Patent Publication Number: US-8542206-B2

Title: Swipe gestures for touch screen keyboards

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 11/766,929, filed Jun. 22, 2007, which is incorporated herein by reference in its entirety. 
     This is related to the following U.S. patents and patent applications, each of which is hereby incorporated by reference in its entirety:
         U.S. Pat. No. 6,323,846, titled “Method and Apparatus for Integrating Manual Input,” issued Nov. 27, 2001;   U.S. patent application Ser. No. 10/840,862, titled “Multipoint Touchscreen,” issued May 6, 2004;   U.S. Provisional Patent Application No. 60/804,361, titled “Touch Screen Liquid Crystal Display,” filed Jun. 9, 2006;   U.S. Provisional Patent Application No. 60/883,979, titled “Touch Screen Liquid Crystal Display,” filed Jan. 8, 2007;   U.S. patent application Ser. No. 11/367,749, titled “Multi-functional Hand-held Device,” filed Mar. 3, 2006;   U.S. patent application Ser. No. 11/228,737, titled “Activating Virtual Keys of a Touch-Screen Virtual Keyboard,” filed Sep. 16, 2005;   U.S. patent application Ser. No. 11/228,700, titled “Operation of a Computer with a Touch Screen Interface,” filed Sep. 16, 2005;   U.S. Pat. No. 6,677,932, titled “System and Method for Recognizing Touch Typing Under Limited Tactile Feedback Conditions,” issued Jan. 13, 2004; and   U.S. Pat. No. 6,570,557, titled “Multi-touch System and Method for Emulating Modifier Keys Via Fingertip Chords,” issued May 27, 2003.       

    
    
     BACKGROUND 
     The present invention relates generally to input systems, methods, and devices, and more particularly, to systems, methods, and devices for interpreting manual swipe gestures as input in connection with touch-screen keyboards. 
     There currently exist various types of input devices for performing operations in electronic devices. The operations, for example, may correspond to moving a cursor and making selections on a display screen. The operations may also include paging, scrolling, panning, &#39;zooming, etc. The input devices may include, for example, buttons, switches, keyboards, mice, trackballs, pointing sticks, joy sticks, touch surfaces (including touch pads and touch screens, etc.), and other types of input devices. 
     Various types of touch surfaces and touch screens are described in the related applications cross-referenced above. Touch screens may include a display, a touch panel, a controller, and a software driver. The touch panel may include a substantially transparent panel that incorporates touch-sensing circuitry. The touch panel can be positioned in front of a display screen or constructed integrally with a display screen so that the touch sensitive surface corresponds to all or a portion of the viewable area of the display screen. The touch panel can detect touch events and send corresponding signals to the controller. The controller can process these signals and send the data to the computer system. The software driver can translate the touch events into computer events recognizable by the computer system. Other variations of this basic arrangement are also possible. 
     The computer system can comprise a variety of different device types, such as a pocket computer, handheld computer, or wearable computer (such as on the wrist or arm, or attached to clothing, etc.). The host device may also comprise devices such as personal digital• assistants (PDAs), portable media players (such as audio players, video players, multimedia players, etc.), game consoles, smart phones, telephones or other communications devices, navigation devices, exercise monitors or other personal training devices, or other devices or combination of devices. 
     In some embodiments, touch screens can include a plurality of sensing elements. Each sensing element in an array of sensing elements (e.g., a touch surface) can generate an output signal indicative of the electric field disturbance (for capacitance sensors), force (for pressure sensors), or optical coupling (for optical sensors) at a position on the touch surface corresponding to the sensor element. The array of pixel values can be considered as a touch, force, or proximity image. Generally, each of the sensing elements can work independently of the other sensing elements so as to produce substantially simultaneously occurring signals representative of different points on the touch screen  120  at a particular time. 
     Recently, interest has developed in touch-sensitive input devices, such as touch screens, for hand-held or other small form factor devices. For example U.S. patent application Ser. No. 11/367,749, titled “Multi-functional Hand-held Device,” discloses a multi-functional hand-held device that integrates a variety of device functionalities into a single device having a hand-held form factor. In such applications, touch screens can be used for a variety of forms of input, including conventional pointing and selection, more complex gesturing, and typing. 
