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Diffstat (limited to 'gfx/layers/apz/src/AsyncPanZoomController.h')
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diff --git a/gfx/layers/apz/src/AsyncPanZoomController.h b/gfx/layers/apz/src/AsyncPanZoomController.h new file mode 100644 index 000000000..36f2f308c --- /dev/null +++ b/gfx/layers/apz/src/AsyncPanZoomController.h @@ -0,0 +1,1224 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set sw=2 ts=8 et 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_AsyncPanZoomController_h +#define mozilla_layers_AsyncPanZoomController_h + +#include "CrossProcessMutex.h" +#include "mozilla/layers/GeckoContentController.h" +#include "mozilla/layers/APZCTreeManager.h" +#include "mozilla/layers/AsyncPanZoomAnimation.h" +#include "mozilla/Attributes.h" +#include "mozilla/EventForwards.h" +#include "mozilla/Monitor.h" +#include "mozilla/ReentrantMonitor.h" +#include "mozilla/RefPtr.h" +#include "mozilla/UniquePtr.h" +#include "mozilla/Atomics.h" +#include "InputData.h" +#include "Axis.h" +#include "InputQueue.h" +#include "APZUtils.h" +#include "Layers.h" // for Layer::ScrollDirection +#include "LayersTypes.h" +#include "mozilla/gfx/Matrix.h" +#include "nsIScrollableFrame.h" +#include "nsRegion.h" +#include "nsTArray.h" +#include "PotentialCheckerboardDurationTracker.h" + +#include "base/message_loop.h" + +namespace mozilla { + +namespace ipc { + +class SharedMemoryBasic; + +} // namespace ipc + +namespace layers { + +class AsyncDragMetrics; +struct ScrollableLayerGuid; +class CompositorController; +class MetricsSharingController; +class GestureEventListener; +struct AsyncTransform; +class AsyncPanZoomAnimation; +class AndroidFlingAnimation; +class GenericFlingAnimation; +class InputBlockState; +class TouchBlockState; +class PanGestureBlockState; +class OverscrollHandoffChain; +class StateChangeNotificationBlocker; +class CheckerboardEvent; +class OverscrollEffectBase; +class WidgetOverscrollEffect; +class GenericOverscrollEffect; +class AndroidSpecificState; + +// Base class for grouping platform-specific APZC state variables. +class PlatformSpecificStateBase { +public: + virtual ~PlatformSpecificStateBase() {} + virtual AndroidSpecificState* AsAndroidSpecificState() { return nullptr; } +}; + +/** + * Controller for all panning and zooming logic. Any time a user input is + * detected and it must be processed in some way to affect what the user sees, + * it goes through here. Listens for any input event from InputData and can + * optionally handle WidgetGUIEvent-derived touch events, but this must be done + * on the main thread. Note that this class completely cross-platform. + * + * Input events originate on the UI thread of the platform that this runs on, + * and are then sent to this class. This class processes the event in some way; + * for example, a touch move will usually lead to a panning of content (though + * of course there are exceptions, such as if content preventDefaults the event, + * or if the target frame is not scrollable). The compositor interacts with this + * class by locking it and querying it for the current transform matrix based on + * the panning and zooming logic that was invoked on the UI thread. + * + * Currently, each outer DOM window (i.e. a website in a tab, but not any + * subframes) has its own AsyncPanZoomController. In the future, to support + * asynchronously scrolled subframes, we want to have one AsyncPanZoomController + * per frame. + */ +class AsyncPanZoomController { + NS_INLINE_DECL_THREADSAFE_REFCOUNTING(AsyncPanZoomController) + + typedef mozilla::MonitorAutoLock MonitorAutoLock; + typedef mozilla::gfx::Matrix4x4 Matrix4x4; + +public: + enum GestureBehavior { + // The platform code is responsible for forwarding gesture events here. We + // will not attempt to generate gesture events from MultiTouchInputs. + DEFAULT_GESTURES, + // An instance of GestureEventListener is used to detect gestures. This is + // handled completely internally within this class. + USE_GESTURE_DETECTOR + }; + + /** + * Constant describing the tolerance in distance we use, multiplied by the + * device DPI, before we start panning the screen. This is to prevent us from + * accidentally processing taps as touch moves, and from very short/accidental + * touches moving the screen. + * Note: It's an abuse of the 'Coord' class to use it to represent a 2D + * distance, but it's the closest thing we currently have. + */ + static ScreenCoord GetTouchStartTolerance(); + + AsyncPanZoomController(uint64_t aLayersId, + APZCTreeManager* aTreeManager, + const RefPtr<InputQueue>& aInputQueue, + GeckoContentController* aController, + GestureBehavior aGestures = DEFAULT_GESTURES); + + // -------------------------------------------------------------------------- + // These methods must only be called on the gecko thread. + // + + /** + * Read the various prefs and do any global initialization for all APZC instances. + * This must be run on the gecko thread before any APZC instances are actually + * used for anything meaningful. + */ + static void InitializeGlobalState(); + + // -------------------------------------------------------------------------- + // These methods must only be called on the controller/UI thread. + // + + /** + * Kicks an animation to zoom to a rect. This may be either a zoom out or zoom + * in. The actual animation is done on