUX, UNIX, OS X, 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. 
     The 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 the RF circuitry  108  and/or the external port  124 . The 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. 
     The contact/motion module  130  may detect contact with the touch screen  112  (in conjunction with the display controller  156 ) and other touch sensitive devices (e.g., a touchpad or physical click wheel). The 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 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). The 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, may include 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 may be applied to single contacts (e.g., one finger contacts) or to multiple simultaneous contacts (e.g., “multitouch”/multiple finger contacts). In some embodiments, the contact/motion module  130  and the display controller  156  detects contact on a touchpad. In some embodiments, the contact/motion module  130  and the controller  160  detects contact on a click wheel. 
     The contact/motion module  130  may detect a gesture input by a user. Different gestures on the touch-sensitive surface have different contact patterns. Thus, a gesture may be 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 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 event. 
     The graphics module  132  includes various known software components for rendering and displaying graphics on the touch screen  112  or other display, including components for changing the intensity 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, the graphics module  132  stores data representing graphics to be used. Each graphic may be assigned a corresponding code. The 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 . 
     The 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). 
     The 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). 
     The applications  136  may include the following modules (or sets of instructions), or a subset or superset thereof:
         a contacts module  137  (sometimes called an address book or contact list);   a telephone module  138 ;   a video conferencing module  139 ;   an e-mail client module  140 ;   an instant messaging (IM) module  141 ;   a workout support module  142 ;   a camera module  143  for still and/or video images;   an image management module  144 ;   a video player module  145 ;   a music player module  146 ;   a browser module  147 ;   a calendar module  148 ;   widget modules  149 , which may include 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 , the contacts module  137  may be used to manage an address book or contact list, 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 , the telephone module  138  may be used to enter a sequence of characters corresponding to a telephone number, access one or more telephone numbers in the 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 , contacts list  137 , and telephone module  138 , the videoconferencing module  139  may be used to initiate, conduct, and terminate a video conference between a user and one or more other participants. 
     In conjunction with RF circuitry  108 , touch screen  112 , display controller  156 , contact module  130 , graphics module  132 , and text input module  134 , the e-mail client module  140  may be used to create, send, receive, and manage e-mail. In conjunction with image management module  144 , the e-mail 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  may be used 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 , the workout support module  142  may be used 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 , the camera module  143  may be used 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 , the image management module  144  may be used 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 touch screen  112 , display controller  156 , contact module  130 , graphics module  132 , audio circuitry  110 , and speaker  111 , the video player module  145  may be used to display, present or otherwise play back videos (e.g., on the touch screen or on an external, connected display via external port  124 ). 
     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 , the music player module  146  allows 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. In some embodiments, the device  100  may include the functionality of an MP3 player, such as an iPod (trademark of Apple, Inc.). 
     In conjunction with RF circuitry  108 , touch screen  112 , display system controller  156 , contact module  130 , graphics module  132 , and text input module  134 , the browser module  147  may be used to browse the Internet, 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 module  140 , and browser module  147 , the calendar module  148  may be used to create, display, modify, and store calendars and data associated with calendars (e.g., calendar entries, to do lists, etc.). 
     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 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 , the search module  151  may be used 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 conjunction with touch screen  112 , display controller  156 , contact module  130 , graphics module  132 , and text input module  134 , the notes module  153  may be used to create and manage notes, to do lists, and the like. 
     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 , the 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 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 , the online video module  155  allows 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. 1B ). 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, the device  100  is a device where operation of a predefined set of functions on the device is performed exclusively through a touch screen  112  and/or a touchpad. By using a touch screen and/or a touchpad as the primary input/control device for operation of the device  100 , the number of physical input/control devices (such as push buttons, dials, and the like) on the device  100  may be reduced. 
     The predefined set of functions that may be performed exclusively through a touch screen and/or a touchpad include navigation between user interfaces. In some embodiments, the touchpad, when touched by the user, navigates the device  100  to a main, home, or root menu from any user interface that may be displayed on the device  100 . In such embodiments, the touchpad may be referred to as a “menu button.” In some other embodiments, the menu button may be a physical push button or other physical input/control device instead of a touchpad. 