     Conventional touch-typing techniques may be difficult to use on touch-screen based small form factor devices. As a result, users often use “hunt and peck” typing techniques to input text into such devices. Various techniques for enhancing such textual input are disclosed in U.S. patent application Ser. Nos. 11/367,749; 11/228,737; and 11/228,700 and U.S. Pat. Nos. 6,677,932 and 6,570,557 incorporated by reference herein. It is believed that textual input on virtual keyboards can be further enhanced. 
     SUMMARY 
     The present invention can relate, for example, to a method of interpreting swipe gesture input to a device having a touch-sensitive input. The touch-sensitive input can include a virtual keyboard area, in which taps of a touch object generate text input. The method can include detecting a swipe gesture across the virtual keyboard, determining a direction of the swipe gesture, and performing a predetermined function determined by the direction of the swipe gesture. A swipe gesture can include a touchdown of a touch object followed by a sliding motion of the touch object across the virtual keyboard. 
     Detecting a swipe gesture can include acquiring touch image data from the touch-sensitive device, processing the image to generate one or more finger path events, determining a displacement of the one or more finger path events, and detecting a swipe gesture if the displacement exceeds a predetermined threshold. If the displacement does not exceed the threshold, the input can be interpreted as a conventional tap. The time of the motion associated with the input can also be compared to a maximum swipe gesture timeout threshold. If the timeout threshold is exceeded, the input can be interpreted as a conventional tap. 
     Determining the direction of a swipe gesture can include comparing a magnitude of a vertical displacement of the swipe gesture to a magnitude of a horizontal displacement of the swipe gesture. A swipe gesture can be interpreted as a vertical swipe gesture if the vertical displacement is greater than the horizontal displacement. Alternatively, a swipe gesture can be interpreted as a horizontal swipe gesture if the vertical displacement is less than the horizontal displacement. Alternatively, determining the direction of a swipe gesture can include comparing a ratio of the vertical displacement of the swipe gesture to the horizontal displacement of the swipe gesture to a predetermined threshold. A swipe gesture can be interpreted as a vertical swipe gesture if the ratio is greater than the threshold, while a swipe gesture can be interpreted as a horizontal swipe gesture if the ratio is less than the threshold. 
     A vertical swipe gesture can be interpreted as an upward or downward swipe gesture depending on the sign (ie., positive or negative) of the vertical displacement. A horizontal swipe gesture can be interpreted as a rightward or leftward swipe gesture depending on the sign ((ie., positive or negative) of the horizontal displacement. 
     A variety of functions can be invoked using the swipe gestures. For example, the swipe gestures can be used for spacing, erasing, or punctuation insertion. Feedback can be presented to the user indicating the function performed. The functions performed by particular swipe gestures may also be customized by the user. 
     Particular swipe gestures that can be linked to particular functions can include using a rightward swipe gesture to invoke a space, using a leftward swipe gesture to invoke a backspace, using a downward swipe gesture to invoke a carriage return and/or a new line, and using an upward swipe gesture to invoke a shift. Additionally, a second upward swipe gesture can be used to invoke a caps lock. The second upward swipe can either be performed sequentially to the first upward swipe or concurrently with the first upward swipe, i.e., as a multi-fingered swipe gesture. Other alternative mappings of swipe gestures to functions include using an upward swipe gesture to insert a punctuation character, such as a period or apostrophe. 
     Multi-fingered swipe gestures can be used to invoke additional functionality. For example, a multi-fingered leftward swipe can be used to invoke deletion of a word in a manner analogous to using a leftward swipe gesture as a backspace. Similarly, a multi-fingered rightward swipe can be used to insert a punctuation character and a space, such as a period and a space at the end of a sentence. Swipe gestures can also be used to invoke alternative keyboards containing punctuation, numbers, or special symbols of various types. 