the compositor thread after being set + * up. + */ + void ZoomToRect(CSSRect aRect, const uint32_t aFlags); + + /** + * Updates any zoom constraints contained in the <meta name="viewport"> tag. + */ + void UpdateZoomConstraints(const ZoomConstraints& aConstraints); + + /** + * Return the zoom constraints last set for this APZC (in the constructor + * or in UpdateZoomConstraints()). + */ + ZoomConstraints GetZoomConstraints() const; + + /** + * Schedules a runnable to run on the controller/UI thread at some time + * in the future. + */ + void PostDelayedTask(already_AddRefed<Runnable> aTask, int aDelayMs); + + // -------------------------------------------------------------------------- + // These methods must only be called on the compositor thread. + // + + /** + * Advances any animations currently running to the given timestamp. + * This may be called multiple times with the same timestamp. + * + * The return value indicates whether or not any currently running animation + * should continue. If true, the compositor should schedule another composite. + */ + bool AdvanceAnimations(const TimeStamp& aSampleTime); + + bool UpdateAnimation(const TimeStamp& aSampleTime, + nsTArray<RefPtr<Runnable>>* aOutDeferredTasks); + + /** + * A shadow layer update has arrived. |aScrollMetdata| is the new ScrollMetadata + * for the container layer corresponding to this APZC. + * |aIsFirstPaint| is a flag passed from the shadow + * layers code indicating that the scroll metadata being sent with this call are + * the initial metadata and the initial paint of the frame has just happened. + */ + void NotifyLayersUpdated(const ScrollMetadata& aScrollMetadata, bool aIsFirstPaint, + bool aThisLayerTreeUpdated); + + /** + * The platform implementation must set the compositor controller so that we can + * request composites. + */ + void SetCompositorController(CompositorController* aCompositorController); + + /** + * If we need to share the frame metrics with some other thread, this controller + * needs to be set and provides relevant information/APIs. + */ + void SetMetricsSharingController(MetricsSharingController* aMetricsSharingController); + + // -------------------------------------------------------------------------- + // These methods can be called from any thread. + // + + /** + * Shut down the controller/UI thread state and prepare to be + * deleted (which may happen from any thread). + */ + void Destroy(); + + /** + * Returns true if Destroy() has already been called on this APZC instance. + */ + bool IsDestroyed() const; + + /** + * Returns the transform to take something from the coordinate space of the + * last thing we know gecko painted, to the coordinate space of the last thing + * we asked gecko to paint. In cases where that last request has not yet been + * processed, this is needed to transform input events properly into a space + * gecko will understand. + */ + Matrix4x4 GetTransformToLastDispatchedPaint() const; + + /** + * Returns the number of CSS pixels of checkerboard according to the metrics + * in this APZC. + */ + uint32_t GetCheckerboardMagnitude() const; + + /** + * Report the number of CSSPixel-milliseconds of checkerboard to telemetry. + */ + void ReportCheckerboard(const TimeStamp& aSampleTime); + + /** + * Flush any active checkerboard report that's in progress. This basically + * pretends like any in-progress checkerboard event has terminated, and pushes + * out the report to the checkerboard reporting service and telemetry. If the + * checkerboard event has not really finished, it will start a new event + * on the next composite. + */ + void FlushActiveCheckerboardReport(); + + /** + * Returns whether or not the APZC is currently in a state of checkerboarding. + * This is a simple computation based on the last-painted content and whether + * the async transform has pushed it so far that it doesn't fully contain the + * composition bounds. + */ + bool IsCurrentlyCheckerboarding() const; + + /** + * Recalculates the displayport. Ideally, this should paint an area bigger + * than the composite-to dimensions so that when you scroll down, you don't + * checkerboard immediately. This includes a bunch of logic, including + * algorithms to bias painting in the direction of the velocity. + */ + static const ScreenMargin CalculatePendingDisplayPort( + const FrameMetrics& aFrameMetrics, + const ParentLayerPoint& aVelocity); + + nsEventStatus HandleDragEvent(const MouseInput& aEvent, + const AsyncDragMetrics& aDragMetrics); + + /** + * Handler for events which should not be intercepted by the touch listener. + */ + nsEventStatus HandleInputEvent(const InputData& aEvent, + const ScreenToParentLayerMatrix4x4& aTransformToApzc); + + /** + * Handler for gesture events. + * Currently some gestures are detected in GestureEventListener that calls + * APZC back through this handler in order to avoid recursive calls to + * APZC::HandleInputEvent() which is supposed to do the work for + * ReceiveInputEvent(). + */ + nsEventStatus HandleGestureEvent(const InputData& aEvent); + + /** + * Handler for touch velocity. + * Sometimes the touch move event will have a velocity even though no scrolling + * is occurring such as when the toolbar is being hidden/shown in Fennec. + * This function can be called to have the y axis' velocity queue updated. + */ + void HandleTouchVelocity(uint32_t aTimesampMs, float