       FIG. 2  illustrates a portable multifunction device  100  having a touch screen  112  in accordance with some embodiments. The touch screen may display one or more graphics within user interface (UI)  200 . In this embodiment, as well as others described below, a user may select one or more of the graphics by making contact or touching 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 contact may include a gesture, such as 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 the device  100 . In some embodiments, inadvertent contact with a graphic may not select the graphic. For example, a swipe gesture that sweeps over an application icon may not select the corresponding application when the gesture corresponding to selection is a tap. 
     The device  100  may also include one or more physical buttons, such as “home” or menu button  204 . As described previously, the menu button  204  may be used to navigate to any application  136  in a set of applications that may be executed on the device  100 . Alternatively, in some embodiments, the menu button is implemented as a soft key in a GUI in touch screen  112 . 
     In one embodiment, the device  100  includes a touch screen  112 , a menu button  204 , a push button  206  for powering the device on/off and locking the device, volume adjustment button(s)  208 , a Subscriber Identity Module (SIM) card slot  210 , a head set jack  212 , and a docking/charging external port  124 . The push button  206  may be 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, the device  100  also may accept verbal input for activation or deactivation of some functions through the microphone  113 . 
       FIG. 3A  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, the 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). The 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. The communication buses  320  may include circuitry (sometimes called a chipset) that interconnects and controls communications between system components. The device  300  includes an input/output (I/O interface  330  comprising a display  340 , which is typically a touch screen display. The I/O interface  330  also may include a keyboard and/or mouse (or other pointing device)  350  and a touchpad  355 . Memory  370  includes high-speed random access memory, such as DRAM, SRAM, DDR RAM or other random access solid state memory devices; and may include 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  may optionally include one or more storage devices remotely located from the CPU(s)  310 . In some embodiments, memory  370  stores programs, modules, and data structures analogous to the programs, modules, and data structures stored in the memory  102  of portable multifunction device  100  ( FIG. 1 ), or a subset thereof. Furthermore, memory  370  may store additional programs, modules, and data structures not present in the memory  102  of portable multifunction device  100 . For example, memory  370  of device  300  may store 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 ) may not store these modules. 
     Each of the above identified elements in  FIG. 3A  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. 
     In some embodiments, memory  370  stores contact/motion module  130 . In some embodiments, the contact/motion module  130  includes an event handler  361  that incorporates an event log  366 . The event log  366  may include one or more event log entries, e.g., event log entry  1   366 - 1 , event log entry n  366 - 3 , etc. Event handler  361  will be discussed in greater detail below. 
       FIG. 3B  illustrates an exemplary block diagram of a contact motion module event handler  361  and event log entry structure  367 . 
     Contact motion module event handler  361  is implemented with one or more submodules, which in this example includes contact event jitter reduction submodule  362 , which in turn, may be implemented with one or more submodules. Contact event jitter reduction submodule  362  includes state machine  363  (discussed below with reference to  FIG. 3C ), event log management submodule  365 , and one or more contact event jitter reduction submodule variables  364 . In this example, contact event jitter reduction submodule variables  364  include a first predefined distance threshold  364 - 1 , a second predefined distance threshold  364 - 2 , and a predefined time threshold  364 - 3 . These variables will be discussed in greater detail below with reference to  FIGS. 5A-5L  and  6 A- 6 C. 
     Event log management submodule  365  is used to create, populate, and manage an event log  366  of contact, touch, and/or motion events on the touch-sensitive surface of a device such as portable multifunction device  100 . Event log management submodule  365  creates one or more event log entries in the event log  366 , e.g., event log entry  1   366 - 1 , event log entry  2   366 - 2 , and event log entry n  366 - 3 , in response to the contact motion module  130  detecting and/or determining contact, touch, and/or motion events on the touch-sensitive surface (e.g., determining if contact has occurred, such as detecting a finger-down event; determining if there is movement of the contact and tracking the movement across the touch-sensitive surface, such as detecting one or more finger-dragging events; and determining if the contact has ceased, such as detecting a finger-up event or a break in contact). 