     The present invention can also relate to a computer system including a multi-touch interface that has been adapted and/or programmed to detect and process swipe gesture input in the various ways described above. The computer system can take the form of a desktop computer, a tablet computer, a notebook computer, a handheld computer, a personal digital assistant, a media player, a mobile telephone, and combinations of one or more of these items. The multi-touch interface can include a touch screen. 
     In some embodiments, the computer system can include a touch image processor that receives touch image data from the multi-touch interface and generates finger path tracking events. These finger path tracking events can be processed by a keyboard tap recognizer and a keyboard slide recognizer, which generate key tap and swipe events, respectively, in response to the touch input received. A keyboard input manager can receive the key tap events and the keyboard swipe events and generates text events for an application running on the computer system and feedback popup graphics to be displayed on a display of the computer system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein. 
         FIGS. 1A-1B  depict a front plan view of a user typing using an exemplary electronic device with touch screen display in accordance with an embodiment of the present invention. 
         FIGS. 2A-2C  depict a user invoking a backspace using a leftward swipe gesture in accordance with an embodiment of the present invention. 
         FIG. 3  depicts a user typing in accordance with an embodiment of the present invention. 
         FIGS. 4A-4C  depict a user invoking a space using a rightward swipe gesture in accordance with an embodiment of the present invention. 
         FIGS. 5A-5C  depict a user invoking a carriage return/new line using a downward swipe gesture in accordance with an embodiment of the present invention. 
         FIGS. 6A-6D  depict a user invoking a shift using an upward swipe gesture in accordance with an embodiment of the present invention. 
         FIG. 7  depicts a user invoking a caps lock using two sequential upward swipe gestures in accordance with an embodiment of the present invention. 
         FIG. 8  depicts a user invoking the display of an alternative keyboard using a swipe gesture in accordance with an embodiment of the present invention. 
         FIG. 9  depicts a block diagram of an exemplary swipe recognition system in accordance with various embodiments of the present invention. 
         FIG. 10  depicts a flow chart of an exemplary swipe gesture detection technique in accordance with various embodiments of the present invention. 
         FIGS. 11A-11C  depict an alternative method of distinguishing vertical swipes from horizontal swipes in accordance with various embodiments of the present invention. 
         FIG. 12  depicts a simplified block diagram of a computer system implementing one or more embodiments of the present invention. 
         FIG. 13  depicts various computer form factors that may be used in accordance with embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Reference is now made to  FIG. 1A , which depicts a front plan view of an exemplary electronic device  100  that implements a touch screen-based virtual keyboard. Electronic device  100  includes a display  110  that also incorporates a touch screen. The display  110  can be configured to display a graphical user interface (GUI). The GUI may include graphical and textual elements representing the information and actions available to the user. For example, the touch screen may allow a user to move an input pointer or make selections on the GUI by simply pointing at the GUI on the display  110 . 
     As depicted in  FIG. 1A , the GUI can be adapted to display a program application that requires text input. For example, a chat or messaging application is depicted. For such an &#39;application, the display can be divided into two basic areas. A first area  112  can be used to display information for the user, in this case, the messages the user is sending, represented by balloon  113   a  and the messages he is receiving from the person he is communicating with, represented by balloon  113   b . First area  112  can also be used to show the text that the user is currently inputting in text field  114 . First area  112  can also include a virtual “send” button  115 , activation of which causes the messages entered in text field  114  to be sent. 
     A second area can be used to present to the user a virtual keyboard  116  that can be used to enter the text that appears in field  114  and is ultimately sent to the person the user is communicating with. Touching the touch screen at a “virtual key”  117  can cause the corresponding character to be generated in text field  114 . The user can interact with the touch screen using a variety of touch objects, including, for example, a finger, stylus, pen, pencil, etc. Additionally, in some embodiments, multiple touch objects can be used simultaneously. 
     Because of space limitations, the virtual keys may be substantially smaller than keys on a conventional keyboard. To assist the user, “top hats”  118  can indicate to the user what key is being pressed. Additionally, not all characters that would be found on a conventional keyboard may be presented. Such special characters can be input by invoking an alternative virtual keyboard. For example, a virtual key  119  can be used to invoke an alternative keyboard including numbers and punctuation characters not present on the main virtual keyboard. Additional virtual keys for various functions may be provided. For example, a virtual shift key  120 , a virtual space bar  121 , a virtual carriage return or enter key  122 , and a virtual backspace key (not shown in  FIG. 1A ,  123  in  FIG. 1B ) are provided in the illustrated embodiment. 
