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Diffstat (limited to 'gfx/layers/apz/src/GestureEventListener.h')
| -rw-r--r-- | gfx/layers/apz/src/GestureEventListener.h | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/gfx/layers/apz/src/GestureEventListener.h b/gfx/layers/apz/src/GestureEventListener.h new file mode 100644 index 0000000000..aa51889fdd --- /dev/null +++ b/gfx/layers/apz/src/GestureEventListener.h @@ -0,0 +1,285 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef mozilla_layers_GestureEventListener_h +#define mozilla_layers_GestureEventListener_h + +#include "InputData.h" // for MultiTouchInput, etc +#include "Units.h" +#include "mozilla/EventForwards.h" // for nsEventStatus +#include "mozilla/RefPtr.h" // for RefPtr +#include "nsISupportsImpl.h" +#include "nsTArray.h" // for nsTArray + +namespace mozilla { + +class CancelableRunnable; + +namespace layers { + +class AsyncPanZoomController; + +/** + * Platform-non-specific, generalized gesture event listener. This class + * intercepts all touches events on their way to AsyncPanZoomController and + * determines whether or not they are part of a gesture. + * + * For example, seeing that two fingers are on the screen means that the user + * wants to do a pinch gesture, so we don't forward the touches along to + * AsyncPanZoomController since it will think that they are just trying to pan + * the screen. Instead, we generate a PinchGestureInput and send that. If the + * touch event is not part of a gesture, we just return nsEventStatus_eIgnore + * and AsyncPanZoomController is expected to handle it. + */ +class GestureEventListener final { + public: + NS_INLINE_DECL_THREADSAFE_REFCOUNTING(GestureEventListener) + + explicit GestureEventListener( + AsyncPanZoomController* aAsyncPanZoomController); + + // -------------------------------------------------------------------------- + // These methods must only be called on the controller/UI thread. + // + + /** + * General input handler for a touch event. If the touch event is not a part + * of a gesture, then we pass it along to AsyncPanZoomController. Otherwise, + * it gets consumed here and never forwarded along. + */ + nsEventStatus HandleInputEvent(const MultiTouchInput& aEvent); + + /** + * Returns the identifier of the touch in the last touch event processed by + * this GestureEventListener. This should only be called when the last touch + * event contained only one touch. + */ + int32_t GetLastTouchIdentifier() const; + + /** + * Function used to disable long tap gestures. + * + * On slow running tests, drags and touch events can be misinterpreted + * as a long tap. This allows tests to disable long tap gesture detection. + */ + static void SetLongTapEnabled(bool aLongTapEnabled); + static bool IsLongTapEnabled(); + + private: + // Private destructor, to discourage deletion outside of Release(): + ~GestureEventListener(); + + /** + * States of GEL finite-state machine. + */ + enum GestureState { + // This is the initial and final state of any gesture. + // In this state there's no gesture going on, and we don't think we're + // about to enter one. + // Allowed next states: GESTURE_FIRST_SINGLE_TOUCH_DOWN, + // GESTURE_MULTI_TOUCH_DOWN. + GESTURE_NONE, + + // A touch start with a single touch point has just happened. + // After having gotten into this state we start timers for MAX_TAP_TIME and + // StaticPrefs::ui_click_hold_context_menus_delay(). + // Allowed next states: GESTURE_MULTI_TOUCH_DOWN, GESTURE_NONE, + // GESTURE_FIRST_SINGLE_TOUCH_UP, + // GESTURE_LONG_TOUCH_DOWN, + // GESTURE_FIRST_SINGLE_TOUCH_MAX_TAP_DOWN. + GESTURE_FIRST_SINGLE_TOUCH_DOWN, + + // While in GESTURE_FIRST_SINGLE_TOUCH_DOWN state a MAX_TAP_TIME timer got + // triggered. Now we'll trigger either a single tap if a user lifts her + // finger or a long tap if StaticPrefs::ui_click_hold_context_menus_delay() + // happens first. + // Allowed next states: GESTURE_MULTI_TOUCH_DOWN, GESTURE_NONE, + // GESTURE_LONG_TOUCH_DOWN. + GESTURE_FIRST_SINGLE_TOUCH_MAX_TAP_DOWN, + + // A user put her finger down and lifted it up quickly enough. + // After having gotten into this state we clear the timer for MAX_TAP_TIME. + // Allowed next states: GESTURE_SECOND_SINGLE_TOUCH_DOWN, GESTURE_NONE, + // GESTURE_MULTI_TOUCH_DOWN. + GESTURE_FIRST_SINGLE_TOUCH_UP, + + // A user put down her finger again right after a single tap thus the + // gesture can't be a single tap, but rather a double tap. But we're + // still not sure about that until the user lifts her finger again. + // Allowed next states: GESTURE_MULTI_TOUCH_DOWN, GESTURE_ONE_TOUCH_PINCH, + // GESTURE_NONE. + GESTURE_SECOND_SINGLE_TOUCH_DOWN, + + // A long touch has happened, but the user still keeps her finger down. + // We'll trigger a "long tap up" event when the finger is up. + // Allowed next states: GESTURE_NONE, GESTURE_MULTI_TOUCH_DOWN. + GESTURE_LONG_TOUCH_DOWN, + + // We have detected that two or more fingers are on the screen, but there + // hasn't been enough movement yet to make us start actually zooming the + // screen. + // Allowed next states: GESTURE_PINCH, GESTURE_NONE + GESTURE_MULTI_TOUCH_DOWN, + + // There are two or more fingers on the screen, and the user has already + // pinched enough for us to start zooming the screen. + // Allowed next states: GESTURE_NONE + GESTURE_PINCH, + + // The