     Event log entries, such as event log entry n  366 - 3 , may be created by the event log management submodule  365  in the form of exemplary event log entry structure  367 , which contains one or more of the following. Event log entry structure  367  contains an event state  367 - 1  (optional), that tracks what state the contact event jitter reduction submodule&#39;s state machine  363  is in at the time of the event corresponding to the current event log entry. In some embodiments, event state  367 - 1  may also track the last known state of the state machine  363 . Event log entry structure  367  may also contain an event ID  367 - 2  (optional), which is a unique event serial number so that the order of event log entries may be easily ascertained. Event log entry structure  367  may also contain contact event specific fields  367 - 3 , including contact location data  367 - 4 , which stores information regarding the contact location on the touch-sensitive surface, and contact time data  367 - 5 , which stores information what time the contact was detected or determined to be on the touch-sensitive surface. 
       FIG. 3C  illustrates an exemplary contact event jitter reduction submodule state machine diagram associated with state machine  363  that may be implemented as part of contact event jitter reduction submodule  362 . The state machine  363  in contact event jitter reduction submodule  362  is used to track the information processing flow of how and when to move or adjust user interface objects on the display in accordance with contact detection, movement, pauses in motion, and liftoff. Contact event jitter reduction submodule state machine diagram  363  includes four states: contact detected  377 , contact movement detected  379 , contact pause detected  396 , and contact liftoff detected  393 . 
     For purposes of brevity, each state in contact event jitter reduction submodule state machine diagram  363  is described as “detected,” though this may include determining that a contact is any of: on the touch-sensitive surface, moved over the touch-sensitive surface, is paused at a location on the touch-sensitive surface, or has been removed from the touch-sensitive surface. 
     After detecting that a contact is on the touch-sensitive surface, the state machine  363  enters state contact detected  377 . After detecting movement  378  of the contact on the touch-sensitive surface, the state machine  363  enters state contact movement detected  379 . If the contact moves less than a first predefined threshold distance (e.g., 3, 5, 10, or 15 pixels, or any suitable, predefined distance over the touch-sensitive surface), the state machine  363  remains (via path  391 ) in state contact movement detected  379 , and no objects on the display are moved. If the contact moves more than (or in some implementations, an amount equal to) the first predefined threshold distance  364 - 1 , the state machine  363  remains (via path  391 ) in state contact movement detected  379 , and any objects on the display are moved or adjusted at the next event. As long as continued motion of the contact is detected, the state machine  363  remains in state contact movement detected  379 . 
     After detecting a pause of more than a predefined time threshold  364 - 3  in the contact&#39;s motion on the touch-sensitive surface (e.g., less than 1.2 seconds, less than a second, or less than half a second, or any suitable, predefined duration), the state machine transitions to state contact pause detected  396  via path  394 . While no motion of the contact is detected, i.e., the contact remains paused, the state machine  363  remains in contact pause detected  396  via path  397 . If contact liftoff is detected, the state machine  363  transitions to state contact liftoff detected  393  via path  398 . When a movement of greater than a second predefined distance threshold  364 - 2  (e.g., 3 pixels, 4 pixels, 5 pixels, or any suitable, predefined distance over the touch-sensitive surface) is detected however, the state machine  363  returns to state contact movement detected  379  via path  395 , and any objects on the display are moved or adjusted at the next event. 
     When the state machine is in state contact movement detected  379 , and a contact liftoff event is detected, the state machine  363  transitions to state contact liftoff detected  393  via path  392 , and any objects on the display are not moved or adjusted. This occurs because the objects on the display would not be moved or adjusted until the next movement event. But, since liftoff has occurred, there will be no more motion events for this given contact. As a result, any jitter of the object associated with liftoff is suppressed. 
     Attention is now directed towards embodiments of user interfaces (“UI”) that may be implemented on a portable multifunction device  100 . 