     To provide more convenient use of certain keys, for example, erasing and basic punctuation insertion, directional swipes (also referred to herein as “swipe gestures”) over the alphabetic keys can be used as an alternative to striking certain keys. Because the Space and Backspace keys are quite frequently used, they are logical candidates for the rightward and leftward swipes, respectively. Leftward and rightward swipes intuitively match the cursor travel caused by these symbols. Following this cursor movement analogy, the Enter/Return may be invoked by a downward swipe, and a Shift/Caps may be invoked by an upward swipe. Alternatively, as the Enter and Shift functions may be less frequently invoked, these may be substituted for other functions as well. One alternative mapping for the upward swipe, for example, could be to activate an alternative numeric and punctuation keypad or a particular punctuation symbol like an apostrophe or period. 
     Interspersing the tedious task of typing using the small keys with swipes that do not require a specific point of origin can give users a nice break from the sensorimotor and cognitive load of targeting very tiny keys. Additionally, this can allow users to keep their eyes focused and fingers on the central alphabetic layout, avoiding thumb contortions to hit space, backspace, shift and return keys that may be located in the bottom row or corners. 
     An example of the usage of such a swipe gestures can be seen with respect to  FIGS. 1A through 8 . In  FIG. 1A , the user is entering the text “ok” in response to a query received through a chat application. By tapping finger  124  on the area corresponding to the letter “o” on virtual keyboard  116  the letter “o” is entered in text field  114 . A top hat  118  with a representation of the letter “o” is displayed providing feedback to the user. As shown in  FIG. 1B , the user then attempts to tap the letter “k” using finger  124 . However, the user inadvertently taps the letter “j” as indicated by top hat  125 . Although this typographical error could be corrected through the use of virtual backspace key  123 , the backspace function can also be invoked by the rightward swipe illustrated in  FIGS. 2A through 2C . 
     As illustrated in  FIGS. 2A through 2C , the backspace function can be invoked with a leftward swipe of finger  124 . As described in greater detail below, the swipe can include a touchdown of finger  124  in the virtual keyboard  116  followed by a sliding leftward motion in contact with the touch-sensitive surface ( FIG. 2B ). After the leftward motion, the finger is lifted ( FIG. 2C ) and the backspace function is executed, removing the erroneously typed letter “j.” Optionally, a top hat  126  can be used to indicate to the user that the backspace function was performed. Other visual feedback, such as highlighting or flashing the key corresponding to the backspace gesture can also be used. The top hats can also have graphic arrows or other effects indicating and reminding the user of the direction of swipe that can activate that key. 
     As illustrated in  FIG. 3 , the user can now enter the “k” of the “ok” by tapping the appropriate region of virtual keyboard  116 . A top hat  127  indicates that the letter “k” was pressed, as well as the appearance of the “k” character in text field  114 . A space following the “ok” may be entered using a rightward swipe as illustrated in  FIGS. 4A through 4C . Like the leftward swipe, the rightward swipe comprises a touchdown of finger  124  in virtual keyboard  116  (illustrated in  FIG. 4A ). This touchdown is followed by a rightward swipe across the virtual keyboard area  116  (illustrated in  FIG. 4B ). After liftoff of the finger, a space appears in text field  114 , and a top hat  128  (or other visual feedback as discussed above) can be used to indicate that the space was entered. 
     Use of a downward swipe to enter a carriage return and new line is illustrated in  FIGS. 5A through 5C . Again, the downward swipe includes a touchdown of the finger  114  in virtual keyboard  116  (illustrated in  FIG. 5A ). This touchdown is followed by a downward motion of the finger across the virtual keyboard (illustrated in  FIG. 5B ). The insertion of the carriage return and new line after liftoff of the finger is indicated to the user by the appearance of the new line in text field  114  and the appearance of top hat  129  indicating that the return was invoked (illustrated in  FIG. 5C ). 