user has double tapped, but not lifted her finger, and moved her + // finger more than PINCH_START_THRESHOLD. + // Allowed next states: GESTURE_NONE. + GESTURE_ONE_TOUCH_PINCH + }; + + /** + * These HandleInput* functions comprise input alphabet of the GEL + * finite-state machine triggering state transitions. + */ + nsEventStatus HandleInputTouchSingleStart(); + nsEventStatus HandleInputTouchMultiStart(); + nsEventStatus HandleInputTouchEnd(); + nsEventStatus HandleInputTouchMove(); + nsEventStatus HandleInputTouchCancel(); + void HandleInputTimeoutLongTap(); + void HandleInputTimeoutMaxTap(bool aDuringFastFling); + + void EnterFirstSingleTouchDown(); + + void TriggerSingleTapConfirmedEvent(); + + bool MoveDistanceExceeds(ScreenCoord aThreshold) const; + bool MoveDistanceIsLarge() const; + bool SecondTapIsFar() const; + + /** + * Returns current vertical span, counting from the where the gesture first + * began (after a brief delay detecting the gesture from first touch). + */ + ScreenCoord GetYSpanFromGestureStartPoint(); + + /** + * Do actual state transition and reset substates. + */ + void SetState(GestureState aState); + + RefPtr<AsyncPanZoomController> mAsyncPanZoomController; + + /** + * Array containing all active touches. When a touch happens it, gets added to + * this array, even if we choose not to handle it. When it ends, we remove it. + * We need to maintain this array in order to detect the end of the + * "multitouch" states because touch start events contain all current touches, + * but touch end events contain only those touches that have gone. + */ + nsTArray<SingleTouchData> mTouches; + + /** + * Current state we're dealing with. + */ + GestureState mState; + + /** + * Total change in span since we detected a pinch gesture. Only used when we + * are in the |GESTURE_WAITING_PINCH| state and need to know how far zoomed + * out we are compared to our original pinch span. Note that this does _not_ + * continue to be updated once we jump into the |GESTURE_PINCH| state. + */ + ScreenCoord mSpanChange; + + /** + * Previous span calculated for the purposes of setting inside a + * PinchGestureInput. + */ + ScreenCoord mPreviousSpan; + + /* Properties similar to mSpanChange and mPreviousSpan, but for the focus */ + ScreenCoord mFocusChange; + ScreenPoint mPreviousFocus; + + /** + * Cached copy of the last touch input. + */ + MultiTouchInput mLastTouchInput; + + /** + * Cached copy of the last tap gesture input. + * In the situation when we have a tap followed by a pinch we lose info + * about tap since we keep only last input and to dispatch it correctly + * we save last tap copy into this variable. + * For more info see bug 947892. + */ + MultiTouchInput mLastTapInput; + + /** + * Position of the last touch that exceeds the GetTouchStartTolerance when + * performing a one-touch-pinch gesture; using the mTouchStartPosition is + * slightly inaccurate because by the time the touch position has passed + * the threshold for the gesture, there is already a span that the zoom + * is calculated from, instead of starting at 1.0 when the threshold gets + * passed. + */ + ScreenPoint mOneTouchPinchStartPosition; + + /** + * Position of the last touch starting. This is only valid during an attempt + * to determine if a touch is a tap. If a touch point moves away from + * mTouchStartPosition to the distance greater than + * AsyncPanZoomController::GetTouchStartTolerance() while in + * GESTURE_FIRST_SINGLE_TOUCH_DOWN, GESTURE_FIRST_SINGLE_TOUCH_MAX_TAP_DOWN + * or GESTURE_SECOND_SINGLE_TOUCH_DOWN then we're certain the gesture is + * not tap. + */ + ScreenPoint mTouchStartPosition; + + /** + * We store the window/GeckoView's display offset as well, so we can + * track the user's physical touch movements in absolute display coordinates. + */ + ExternalPoint mTouchStartOffset; + + /** + * Task used to timeout a long tap. This gets posted to the UI thread such + * that it runs a time when a single tap happens. We cache it so that + * we can cancel it if any other touch event happens. + * + * The task is supposed to be non-null if in GESTURE_FIRST_SINGLE_TOUCH_DOWN + * and GESTURE_FIRST_SINGLE_TOUCH_MAX_TAP_DOWN states. + * + * CancelLongTapTimeoutTask: Cancel the mLongTapTimeoutTask and also set + * it to null. + */ + RefPtr<CancelableRunnable> mLongTapTimeoutTask; + void CancelLongTapTimeoutTask(); + void CreateLongTapTimeoutTask(); + + /** + * Task used to timeout a single tap or a double tap. + * + * The task is supposed to be non-null if in GESTURE_FIRST_SINGLE_TOUCH_DOWN, + * GESTURE_FIRST_SINGLE_TOUCH_UP and GESTURE_SECOND_SINGLE_TOUCH_DOWN states. + * + * CancelMaxTapTimeoutTask: Cancel the mMaxTapTimeoutTask and also set + * it to null. + */ + RefPtr<CancelableRunnable> mMaxTapTimeoutTask; + void CancelMaxTapTimeoutTask(); + void CreateMaxTapTimeoutTask(); + + /** + * Tracks whether the single-tap event was already sent to content. This is + * needed because it affects how the double-tap gesture, if detected, is + * handled. The value is only valid in states GESTURE_FIRST_SINGLE_TOUCH_UP + * and GESTURE_SECOND_SINGLE_TOUCH_DOWN; to more easily catch violations it is + * stored in a Maybe which is set to Nothing() at all other times. + */ + Maybe<bool> mSingleTapSent; +}; + +} // namespace layers +} // namespace mozilla + +#endif |