       FIGS. 4A and 4B  illustrate exemplary user interfaces for a menu of applications on a portable multifunction device  100  in accordance with some embodiments. Similar user interfaces may be implemented on device  300 . In some embodiments, user interface  400 A 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:
           Phone  138 , which may include an indicator  414  of the number of missed calls or voicemail messages;   E-mail client  140 , which may include an indicator  410  of the number of unread e-mails;   Browser  147 ; and   Music player  146 ; and   
           Icons for other applications, such as:
           IM  141 ;   Image management  144 ;   Camera  143 ;   Video player  145 ;   Weather  149 - 1 ;   Stocks  149 - 2 ;   Workout support  142 ;   Calendar  148 ;   Calculator  149 - 3 ;   Alarm clock  149 - 4 ;   Dictionary  149 - 5 ; and   User-created widget  149 - 6 .   
               

     In some embodiments, user interface  400 B includes the following elements, or a subset or superset thereof:
           402 ,  404 ,  405 ,  406 ,  141 ,  148 ,  144 ,  143 ,  149 - 3 ,  149 - 2 ,  149 - 1 ,  149 - 4 ,  410 ,  414 ,  138 ,  140 , and  147 , as described above;   Map  154 ;   Notes  153 ;   Settings  412 , which provides access to settings for the device  100  and its various applications  136 , as described further below;   Video and music player module  152 , also referred to as iPod (trademark of Apple, Inc.) module  152 ; and   Online video module  155 , also referred to as YouTube (trademark of Google, Inc.) module  155 .       

       FIG. 4C  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 ). Although many of the examples which follow will be given with reference to inputs on a 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. 4C . In some embodiments the touch sensitive surface (e.g.,  451  in  FIG. 4C ) has a primary axis (e.g.,  452  in  FIG. 4C ) that corresponds to a primary axis (e.g.,  453  in  FIG. 4C ) on the display (e.g.,  450 ). In accordance with these embodiments, the device detects contacts (e.g.,  460  and  462  in  FIG. 4C ) with the touch-sensitive surface  451  at locations that correspond to respective locations on the display (e.g., in  FIG. 4C   460  corresponds to  468  and  462  corresponds to  470 ). In this way, user inputs (e.g., contacts  460  and  462 ) detected by the device on the touch-sensitive surface (e.g.,  451  in  FIG. 4C ) are used by the device to manipulate the user interface on the display (e.g.,  450  in  FIG. 4C ) of the multifunction device when the touch-sensitive surface is separate from the display. It should be understood that similar methods may be 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 may be 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 may be 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 may be used simultaneously, or a mouse and finger contacts may be used simultaneously. 
     Attention is now directed towards embodiments of user interfaces (“UI”) and associated processes that may be implemented on a multifunction device with a display and a touch-sensitive surface, such as device  300  or portable multifunction device  100 . 
       FIGS. 5A-5L  illustrate exemplary user interfaces for reducing jitter associated with user contacts on touch-sensitive surfaces in accordance with some embodiments. The user interfaces in these figures are used to illustrate the processes described below, including the processes in  FIGS. 6A-6C . 
     In  FIGS. 5A-5L , some finger contact movement sizes, as well as predefined distance thresholds, may be grossly exaggerated for illustrative purposes. No depiction in the figures bearing on predefined distance thresholds or finger contact movements should be taken as a requirement or limitation for the purpose of understanding sizes and scale associated with the methods and devices disclosed herein. 
     UI  500 A ( FIG. 5A ) depicts an exemplar user interface UI  500 A displayed on multifunction device  100 . The user interface includes user interface elements that are moveable objects, i.e., circle  501 , rectangle  502 , and diamond  503 . Near a corner of rectangle  502 , a user has made, and the device has detected, a finger contact  505  on the touch screen  112 . Finger contact  505  has a centroid  507  that is substantially at the center of the finger contact  505 . A first predefined distance threshold away from centroid  507  is depicted by line  509  and perimeter  511 . Finger contact  505 , centroid  507 , line  509 , and perimeter  511  are depicted here for purposes of illustration. While any or all these features may actually be displayed in some embodiments, they will not be displayed in others. 