     Use of an upward swipe to invoke a shift for the entry of capital letters is illustrated in  FIGS. 6A through 6D . As illustrated in  FIG. 6A , the swipe gesture starts with a touchdown of finger  124  in virtual keyboard area  116 . The touchdown is followed by an upward slide across the virtual keyboard area  116 , as illustrated in  FIG. 6B . As illustrated in  FIG. 6C , liftoff of the finger following the upward slide invokes the shift, as indicated by display of the top hat  130 . A subsequent tap of a virtual key (e.g., the letter “c”) results in a capital “C” being entered in the text field  114 . 
     In a variation of this arrangement, two upward swipes can invoke a Caps Lock, i.e., a shift that applies capitalization to a sequence of typed letters. The two upward swipes can be performed sequentially or can be performed simultaneously, i.e., as a two-fingered upward swipe. Such a scenario is illustrated in  FIG. 7 . Other numbers of swipes or numbers of fingers could also be used. Alternatively, an upward stroke can be used to invoke an alternative keyboard. As noted above, small virtual keyboards may not include numeric and punctuation characters, so an upward swipe as described above could cause a second virtual keyboard  131  to be displayed, the second virtual keyboard including numeric and punctuation characters or other special characters such as alternative alphabets, special symbols, etc. 
     The examples above have focused primarily on the use of single-finger swipe gestures. However, other numbers of fingers could also be used to implement these functions. Additionally, multiple-finger swipes could be used to implement additional functions. For example, a single-finger leftward swipe could be used to invoke a backspace key, which would delete a previous character. A two-finger leftward swipe could be used to delete a previously entered word. A three-finger leftward swipe could be used to delete a line. (In each case, the number of fingers can vary.) Similarly, a single finger rightward swipe could be used to invoke a space, while a two-finger rightward swipe could be used to invoke a period and a space, ending a sentence. Alternatively, a two-finger rightward swipe could be used to accept a word completion suggestion offered by the application. Similarly, a three-finger rightward swipe could be used to display a listing of possible word completions. (Again, the number of fingers can vary.) 
     Multi-finger swipes can also apply to swipes in the upward and downward directions. For example, a single-finger upward swipe could invoke a shift that applies only to the next entered character. A two-finger upward swipe could invoke a caps lock mode or an accented character mode (e.g., for foreign languages). A three-finger upward swipe could invoke an accent mode or an alternative keypad mode (e.g., punctuation, numeric, accented, etc.). Similarly, a single-finger downward swipe can invoke a new line, carriage return, or enter. A two-finger downward swipe can invoke a period (or other punctuation). A three-finger downward swipe can invoke a punctuation pad. (As above, the number of fingers in each case can vary.) 
     As will be appreciated, numerous other variations along these lines are also possible. Additionally, an interface can be provided to permit a user to customize the activity that will be performed in response to various swipe gestures. 
     Having described a user&#39;s interaction with the system, the operation of such a system may be understood with reference to  FIGS. 9 and 10 .  FIG. 9  depicts a block diagram of a system implementing various aspects of the present invention. In  FIG. 9 , data structures and signals are represented with elliptical blocks. As would be understood by one skilled in the art, these data structures and signals can take a variety of forms depending on a particular implementation. In  FIG. 9 , processors for the data and signals are depicted with rectangular blocks. These processors can be implemented in hardware, software, firmware, or combinations thereof. Examples of data structures, signals, hardware, software, and firmware that can be used to implement the teachings of the present disclosure appear in the various references incorporated above. 
     As shown in  FIG. 9 , a handheld device  100  can incorporate a touch screen  110 . The touch screen detects touch events, which can be encoded in the form of touch image data  901 . This touch image data is submitted to touch image processor  902 . Details regarding touch image acquisition and processing are described in U.S. Pat. No. 6,323,846, which incorporated by reference. For present purposes, it is sufficient to understand that the processing of the touch image results in one or more finger path tracking events  903 . These finger path tracking events can be submitted to two separate processes, keyboard tap recognizer  904  and keyboard slide recognizer  905 . 
