diff options
Diffstat (limited to 'chromium/docs/website/site/developers/design-documents/aura/gesture-recognizer/index.md')
| -rw-r--r-- | chromium/docs/website/site/developers/design-documents/aura/gesture-recognizer/index.md | 191 |
1 files changed, 0 insertions, 191 deletions
diff --git a/chromium/docs/website/site/developers/design-documents/aura/gesture-recognizer/index.md b/chromium/docs/website/site/developers/design-documents/aura/gesture-recognizer/index.md deleted file mode 100644 index bef766bb63d..00000000000 --- a/chromium/docs/website/site/developers/design-documents/aura/gesture-recognizer/index.md +++ /dev/null @@ -1,191 +0,0 @@ ---- -breadcrumbs: -- - /developers - - For Developers -- - /developers/design-documents - - Design Documents -- - /developers/design-documents/aura - - Aura -page_name: gesture-recognizer -title: Gesture Recognizer ---- - -# Gesture Recognizer Overview - -This document describes the process by which Touch Events received by a -WindowEventDispatcher are transformed into Gesture Events. - -[TOC] - -## Touch Events - -* Press -* Move -* Release -* Cancel: fired on preventDefault'ed release, or when we need to - truncate a touch stream (i.e. when something else takes window - capture) - -## Gesture Events - -Gesture Events contain type specific data in their GestureEventDetails object. -See -[here](https://docs.google.com/document/d/1mQFx99xz5jVUHQk2jZTjHPgMjRQd4EUDfdLG0XKOlWI/edit) -for a summary of the typical event sequences. - -* Tap Down - * Fired when the first finger is pressed. -* Show Press - * Fired on a delay after a tap down if no movement has occurred, - or directly before a tap if the finger is released before the - delay is finished. - * Triggers the active state. -* Tap - * Fired after a press followed by a release, within the tap - timeout window. - * Has a "tap_count" field, indicating whether or not this is a - single, double or triple tap. -* Tap Cancel - * Eventually fired after every Tap Down which doesn't result in a - tap. -* Double Tap - * Only fired on Android, where it is used for double tap zooming. -* Tap Unconfirmed - * Only fired on Android. - * Occurs whenever a tap would occur on Aura. - * On Android, tap is fired after a delay, to ensure the current - gesture isn't a double tap. -* Long Press - * Fired on a delay after a tap down, if no movement has occurred. -* Swipe - * Some number of fingers were pressed, and then at least one - finger was released while all fingers were moving in the same - direction. - * Contains the direction the fingers were moving in. -* Scroll Begin - * Contains the offset from the tap down, to hint at the direct the - scroll is likely to be in. -* Scroll Update - * Contains the scroll delta. -* Scroll End - * Fired when a finger is lifted during scroll, without enough - velocity to cause a fling. -* Fling Start - * Fired when a finger is lifted during scroll, with enough - velocity to cause a fling. -* Fling Cancel - * If we're in a fling, stop it. This is synthesized and dispatched - immediately before each tap down event. -* Pinch Begin -* Pinch Update - * Associated scale. -* Pinch End -* Two Finger Tap - * Two fingers were pressed, then one was released, without much - finger movement. -* Begin - * A finger was pressed. You can figure out how many fingers are - down now using event.details.touch_points(). -* End - * A finger was released. You can figure out how many fingers are - down now using event.details.touch_points(). - -## Terminology - -* Touch Lock: - * The association between an existing touch and its target. -* Touch Capture: - * If a window is capturing touches, new touches will be targetted - at the capturing window. -* Touch Id: - * The global id given to each touch. Contiguous starting from 0 - for each display. -* Rail Scroll: - * A scroll which is locked to only move vertically or - horizontally. -* Fling: - * When scrolling, if the user releases their fingers, but the - scroll should continue, this is known as a fling. - -# Finding a Target - -## Possible ways of establishing a target - -1. If a touch is already locked to a target, keep it. -2. If a window is capturing touches, target that window. -3. If it's outside the root window, target the root window. -4. If it's near another touch, use the other touch's target. -5. Otherwise, use whichever window the touch is above. - -In the following images, a filled in circle represents a touch down, and