     UI  500 A also depicts that device  100  detects a first movement  513  of finger contact  505 . A first movement can be a movement of any magnitude that is less than the first predefined distance threshold, and the first movement can be in any direction. While not depicted in UI  500 A, one or more event log entries, such as event log entry n  366 - 3 , may be created by the event log management submodule  365 . A movement, such as the first movement, can correspond to a single event log entry in the event log or a movement may be defined by multiple entries in the event log. 
     UI  500 B ( FIG. 5B ) illustrates that the first movement  513  in UI  500 A has moved the finger contact  505  and centroid  507  closer to the perimeter  511  that demarks the first predefined distance threshold. Moveable object rectangle  502 , however, has not moved because the first movement  513  in UI  500 A did not exceed the first predefined distance threshold (marked by perimeter  511 ). Rather, rectangle  502  is maintained at the same location. 
     UI  500 C-UI  500 E ( FIGS. 5C-5E ) illustrate another movement  515  of the finger contact  505 , and associated movement of the rectangle  502  in accordance with the movement  515 . In UI  500 C, the movement  515 - 1  of the finger contact  505  exceeds the first predefined distance threshold (marked by perimeter  511 ). UI  500 D ( FIG. 5D ) illustrates subsequent movement  515 - 2  of the finger contact  505 , which continues after the first predefined distance threshold has been exceeded (i.e., the movement  515 - 1  of finger contact  505  in UI  500 C happens first and exceeds the first predefined distance threshold, then the continued movement  515 - 2  of finger contact  505 —or a discrete, second movement of finger contact  505 —is depicted in UI  500 D). In this example, movement  515  occurs while the finger contact  505  is still on touch screen  112  after first movement  513  and a finger liftoff event has not yet occurred. 
     UI  500 E illustrates that the movements  515  depicted in UI  500 C and UI  500 D have moved rectangle  502  to a new location. Notably, the movement of the rectangle  502  is delayed in UI  500 C until after detecting the additional, second movement  515 - 2  of the finger contact  505  depicted in UI  500 D. In other words, the rectangle  502  would move in accordance with the movement  515 - 2  of finger contact  505  on the touch screen  112 , starting with the movement  515 - 2  depicted in UI  500 D. 
     UI  500 E also illustrates that, in some embodiments, the first predefined distance threshold becomes irrelevant for the current finger contact once motion is detected that exceeds the first predefined distance threshold. Thus, for clarity, the perimeter  511  is no longer displayed in the following figures. 
     UI  500 E also depicts that a pause in movement of the finger contact  505  has been detected. 
     UI  500 F ( FIG. 5F ) illustrates that in response to detecting the pause in movement of the finger contact  505 , the device maintains display of the rectangle  502  at a fixed location, i.e., the paused location on the display. UI  500 F also illustrates a second predefined distance threshold away from centroid  507 . The second predefined distance threshold is depicted by line  519  and perimeter  517 . As with UI  500 A, finger contact  505 , centroid  507 , line  519 , and perimeter  517  are depicted here for purposes of illustration, and may be optionally displayed in some embodiments. 
     UI  500 G-UI  500 H ( FIGS. 5G-5H ) illustrate a movement  520  that is less than the second predefined threshold, i.e., the movement  520  does not cross over the perimeter  517 . Accordingly, as shown in UI  500 H, the device maintains the display of the rectangle  502  at the paused location on the display, even though finger contact  505  and centroid  507  have moved towards the edge of the perimeter  517  that represents the second predefined distance threshold. 