     Keyboard tap recognizer  904  can serve to translate taps on the virtual keyboard surface in to key tap events  906 . These key tap events are submitted to keyboard input manager  907 . Keyboard input manager  907  interprets key tap events  906  and generates text events  908  that are sent to the applications, e.g., the entry of letters into text fields as described above. Keyboard input manager  907  also generates feedback popup graphics  909 , e.g., the top hats showing which letter has been tapped that were described above. 
     Keyboard slide recognizer  905  can serve to recognize the sliding motions that distinguish keyboard taps from swipe gestures. If a swipe is detected, the tap that would have been recognized at the initial contact position of the swipe gesture must be cancelled. This can be accomplished by sending cancel tap signal  910  to keyboard tap recognizer  904 . Keyboard slide recognizer  905  also generates keyboard swipe events  911  that can be submitted to keyboard input manager  907 . As in the case of key taps, keyboard input manager  907  can generate text events  908  as well as pop up graphics  909  that correspond to the detected swipes. 
       FIG. 10  shows a combined flow chart for an implementation of keyboard tap recognizer  904  and keyboard slide recognizer  905 . In block  1001 , a finger path event is retrieved. In block  1002  it is determined if the new path event corresponds to a new touch, e.g., a finger that has just appeared on the surface. If so, the touchdown location and time are captured (block  1003 ), and a path data structure  1004  containing this information is created. If the finger path event is not a new touch, a preexisting path data structure  1005  is updated with the current location and time of the touch. 
     In either case, the path data structure ( 1004  or  1005 ) is submitted to a displacement measurement process (block  1006 ). The displacement measurement process can determine how much the path has moved in both horizontal direction (D[i].x), how much the path has moved in the vertical direction (D[i].y), and over what time (T[i]). The total distance moved can then be compared to a minimum threshold of movement used to determine whether the touch event is a tap or a swipe (block  1007 ). If there is little motion, i.e., less than the threshold, the event is interpreted as a key tap, and the system updates the key choice that corresponds to the location of the finger (block  1008 ). 
     If the motion exceeds the minimum swipe length threshold (block  1007 ), a second test can be performed to determine whether the time of the motion is less than a swipe gesture timeout (block  1009 ). This optional time threshold can be used to allow slower motions to permit a user to fine tune key selection e.g., using the displayed top hats. If the time of the motion is greater than the swipe gesture timeout threshold, i.e., took too long to be a swipe gesture, the event is interpreted as a key tap, and the system updates the key choice that corresponds to the location of the finger (block  1008 ). As an alternative to the time threshold, the system can instead look for an initial velocity at touchdown to distinguish a swipe from a tap. 
     If the path is determined to be a key tap, the key choice currently under the finger is updated (block  1008 ). Then, if a liftoff of the touch is detected (block  1010 ), the final key tap choice is issued (block  1011 ). If a liftoff is not detected (block  1010 ), the next finger path event is detected (block  1001 ), and the process repeats. 
     Alternatively, if the path has been determined to exceed the minimum length threshold for a swipe gesture (block  1007 ) and has been determined to be less than the maximum time threshold for a swipe threshold (block  1009 ), the path can be interpreted as a swipe event. As a result, a cancel key tap signal is generated (block  1012 ). The direction of the swipe gesture can then be determined as follows. 
     The magnitude of the vertical motion of the path displacement can be compared to the magnitude of the horizontal motion of the path displacement (block  1013 ). (Both parameters were determined in block  1006 ). If the total vertical motion is greater than the total horizontal motion, it can determined whether the vertical displacement is positive (upward) (block  1014 ). If so, the event can be interpreted as an upward swipe, and the appropriate action can be invoked (block  1015 ). If the vertical displacement is negative, the event can be interpreted as a downward swipe, and the appropriate action can be invoked (block  1016 ). 