aSpeedY); + + /** + * Populates the provided object (if non-null) with the scrollable guid of this apzc. + */ + void GetGuid(ScrollableLayerGuid* aGuidOut) const; + + /** + * Returns the scrollable guid of this apzc. + */ + ScrollableLayerGuid GetGuid() const; + + /** + * Returns true if this APZC instance is for the layer identified by the guid. + */ + bool Matches(const ScrollableLayerGuid& aGuid); + + /** + * Returns true if the tree manager of this APZC is the same as the one + * passed in. + */ + bool HasTreeManager(const APZCTreeManager* aTreeManager) const; + + void StartAnimation(AsyncPanZoomAnimation* aAnimation); + + /** + * Cancels any currently running animation. + * aFlags is a bit-field to provide specifics of how to cancel the animation. + * See CancelAnimationFlags. + */ + void CancelAnimation(CancelAnimationFlags aFlags = Default); + + /** + * Adjusts the scroll position to compensate for a shift in the surface, such + * that the content appears to remain visually in the same position. i.e. if + * the surface moves up by 10 screenpixels, the scroll position should also + * move up by 10 pixels so that what used to be at the top of the surface is + * now 10 pixels down the surface. + */ + void AdjustScrollForSurfaceShift(const ScreenPoint& aShift); + + /** + * Clear any overscroll on this APZC. + */ + void ClearOverscroll(); + + /** + * Returns whether this APZC is for an element marked with the 'scrollgrab' + * attribute. + */ + bool HasScrollgrab() const { return mScrollMetadata.GetHasScrollgrab(); } + + /** + * Returns whether this APZC has room to be panned (in any direction). + */ + bool IsPannable() const; + + /** + * Returns true if the APZC has been flung with a velocity greater than the + * stop-on-tap fling velocity threshold (which is pref-controlled). + */ + bool IsFlingingFast() const; + + /** + * Returns the identifier of the touch in the last touch event processed by + * this APZC. This should only be called when the last touch event contained + * only one touch. + */ + int32_t GetLastTouchIdentifier() const; + + /** + * Returns the matrix that transforms points from global screen space into + * this APZC's ParentLayer space. + * To respect the lock ordering, mMonitor must NOT be held when calling + * this function (since this function acquires the tree lock). + */ + ScreenToParentLayerMatrix4x4 GetTransformToThis() const; + + /** + * Convert the vector |aVector|, rooted at the point |aAnchor|, from + * this APZC's ParentLayer coordinates into screen coordinates. + * The anchor is necessary because with 3D tranforms, the location of the + * vector can affect the result of the transform. + * To respect the lock ordering, mMonitor must NOT be held when calling + * this function (since this function acquires the tree lock). + */ + ScreenPoint ToScreenCoordinates(const ParentLayerPoint& aVector, + const ParentLayerPoint& aAnchor) const; + + /** + * Convert the vector |aVector|, rooted at the point |aAnchor|, from + * screen coordinates into this APZC's ParentLayer coordinates. + * The anchor is necessary because with 3D tranforms, the location of the + * vector can affect the result of the transform. + * To respect the lock ordering, mMonitor must NOT be held when calling + * this function (since this function acquires the tree lock). + */ + ParentLayerPoint ToParentLayerCoordinates(const ScreenPoint& aVector, + const ScreenPoint& aAnchor) const; + + // Return whether or not a wheel event will be able to scroll in either + // direction. + bool CanScroll(const InputData& aEvent) const; + + // Return whether or not a scroll delta will be able to scroll in either + // direction. + bool CanScrollWithWheel(const ParentLayerPoint& aDelta) const; + + // Return whether or not there is room to scroll this APZC + // in the given direction. + bool CanScroll(Layer::ScrollDirection aDirection) const; + + void NotifyMozMouseScrollEvent(const nsString& aString) const; + +protected: + // Protected destructor, to discourage deletion outside of Release(): + virtual ~AsyncPanZoomController(); + + // Returns the cached current frame time. + TimeStamp GetFrameTime() const; + + /** + * Helper method for touches beginning. Sets everything up for panning and any + * multitouch gestures. + */ + nsEventStatus OnTouchStart(const MultiTouchInput& aEvent); + + /** + * Helper method for touches moving. Does any transforms needed when panning. + */ + nsEventStatus OnTouchMove(const MultiTouchInput& aEvent); + + /** + * Helper method for touches ending. Redraws the screen if necessary and does + * any cleanup after a touch has ended. + */ + nsEventStatus OnTouchEnd(const MultiTouchInput& aEvent); + + /** + * Helper method for touches being cancelled. Treated roughly the same as a + * touch ending (OnTouchEnd()). + */ + nsEventStatus OnTouchCancel(const MultiTouchInput& aEvent); + + /** + * Helper method for scales beginning. Distinct from the OnTouch* handlers in + * that this implies some outside implementation has determined that the user + * is pinching. + */ + nsEventStatus OnScaleBegin(const PinchGestureInput& aEvent); + + /** + * Helper method for scaling. As the user moves their fingers when pinching, + * this changes the scale of the page. + */ + nsEventStatus OnScale(const PinchGestureInput& aEvent); + + /** + * Helper method for scales ending. Redraws the screen if necessary and does + * any cleanup after