     UI  500 I-UI  500 K ( FIGS. 5I-5K ) illustrate another movement  522  of the finger contact  505 , and associated movement of the rectangle  502 . In UI  500 I, the movement  522 - 1  of the finger contact  505  exceeds the second predefined distance threshold (marked by perimeter  517 ). UI  500 J ( FIG. 5J ) illustrates the subsequent movement  522 - 2  of the finger contact  505 , which continues after the second predefined distance threshold has been exceeded (i.e., the movement  522 - 1  of finger contact  505  in UI  500 I happens first and exceeds the second predefined distance threshold, then the continued movement  522 - 2  of finger contact  505 —or a discrete, second movement of finger contact  505 —is depicted in UI  500 J). In this example, movement  522  occurs while the finger contact  505  is still on touch screen  112  after first movement  513  and a finger liftoff event has not yet occurred. 
     UI  500 K illustrates that the movements  522  depicted in UI  500 I and UI  500 J have moved rectangle  502  to a new location. Notably, the movement of the rectangle  502  is delayed in UI  500 K until after detecting the additional, second movement  522 - 2  of the finger contact  505  depicted in UI  500 J. In other words, the rectangle  502  would move in accordance with the movement  522  of finger contact  505  on the touch screen  112 , starting with the movement  522 - 2  depicted in UI  500 J. 
     After the movement  522  of the finger contact  505  in  FIGS. 5I and 5J , and a pause in the movement of the finger contact  505  (not depicted), another movement  524  of the finger contact  505  on the touch screen  112  is illustrated in UI  500 K. The movement  524  of the finger contact  505  is less than the second predefined threshold, i.e., the movement  524  does not cross the perimeter  517  that illustrates the size of the second predefined threshold. After detecting movement  524 , liftoff of the finger contact  505  is detected (also not depicted). 
     UI  500 L ( FIG. 5L ) illustrates that in response to detecting liftoff of the finger contact  505 , the device maintains display of the rectangle  502  at the paused location. 
       FIGS. 6A-6C  are flow diagrams illustrating a method  600  of reducing jitter associated with user contacts on touch-sensitive surfaces in accordance with some embodiments. The method  600  is performed at a multifunction device (e.g., device  300 ,  FIG. 3A , or portable multifunction device  100 ,  FIG. 1 ) with a display and a touch-sensitive surface. In some embodiments, the display is a touch screen display and the touch-sensitive surface is on the display. In some embodiments, the display is separate from the touch-sensitive surface. Some operations in method  600  may be combined and/or the order of some operations may be changed. 
     As described below, the method  600  provides an effective way to reduce jitter associated with user contacts on touch-sensitive surfaces in accordance with some embodiments. The method reduces the cognitive burden on a user when using a touch sensitive surface to interact with a user interface because the user does not have to contend with jitter when placing and/or adjusting moveable user interface objects, thereby creating a more efficient human-machine interface. For battery-operated computing devices, enabling a user to place and/or adjust moveable user interface objects faster and more efficiently conserves power and increases the time between battery charges. 
     The device displays ( 602 ) a user interface that includes a moveable object at a first location on the display at a multifunction device with a display and a touch-sensitive surface (e.g., UI  500 A, touch screen  112 , and rectangle  502  in  FIG. 5A ). 
     As discussed above, in some embodiments, the display is a touch screen display and a touch-sensitive surface is on the display ( 604 ) (e.g., portable multifunction device  100 ,  FIG. 1 ). 
     The device detects ( 606 ) a finger contact on the touch-sensitive surface at a location on the touch-sensitive surface that corresponds to the first location of the moveable object on the display (e.g.,  FIG. 5A  finger contact  505 ). As a result, the device creates ( 608 ) an event log entry that corresponds to the finger contact in an event log comprising event log entries, wherein respective event log entries include contact location data and contact time data (e.g., in some embodiments, the event log management submodule  365  shown in  FIG. 3B  creates one or more event log entries in the event log  366 , such as event log entry  1   366 - 1 ). 
     The device detects ( 610 ) a first movement of the finger contact across the touch-sensitive surface (e.g.,  FIG. 5A  movement  513  of finger contact  505 ). 
     The device creates ( 612 ) one or more event log entries that correspond to the first movement of the finger contact (e.g., event log management submodule  365  shown in  FIG. 3B  creates one or more event log entries in the event log  366 ). 