     Alternatively, if the total vertical motion is determined to be less than the total horizontal motion (block  1013 ), it can be determined whether the horizontal displacement is positive (rightward) (block  1017 ). If so, the event can be interpreted as a rightward swipe, and the appropriate action can be invoked (block  1018 ). If the horizontal displacement is negative, the event can be interpreted as a leftward swipe, and the appropriate action can be invoked (block  1019 ). 
     For any of the invoked swipes, i.e., upward swipe (block  1015 ), downward swipe (block  1016 ), rightward swipe (block  1018 ), or leftward swipe (block  1019 ), the swipe action can be repeated if the touch is held down for a short period of time (block  1020 ). This action can be similar to holding down a key on a conventional keyboard. For example, if a finger is held down for a short time at the end of the swipe (e.g., about a second), the swipe symbol can begin repeating at a predetermined interval. A repeat interval of 100-500 ms, and preferably around 200 ms, is suitable, although other intervals could be used. 
     The technique for determining whether a swipe is horizontal or vertical discussed above with respect to block  1013  implicitly assumes that swipes at an angle greater than 45° will be interpreted as vertical and swipes at an angle less than 45° will be interpreted as horizontal swipes. The coordinate system of  FIG. 11A  includes horizontal and vertical axes and separating lines drawn on 45° angles that create eight sectors. The four sectors in which the magnitude of the vertical motion exceeds the magnitude of the horizontal motion are identified with a letter “V,” and the four sectors in which the magnitude of the horizontal motion exceeds the magnitude of the vertical motion are identified with a letter “H.” Thus, the test in block  113  could be replaced with determining whether the tangent of the ratio between the vertical and horizontal motion is greater than 1. If so, the motion is vertical; if not, the motion is horizontal. 
     However, it may be desired to change the angle that is used to discriminate between horizontal and vertical swipes. For example, because of the way a device is held, there may tend to be some vertical motion included with a horizontal swipe because of the way a user&#39;s joints are arranged, etc. As shown in  FIG. 11C , a rightward swipe may include a vertical displacement because of the path traced by a thumb that is also holding the device. As shown in  FIG. 11B , 60° (or any other angle) can also be used to discriminate between horizontal and vertical swipes. In the given example, the tangent of the ratio of vertical displacement of the path to horizontal displacement of the path can be compared to √3 (or any other tangent value corresponding to the desired angle). This idea can also be used to create additional swipes. For example, in addition to the up, down, left, and right swipes, diagonal up-left, diagonal up-right, diagonal down-left, and diagonal down-right swipes can also be created, with ranges of angles (and corresponding tangents thereof) used to discriminate amongst them. 
     An example computer system  1300  that can implement swipe gestures as described above is illustrated in the simplified schematic of  FIG. 13 . The program may be stored in a memory  1305  of the computer system, including solid state memory (RAM, ROM, etc.), hard drive memory, or other suitable memory. CPU  1304  may retrieve and execute the program. CPU  1304  may also receive input through a multi-touch interface  1301  or other input devices not shown. In some embodiments, I/O processor  1303  may perform some level of processing on the inputs before they are passed to CPU  1304 . CPU  1304  may also convey information to the user through display  1302 . Again, in some embodiments, an I/O processor  1303  may perform some or all of the graphics manipulations to offload computation from CPU  1304 . Also, in some embodiments, multi-touch interface  1301  and display  1302  may be integrated into a single device, e.g., a touch screen. 
     The computer system may be any of a variety of types illustrated in  FIG. 12 , including desktop computers  1201 , notebook computers  1202 , tablet computers  1203 , handheld computers  1204 , personal digital assistants  1205 , media players  1206 , mobile telephones  1207 , and the like. Additionally, the computer may be a combination of these types, for example, a device that is a combination of a personal digital assistant, media player, and mobile telephone. 
     Further modifications and alternative embodiments will be apparent to those skilled in the art in view of this disclosure. For example, although the foregoing description has discussed touch screen applications in handheld devices, the techniques described are equally applicable to touch pads or other touch-sensitive devices and larger form factor devices. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the manner of carrying out the invention. It is to be understood that the forms of the invention herein shown and described are to be taken as exemplary embodiments. Various modifications may be made without departing from the scope of the invention.