a scale has ended. + */ + nsEventStatus OnScaleEnd(const PinchGestureInput& aEvent); + + /** + * Helper methods for handling pan events. + */ + nsEventStatus OnPanMayBegin(const PanGestureInput& aEvent); + nsEventStatus OnPanCancelled(const PanGestureInput& aEvent); + nsEventStatus OnPanBegin(const PanGestureInput& aEvent); + nsEventStatus OnPan(const PanGestureInput& aEvent, bool aFingersOnTouchpad); + nsEventStatus OnPanEnd(const PanGestureInput& aEvent); + nsEventStatus OnPanMomentumStart(const PanGestureInput& aEvent); + nsEventStatus OnPanMomentumEnd(const PanGestureInput& aEvent); + + /** + * Helper methods for handling scroll wheel events. + */ + nsEventStatus OnScrollWheel(const ScrollWheelInput& aEvent); + + ParentLayerPoint GetScrollWheelDelta(const ScrollWheelInput& aEvent) const; + + /** + * Helper methods for long press gestures. + */ + nsEventStatus OnLongPress(const TapGestureInput& aEvent); + nsEventStatus OnLongPressUp(const TapGestureInput& aEvent); + + /** + * Helper method for single tap gestures. + */ + nsEventStatus OnSingleTapUp(const TapGestureInput& aEvent); + + /** + * Helper method for a single tap confirmed. + */ + nsEventStatus OnSingleTapConfirmed(const TapGestureInput& aEvent); + + /** + * Helper method for double taps. + */ + nsEventStatus OnDoubleTap(const TapGestureInput& aEvent); + + /** + * Helper method for double taps where the double-tap gesture is disabled. + */ + nsEventStatus OnSecondTap(const TapGestureInput& aEvent); + + /** + * Helper method to cancel any gesture currently going to Gecko. Used + * primarily when a user taps the screen over some clickable content but then + * pans down instead of letting go (i.e. to cancel a previous touch so that a + * new one can properly take effect. + */ + nsEventStatus OnCancelTap(const TapGestureInput& aEvent); + + /** + * Scrolls the viewport by an X,Y offset. + */ + void ScrollBy(const CSSPoint& aOffset); + + /** + * Scales the viewport by an amount (note that it multiplies this scale in to + * the current scale, it doesn't set it to |aScale|). Also considers a focus + * point so that the page zooms inward/outward from that point. + */ + void ScaleWithFocus(float aScale, + const CSSPoint& aFocus); + + /** + * Schedules a composite on the compositor thread. + */ + void ScheduleComposite(); + + /** + * Schedules a composite, and if enough time has elapsed since the last + * paint, a paint. + */ + void ScheduleCompositeAndMaybeRepaint(); + + /** + * Gets the displacement of the current touch since it began. That is, it is + * the distance between the current position and the initial position of the + * current touch (this only makes sense if a touch is currently happening and + * OnTouchMove() or the equivalent for pan gestures is being invoked). + * Note: It's an abuse of the 'Coord' class to use it to represent a 2D + * distance, but it's the closest thing we currently have. + */ + ScreenCoord PanDistance() const; + + /** + * Gets the start point of the current touch. + * Like PanDistance(), this only makes sense if a touch is currently + * happening and OnTouchMove() or the equivalent for pan gestures is + * being invoked. + */ + ParentLayerPoint PanStart() const; + + /** + * Gets a vector of the velocities of each axis. + */ + const ParentLayerPoint GetVelocityVector() const; + + /** + * Sets the velocities of each axis. + */ + void SetVelocityVector(const ParentLayerPoint& aVelocityVector); + + /** + * Gets the first touch point from a MultiTouchInput. This gets only + * the first one and assumes the rest are either missing or not relevant. + */ + ParentLayerPoint GetFirstTouchPoint(const MultiTouchInput& aEvent); + + /** + * Sets the panning state basing on the pan direction angle and current touch-action value. + */ + void HandlePanningWithTouchAction(double angle); + + /** + * Sets the panning state ignoring the touch action value. + */ + void HandlePanning(double angle); + + /** + * Update the panning state and axis locks. + */ + void HandlePanningUpdate(const ScreenPoint& aDelta); + + /** + * Sets up anything needed for panning. This takes us out of the "TOUCHING" + * state and starts actually panning us. + */ + nsEventStatus StartPanning(const MultiTouchInput& aStartPoint); + + /** + * Wrapper for Axis::UpdateWithTouchAtDevicePoint(). Calls this function for + * both axes and factors in the time delta from the last update. + */ + void UpdateWithTouchAtDevicePoint(const MultiTouchInput& aEvent); + + /** + * Does any panning required due to a new touch event. + */ + void TrackTouch(const MultiTouchInput& aEvent); + + /** + * Utility function to send updated FrameMetrics to Gecko so that it can paint + * the displayport area. Calls into GeckoContentController to do the actual + * work. This call will use the current metrics. If this function is called + * from a non-main thread, it will redispatch itself to the main thread, and + * use the latest metrics during the redispatch. + */ + void RequestContentRepaint(bool aUserAction = true); + + /** + * Send the provided metrics to Gecko to trigger a repaint. This function + * may filter duplicate calls with the same metrics. This function must be + * called on the main thread. + */ + void RequestContentRepaint(const FrameMetrics& aFrameMetrics, + const ParentLayerPoint& aVelocity); + + /** + * Gets the current frame metrics. This is *not* the Gecko copy stored in