     In some embodiments, the device creates at least one event log entry that corresponds to the first movement of the finger contact. 
     In response to detecting the first movement of the finger contact, when the first movement is less than a first predefined distance threshold (i.e., 5, 10, or 15 pixels, or any suitable, predefined distance over the touch-sensitive surface), the device maintains ( 614 ) display of the moveable object at the first location (e.g.,  FIG. 5B , where rectangle  502  remains in the same location as in  FIG. 5A  despite movement  513  of finger contact  505 ). 
     When the first movement is greater than or equal to the first predefined distance threshold, the device delays ( 616 ) movement of the moveable object from the first location until a second movement of the finger contact after the first movement of the finger contact movement is detected (e.g., as shown in  FIG. 5C , despite movement  515 - 1  of finger contact  505 , rectangle  502  remains the in the same location; in  FIG. 5D , movement  515 - 2  of finger contact  505  is an example of a second movement of the finger contact). The second movement of the finger contact can be a continuation of the first movement of the finger contact. 
     The device creates ( 618 ) one or more event log entries that correspond to the second movement of the finger contact (e.g., the event log management submodule  365  of  FIG. 3B  creates one or more event log entries in the event log  366 , such as event log entry  2   366 - 2 ). 
     In some embodiments, the one or more events corresponding to the second movement of the finger contact occur with no intervening events after the one or more events corresponding to the first movement of the finger contact ( 620 ). 
     After detecting the second movement of the finger contact on the touch-sensitive surface, the device moves ( 622 ) the moveable object on the display in accordance with the movement of the finger contact on the touch-sensitive surface (e.g., as shown in  FIG. 5C , despite movement  515 - 1  of finger contact  505 , rectangle  502  remains the in the same location; movement  515 - 2  of finger contact  505  in  FIG. 5D  causes the rectangle  502  to move in accordance with the finger contact  505  on the touch-sensitive surface, as shown in  FIG. 5E ). 
     In some embodiments, the moveable object is moved on the display in accordance with the first movement of the finger contact on the touch-sensitive surface. In some embodiments, the moveable object is moved on the display in accordance with the second movement of the finger contact on the touch-sensitive surface. In alternate embodiments, the moveable object is moved on the display in accordance with both the first and the second movements of the finger contact on the touch-sensitive surface. In some embodiments, moving the moveable object on the display in accordance with the movement of the finger contact on the touch-sensitive surface is done in response to detecting the second movement of the finger contact on the touch-sensitive surface. 
     In some embodiments, moving the moveable object on the display comprises moving the moveable object in accordance with event log entries that correspond to the first and second movements of the finger contact ( 624 ). 
     After detecting the second movement of the finger contact, the device detects ( 626 ) a pause in movement of the finger contact (e.g.,  FIG. 5E ). The pause is detected in any suitable fashion, e.g., the finger contact moves less than a predefined threshold, the finger contact moves less than a predefined distance during a predefined time, etc. 
     The device creates ( 628 ) one or more event log entries corresponding to the pause in movement of the finger contact (e.g., event log management submodule  365  shown in  FIG. 3B  creates one or more event log entries in the event log  366 , such as event log entry n  366 - n ). 
     In response to detecting the pause in movement of the finger contact, the device maintains ( 630 ) display of the moveable object at a paused location (i.e., the paused location is a fixed location) (e.g.,  FIG. 5F  illustrates that in response to detecting the pause in movement of the finger contact  505 , the device maintains display of the rectangle  502  at the paused location). 
     The device detects ( 632 ) a third movement of the finger contact  505  across the touch-sensitive surface (e.g.,  FIG. 5G  movement  520 ,  FIG. 5I  movement  522 - 1 , or  FIG. 5K  movement  524 ). 
     In response to detecting the third movement of the finger contact, the device creates ( 634 ) one or more event log entries that correspond to the third movement of the finger contact (e.g., event log management submodule  365  shown in  FIG. 3B  creates one or more event log entries in the event log  366 , such as event log entry n  366 - n ). 