the -outline of a circle represents a position the touch has moved to. The dotted -green line indicates the window that a touch is targeted at. The rounded -rectangle represents a window, and the outer rectangle represents the root -window. - -<table> -<tr> -<td>1. If a touch is already locked to a target, keep it. <img alt="image" src="https://lh6.googleusercontent.com/myjxUQXxaThmV7EUoCfCXkyg0YVCFgdlQKO3gpRdynZ4lSMyJGzLnPdPRDe2qBa_qV6gkKxKn_Ghmv43nVY6SUJr8eb_IOevWjtNvBrCn4OGpm7yo7E" height=214px; width=223px;></td> -<td>2. If a window is capturing touches, target that window. </td> -<td><img alt="image" src="https://lh6.googleusercontent.com/JyqtKa63Qh9yRhlmok8LDLeA2eiKK-CsrKROfmS4SsT7Wign6pkQqMiz0VnPBco5tn3MbGLhe4U--avCCeNB-jSGVUU4YTAJSXkg-ay1KLPrJn6mxwo" height=214px; width=223px;></td> -</tr> -<tr> -<td>3. If it's outside the root window, target the root window.</td> -<td><img alt="image" src="https://lh5.googleusercontent.com/YwO3KZjo5CLMQ-_XNOplU4a9YQtIMi1pLqtOZAcX6RLEnGtJ5D4M0Vxjj83RxPAwd8Hp0-_VCc6DKE9melGnYs1kybpxOB9Xdo-zwCV9-XK_MT-hhpQ" height=214px; width=265px;> </td> -<td>4. If it's near another touch, use the other touch's target. </td> -<td><img alt="image" src="https://lh3.googleusercontent.com/erpsfYRchXsW5q3Al2rSqngixvmYX_q4hjMaSd96Ak1OCQ89jXE6jsdJnF1cFdgNhIH8tIKxYt60o10mqyjeYZ4nx3trlaWhqRkkK61Y61JNmNg6O6I" height=214px; width=222px;></td> -</tr> -<tr> -<td>5. Otherwise, use whichever window the touch is above. <img alt="image" src="https://lh4.googleusercontent.com/rc5RUdxi_QKrsAYU_DF1v9sVmZyAbYzFQDTUrCsiKVshb4dB7338BwT-bPDpUH1btF5UrrzlzkfgCA8I7qXDes0njRZARTW1qC-_fM9vP5R6E7F1LrQ" height=214px; width=223px;></td> -</tr> -</table> - -## Complications - -### preventDefault’ed Release - -When Javascript calls preventDefault on a touch release, we need to make sure -that no gesture events are created, but we also need to ensure that the -GestureRecognizer knows that the associated finger isn’t down any more. To -accomplish this, we turn the touch release into a touch cancel event. - -### Touch Capture - -When a touch capture occurs, all touches on windows other than the window -gaining capture need to be ignored until they are released. To do this, we fire -a touch cancel for each of these touches. - -# Generating Gesture Events - -Each touch-id has an associated window (See -GestureRecognizerImpl::touch_id_target_), and each window has an associated -GestureProviderAura. - -GestureProviderAura contains a FilteredGestureProvider, which is responsible for -performing gesture detection on both Android and Aura. - -# Where To Start - -[GestureRecognizerImpl](https://code.google.com/p/chromium/codesearch#chromium/src/ui/events/gestures/gesture_recognizer_impl.h&sq=package:chromium) - -* Responsible for mapping from touches to windows, and hosts the - [GestureProviderAura](https://code.google.com/p/chromium/codesearch#chromium/src/ui/events/gestures/gesture_provider_aura.h&q=GestureProviderAura&sq=package:chromium&l=26) - objects. - -[GestureDetector](https://code.google.com/p/chromium/codesearch#chromium/src/ui/events/gesture_detection/gesture_detector.cc&q=gesture_dete&sq=package:chromium&l=1), -[ScaleGestureDetector](https://code.google.com/p/chromium/codesearch#chromium/src/ui/events/gesture_detection/scale_gesture_detector.cc&sq=package:chromium) - -* Take in touches, and fire callbacks for each gesture. - -[GestureProvider](https://code.google.com/p/chromium/codesearch#chromium/src/ui/events/gesture_detection/gesture_provider.h&q=GestureProvider) - -* Hosts the - [GestureDetector](https://code.google.com/p/chromium/codesearch#chromium/src/ui/events/gesture_detection/gesture_detector.cc&q=gesture_dete&sq=package:chromium&l=1) - and - [ScaleGestureDetector](https://code.google.com/p/chromium/codesearch#chromium/src/ui/events/gesture_detection/scale_gesture_detector.cc&sq=package:chromium). -* Constructs - [GestureEventData](https://code.google.com/p/chromium/codesearch#chromium/src/ui/events/gesture_detection/gesture_event_data.h&q=GestureEventData&sq=package:chromium&l=17) - objects, which are turned into - [GestureEvent](https://code.google.com/p/chromium/codesearch#chromium/src/ui/events/event.h&q=GestureEvent&sq=package:chromium&l=654) - objects in - [GestureProviderAura](https://code.google.com/p/chromium/codesearch#chromium/src/ui/events/gestures/gesture_provider_aura.h&q=GestureProviderAura&sq=package:chromium&l=26).
\ No newline at end of file |