the + * layers code. + */ + const FrameMetrics& GetFrameMetrics() const; + + /** + * Gets the pointer to the apzc tree manager. All the access to tree manager + * should be made via this method and not via private variable since this method + * ensures that no lock is set. + */ + APZCTreeManager* GetApzcTreeManager() const; + + /** + * Convert ScreenPoint relative to the screen to LayoutDevicePoint relative + * to the parent document. This excludes the transient compositor transform. + * NOTE: This must be converted to LayoutDevicePoint relative to the child + * document before sending over IPC to a child process. + */ + bool ConvertToGecko(const ScreenIntPoint& aPoint, LayoutDevicePoint* aOut); + + enum AxisLockMode { + FREE, /* No locking at all */ + STANDARD, /* Default axis locking mode that remains locked until pan ends*/ + STICKY, /* Allow lock to be broken, with hysteresis */ + }; + + static AxisLockMode GetAxisLockMode(); + + // Helper function for OnSingleTapUp(), OnSingleTapConfirmed(), and + // OnLongPressUp(). + nsEventStatus GenerateSingleTap(GeckoContentController::TapType aType, + const ScreenIntPoint& aPoint, + mozilla::Modifiers aModifiers); + + // Common processing at the end of a touch block. + void OnTouchEndOrCancel(); + + uint64_t mLayersId; + RefPtr<CompositorController> mCompositorController; + RefPtr<MetricsSharingController> mMetricsSharingController; + + /* Access to the following two fields is protected by the mRefPtrMonitor, + since they are accessed on the UI thread but can be cleared on the + compositor thread. */ + RefPtr<GeckoContentController> mGeckoContentController; + RefPtr<GestureEventListener> mGestureEventListener; + mutable Monitor mRefPtrMonitor; + + // This is a raw pointer to avoid introducing a reference cycle between + // AsyncPanZoomController and APZCTreeManager. Since these objects don't + // live on the main thread, we can't use the cycle collector with them. + // The APZCTreeManager owns the lifetime of the APZCs, so nulling this + // pointer out in Destroy() will prevent accessing deleted memory. + Atomic<APZCTreeManager*> mTreeManager; + + /* Utility functions that return a addrefed pointer to the corresponding fields. */ + already_AddRefed<GeckoContentController> GetGeckoContentController() const; + already_AddRefed<GestureEventListener> GetGestureEventListener() const; + + PlatformSpecificStateBase* GetPlatformSpecificState(); + +protected: + // Both |mFrameMetrics| and |mLastContentPaintMetrics| are protected by the + // monitor. Do not read from or modify either of them without locking. + ScrollMetadata mScrollMetadata; + FrameMetrics& mFrameMetrics; // for convenience, refers to mScrollMetadata.mMetrics + + // Protects |mFrameMetrics|, |mLastContentPaintMetrics|, and |mState|. + // Before manipulating |mFrameMetrics| or |mLastContentPaintMetrics|, the + // monitor should be held. When setting |mState|, either the SetState() + // function can be used, or the monitor can be held and then |mState| updated. + // IMPORTANT: See the note about lock ordering at the top of APZCTreeManager.h. + // This is mutable to allow entering it from 'const' methods; doing otherwise + // would significantly limit what methods could be 'const'. + mutable ReentrantMonitor mMonitor; + +private: + // Metadata of the container layer corresponding to this APZC. This is + // stored here so that it is accessible from the UI/controller thread. + // These are the metrics at last content paint, the most recent + // values we were notified of in NotifyLayersUpdate(). Since it represents + // the Gecko state, it should be used as a basis for untransformation when + // sending messages back to Gecko. + ScrollMetadata mLastContentPaintMetadata; + FrameMetrics& mLastContentPaintMetrics; // for convenience, refers to mLastContentPaintMetadata.mMetrics + // The last metrics used for a content repaint request. + FrameMetrics mLastPaintRequestMetrics; + // The metrics that we expect content to have. This is updated when we + // request a content repaint, and when we receive a shadow layers update. + // This allows us to transform events into Gecko's coordinate space. + FrameMetrics mExpectedGeckoMetrics; + + AxisX mX; + AxisY mY; + + // This flag is set to true when we are in a axis-locked pan as a result of + // the touch-action CSS property. + bool mPanDirRestricted; + + // Most up-to-date constraints on zooming. These should always be reasonable + // values; for example, allowing a min zoom of 0.0 can cause very bad things + // to happen. + ZoomConstraints mZoomConstraints; + + // The last time the compositor has sampled the content transform for this + // frame. + TimeStamp mLastSampleTime; + + // The last sample time at which we submitted a checkerboarding report. + TimeStamp mLastCheckerboardReport; + + // Stores the previous focus point if there is a pinch gesture happening. Used + // to allow panning by moving multiple fingers (thus moving the focus point). + ParentLayerPoint mLastZoomFocus; + + RefPtr<AsyncPanZoomAnimation> mAnimation; + + UniquePtr<OverscrollEffectBase> mOverscrollEffect; + + // Groups state variables that are specific to a platform. + // Initialized on first use. + UniquePtr<PlatformSpecificStateBase> mPlatformSpecificState; + + friend class Axis; + + + /* =================================================================== + * The functions and members in