     In response to detecting the third movement of the finger contact, when the third movement is less than a second predefined distance threshold, the device maintains ( 636 ) display of the moveable object at the paused location (e.g., in  FIG. 5H , the device maintains the display of the rectangle  502  at the paused location on the display, even though finger contact  505  and centroid  507  have moved towards the edge of the perimeter  517  that represents the second predefined distance threshold). The second predefined distance threshold may be any suitable, predefined distance over the touch-sensitive surface, e.g., 3 pixels, 4 pixels, 5 pixels, etc. 
     In some embodiments, the first predefined distance threshold is equivalent to the second predefined distance threshold ( 638 ). In alternative embodiments, the first predefined distance threshold is greater than the second predefined distance threshold ( 640 ). 
     In response to detecting the third movement of the finger contact, when the third movement is greater than or equal to the second predefined distance threshold, the device delays ( 642 ) movement of the moveable object from the paused location until a fourth movement of the finger contact after the third movement of the finger contact movement is detected (e.g.,  FIG. 5I  illustrates that in response to detecting the third movement  522 - 1  of the finger contact  505 , the device maintains the display location of the rectangle  502 , then in  FIG. 5J , the fourth movement  522 - 2  is detected). 
     In some embodiments, the one or more events corresponding to the fourth movement of the finger contact occur with no intervening events after the one or more events corresponding to the third movement of the finger contact ( 644 ). It is noted that in the event that one or more intervening events (e.g., liftoff of the finger contact, or user selection of another object via another gesture) were to occur after the third movement of the finger contact, the process would resume back at  602 . 
     In response to detecting the fourth movement, the device creates ( 646 ) one or more event log entries that correspond to the fourth movement of the finger contact (e.g., event log management submodule  365  shown in  FIG. 3B  creates one or more event log entries in the event log  366 , such as event log entry n  366 - n ). 
     After detecting the fourth movement of the finger contact on the touch-sensitive surface, and in response to detecting the fourth movement of the finger contact, the device moves ( 648 ) the moveable object on the display in accordance with the movement of the finger contact on the touch-sensitive surface (e.g.,  FIG. 5I , despite movement  522 - 1  of finger contact  505 , rectangle  502  remains the in the same location,  FIG. 5J  includes movement  522 - 2  of finger contact  505 , FIG.  5 JK depicts that the rectangle  502  has moved in accordance with the finger contact on the touch-sensitive surface). 
     In some embodiments, the moveable object is moved on the display in accordance with the third movement of the finger contact on the touch-sensitive surface. In some embodiments, the moveable object is moved on the display in accordance with the fourth movement of the finger contact on the touch-sensitive surface. In alternate embodiments, the moveable object is moved on the display in accordance with both the third and the fourth movements of the finger contact on the touch-sensitive surface. 
     After detecting the third movement of the finger contact, when the third movement is less than the second predefined distance threshold, the device detects ( 650 ) liftoff of the finger contact (e.g.,  FIG. 5K  movement  524 , liftoff not depicted), and the device creates ( 652 ) one or more event log entries corresponding to the liftoff of the finger contact (e.g., event log management submodule  365  shown in  FIG. 3B  creates one or more event log entries in the event log  366 , such as event log entry n  366 - n ). 
     The device then maintains ( 654 ) display of the moveable object at the paused location (e.g.,  FIG. 5L  illustrates that in response to detecting liftoff of the finger contact  505 , the device maintains display of the rectangle  502  at the paused location). 
     The methods discussed above permit moveable objects to be placed on the display with single pixel accuracy. 
     The steps in the information processing methods described above may be implemented by running one or more functional modules in information processing apparatus such as general purpose processors or application specific chips. These modules, combinations of these modules, and/or their combination with general hardware (e.g., as described above with respect to  FIGS. 1A ,  1 B and  3 A) comprise additional embodiments of the present invention. 
     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 invention 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 invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.