this section are used to expose + * the current async transform state to callers. + */ +public: + /** + * Allows callers to specify which type of async transform they want: + * NORMAL provides the actual async transforms of the APZC, whereas + * RESPECT_FORCE_DISABLE will provide empty async transforms if and only if + * the metrics has the mForceDisableApz flag set. In general the latter should + * only be used by call sites that are applying the transform to update + * a layer's position. + */ + enum AsyncMode { + NORMAL, + RESPECT_FORCE_DISABLE, + }; + + /** + * Query the transforms that should be applied to the layer corresponding + * to this APZC due to asynchronous panning and zooming. + * This function returns the async transform via the |aOutTransform| + * out parameter. + */ + ParentLayerPoint GetCurrentAsyncScrollOffset(AsyncMode aMode) const; + + /** + * Return a visual effect that reflects this apzc's + * overscrolled state, if any. + */ + AsyncTransformComponentMatrix GetOverscrollTransform(AsyncMode aMode) const; + + /** + * Returns the incremental transformation corresponding to the async pan/zoom + * in progress. That is, when this transform is multiplied with the layer's + * existing transform, it will make the layer appear with the desired pan/zoom + * amount. + */ + AsyncTransform GetCurrentAsyncTransform(AsyncMode aMode) const; + + /** + * Returns the same transform as GetCurrentAsyncTransform(), but includes + * any transform due to axis over-scroll. + */ + AsyncTransformComponentMatrix GetCurrentAsyncTransformWithOverscroll(AsyncMode aMode) const; + + + /* =================================================================== + * The functions and members in this section are used to manage + * the state that tracks what this APZC is doing with the input events. + */ +protected: + enum PanZoomState { + NOTHING, /* no touch-start events received */ + FLING, /* all touches removed, but we're still scrolling page */ + TOUCHING, /* one touch-start event received */ + + PANNING, /* panning the frame */ + PANNING_LOCKED_X, /* touch-start followed by move (i.e. panning with axis lock) X axis */ + PANNING_LOCKED_Y, /* as above for Y axis */ + + PAN_MOMENTUM, /* like PANNING, but controlled by momentum PanGestureInput events */ + + PINCHING, /* nth touch-start, where n > 1. this mode allows pan and zoom */ + ANIMATING_ZOOM, /* animated zoom to a new rect */ + OVERSCROLL_ANIMATION, /* Spring-based animation used to relieve overscroll once + the finger is lifted. */ + SMOOTH_SCROLL, /* Smooth scrolling to destination. Used by + CSSOM-View smooth scroll-behavior */ + WHEEL_SCROLL /* Smooth scrolling to a destination for a wheel event. */ + }; + + // This is in theory protected by |mMonitor|; that is, it should be held whenever + // this is updated. In practice though... see bug 897017. + PanZoomState mState; + +private: + friend class StateChangeNotificationBlocker; + /** + * A counter of how many StateChangeNotificationBlockers are active. + * A non-zero count will prevent state change notifications from + * being dispatched. Only code that holds mMonitor should touch this. + */ + int mNotificationBlockers; + + /** + * Helper to set the current state. Holds the monitor before actually setting + * it and fires content controller events based on state changes. Always set + * the state using this call, do not set it directly. + */ + void SetState(PanZoomState aState); + /** + * Fire content controller notifications about state changes, assuming no + * StateChangeNotificationBlocker has been activated. + */ + void DispatchStateChangeNotification(PanZoomState aOldState, PanZoomState aNewState); + /** + * Internal helpers for checking general state of this apzc. + */ + static bool IsTransformingState(PanZoomState aState); + + /* =================================================================== + * The functions and members in this section are used to manage + * blocks of touch events and the state needed to deal with content + * listeners. + */ +public: + /** + * Flush a repaint request if one is needed, without throttling it with the + * paint throttler. + */ + void FlushRepaintForNewInputBlock(); + + /** + * Given the number of touch points in an input event and touch block they + * belong to, check if the event can result in a panning/zooming behavior. + * This is primarily used to figure out when to dispatch the pointercancel + * event for the pointer events spec. + */ + bool ArePointerEventsConsumable(TouchBlockState* aBlock, uint32_t aTouchPoints); + + /** + * Clear internal state relating to touch input handling. + */ + void ResetTouchInputState(); + + /** + * Gets a ref to the input queue that is shared across the entire tree manager. + */ + const RefPtr<InputQueue>& GetInputQueue() const; + +private: + void CancelAnimationAndGestureState(); + + RefPtr<InputQueue> mInputQueue; + CancelableBlockState* GetCurrentInputBlock() const; + TouchBlockState* GetCurrentTouchBlock() const; + bool HasReadyTouchBlock() const; + + PanGestureBlockState* GetCurrentPanGestureBlock() const; + +private: + /* =================================================================== + * The functions and members in this section are used to manage + * fling animations, smooth scroll animations, and overscroll + * during a fling or smooth scroll. + */ +public: + /** + * Attempt a fling with the velocity specified in |aHandoffState|. + * If we are not pannable, the fling is handed off to the next APZC in + * the handoff chain via mTreeManager->DispatchFling(). + * Returns true iff. the entire velocity of the fling was consumed by + * this APZC. |aHandoffState.mVelocity| is modified to contain any + * unused, residual velocity. + * |aHandoffState.mIsHandoff| should be true iff. the fling was handed off + * from a previous APZC, and determines whether acceleration is applied + * to the fling. + */ + bool AttemptFling(FlingHandoffState& aHandoffState); + +private: + friend class AndroidFlingAnimation; + friend class GenericFlingAnimation; + friend class OverscrollAnimation; + friend class SmoothScrollAnimation; + friend class WheelScrollAnimation; + + friend class GenericOverscrollEffect; + friend class WidgetOverscrollEffect; + + // The initial velocity of the most recent fling. + ParentLayerPoint mLastFlingVelocity; + // The time at which the most recent fling started. + TimeStamp mLastFlingTime; + // Indicates if the repaint-during-pinch timer is currently set + bool mPinchPaintTimerSet; + + // Deal with overscroll resulting from a fling animation. This is only ever + // called on APZC instances that were actually performing a fling. + // The overscroll is handled by trying to hand the fling off to an APZC + // later in the handoff chain, or if there are no takers, continuing the + // fling and entering an overscrolled state. + void HandleFlingOverscroll(const ParentLayerPoint& aVelocity, + const RefPtr<const OverscrollHandoffChain>& aOverscrollHandoffChain, + const RefPtr<const AsyncPanZoomController>& aScrolledApzc); + + void HandleSmoothScrollOverscroll(const ParentLayerPoint& aVelocity); + + // Helper function used by AttemptFling(). + void AcceptFling(FlingHandoffState& aHandoffState); + + // Start an overscroll animation with the given initial velocity. + void StartOverscrollAnimation(const ParentLayerPoint& aVelocity); + + void SmoothScrollTo(const CSSPoint& aDestination); + + // Returns whether overscroll is allowed during an event. + bool AllowScrollHandoffInCurrentBlock() const; + + // Invoked by the pinch repaint timer. + void DoDelayedRequestContentRepaint(); + + /* =================================================================== + * The functions and members in this section are used to make ancestor chains + * out of APZC instances. These chains can only be walked or manipulated + * while holding the lock in the associated APZCTreeManager instance. + */ +public: + void SetParent(AsyncPanZoomController* aParent) { + mParent = aParent; + } + + AsyncPanZoomController* GetParent() const { + return mParent; + } + + /* Returns true if there is no APZC higher in the tree with the same + * layers id. + */ + bool HasNoParentWithSameLayersId() const { + return !mParent || (mParent->mLayersId != mLayersId); + } + + bool IsRootForLayersId() const { + ReentrantMonitorAutoEnter lock(mMonitor); + return mScrollMetadata.IsLayersIdRoot(); + } + + bool IsRootContent() const { + ReentrantMonitorAutoEnter lock(mMonitor); + return mFrameMetrics.IsRootContent(); + } + +private: + // |mTreeManager| belongs in this section but it's declaration is a bit + // further above due to initialization-order constraints. + + RefPtr<AsyncPanZoomController> mParent; + + + /* =================================================================== + * The functions and members in this section are used for scrolling, + * including handing off scroll to another APZC, and overscrolling. + */ +public: + FrameMetrics::ViewID GetScrollHandoffParentId() const { + return mScrollMetadata.GetScrollParentId(); + } + + /** + * Attempt to scroll in response to a touch-move from |aStartPoint| to + * |aEndPoint|, which are in our (transformed) screen coordinates. + * Due to overscroll handling, there may not actually have been a touch-move + * at these points, but this function will scroll as if there had been. + * If this attempt causes overscroll (i.e. the layer cannot be scrolled + * by the entire amount requested), the overscroll is passed back to the + * tree manager via APZCTreeManager::DispatchScroll(). If the tree manager + * does not find an APZC further in the handoff chain to accept the + * overscroll, and this APZC is pannable, this APZC enters an overscrolled + * state. + * |aOverscrollHandoffChain| and |aOverscrollHandoffChainIndex| are used by + * the tree manager to keep track of which APZC to hand off the overscroll + * to; this function increments the chain and the index and passes it on to + * APZCTreeManager::DispatchScroll() in the event of overscroll. + * Returns true iff. this APZC, or an APZC further down the + * handoff chain, accepted the scroll (possibly entering an overscrolled + * state). If this returns false, the caller APZC knows that it should enter + * an overscrolled state itself if it can. + * aStartPoint and aEndPoint are modified depending on how much of the + * scroll gesture was consumed by APZCs in the handoff chain. + */ + bool AttemptScroll(ParentLayerPoint& aStartPoint, + ParentLayerPoint& aEndPoint, + OverscrollHandoffState& aOverscrollHandoffState); + + void FlushRepaintForOverscrollHandoff(); + + /** + * If overscrolled, start a snap-back animation and return true. + * Otherwise return false. + */ + bool SnapBackIfOverscrolled(); + + /** + * Build the chain of APZCs along which scroll will be handed off when + * this APZC receives input events. + * + * Notes on lifetime and const-correctness: + * - The returned handoff chain is |const|, to indicate that it cannot be + * changed after being built. + * - When passing the chain to a function that uses it without storing it, + * pass it by reference-to-const (as in |const OverscrollHandoffChain&|). + * - When storing the chain, store it by RefPtr-to-const (as in + * |RefPtr<const OverscrollHandoffChain>|). This ensures the chain is + * kept alive. Note that queueing a task that uses the chain as an + * argument constitutes storing, as the task may outlive its queuer. + * - When passing the chain to a function that will store it, pass it as + * |const RefPtr<const OverscrollHandoffChain>&|. This allows the + * function to copy it into the |RefPtr<const OverscrollHandoffChain>| + * that will store it, while avoiding an unnecessary copy (and thus + * AddRef() and Release()) when passing it. + */ + RefPtr<const OverscrollHandoffChain> BuildOverscrollHandoffChain(); + +private: + /** + * A helper function for calling APZCTreeManager::DispatchScroll(). + * Guards against the case where the APZC is being concurrently destroyed + * (and thus mTreeManager is being nulled out). + */ + void CallDispatchScroll(ParentLayerPoint& aStartPoint, + ParentLayerPoint& aEndPoint, + OverscrollHandoffState& aOverscrollHandoffState); + + /** + * A helper function for overscrolling during panning. This is a wrapper + * around OverscrollBy() that also implements restrictions on entering + * overscroll based on the pan angle. + */ + void OverscrollForPanning(ParentLayerPoint& aOverscroll, + const ScreenPoint& aPanDistance); + + /** + * Try to overscroll by 'aOverscroll'. + * If we are pannable on a particular axis, that component of 'aOverscroll' + * is transferred to any existing overscroll. + */ + void OverscrollBy(ParentLayerPoint& aOverscroll); + + + /* =================================================================== + * The functions and members in this section are used to maintain the + * area that this APZC instance is responsible for. This is used when + * hit-testing to see which APZC instance should handle touch events. + */ +public: + void SetAncestorTransform(const Matrix4x4& aTransformToLayer) { + mAncestorTransform = aTransformToLayer; + } + + Matrix4x4 GetAncestorTransform() const { + return mAncestorTransform; + } + + // Returns whether or not this apzc contains the given screen point within + // its composition bounds. + bool Contains(const ScreenIntPoint& aPoint) const; + + bool IsOverscrolled() const { + return mX.IsOverscrolled() || mY.IsOverscrolled(); + } + + bool IsInPanningState() const; + +private: + /* This is the cumulative CSS transform for all the layers from (and including) + * the parent APZC down to (but excluding) this one, and excluding any + * perspective transforms. */ + Matrix4x4 mAncestorTransform; + + + /* =================================================================== + * The functions and members in this section are used for sharing the + * FrameMetrics across processes for the progressive tiling code. + */ +private: + /* Unique id assigned to each APZC. Used with ViewID to uniquely identify + * shared FrameMeterics used in progressive tile painting. */ + const uint32_t mAPZCId; + + RefPtr<ipc::SharedMemoryBasic> mSharedFrameMetricsBuffer; + CrossProcessMutex* mSharedLock; + /** + * Called when ever mFrameMetrics is updated so that if it is being + * shared with the content process the shared FrameMetrics may be updated. + */ + void UpdateSharedCompositorFrameMetrics(); + /** + * Create a shared memory buffer for containing the FrameMetrics and + * a CrossProcessMutex that may be shared with the content process + * for use in progressive tiled update calculations. + */ + void ShareCompositorFrameMetrics(); + + + /* =================================================================== + * The functions and members in this section are used for testing + * and assertion purposes only. + */ +public: + /** + * Set an extra offset for testing async scrolling. + */ + void SetTestAsyncScrollOffset(const CSSPoint& aPoint) + { + mTestAsyncScrollOffset = aPoint; + } + /** + * Set an extra offset for testing async scrolling. + */ + void SetTestAsyncZoom(const LayerToParentLayerScale& aZoom) + { + mTestAsyncZoom = aZoom; + } + + void MarkAsyncTransformAppliedToContent() + { + mAsyncTransformAppliedToContent = true; + } + + bool GetAsyncTransformAppliedToContent() const + { + return mAsyncTransformAppliedToContent; + } + + uint64_t GetLayersId() const + { + return mLayersId; + } + +private: + // Extra offset to add to the async scroll position for testing + CSSPoint mTestAsyncScrollOffset; + // Extra zoom to include in the aync zoom for testing + LayerToParentLayerScale mTestAsyncZoom; + // Flag to track whether or not the APZ transform is not used. This + // flag is recomputed for every composition frame. + bool mAsyncTransformAppliedToContent; + + + /* =================================================================== + * The functions and members in this section are used for checkerboard + * recording. + */ +private: + // Helper function to update the in-progress checkerboard event, if any. + void UpdateCheckerboardEvent(const MutexAutoLock& aProofOfLock, + uint32_t aMagnitude); + + // Mutex protecting mCheckerboardEvent + Mutex mCheckerboardEventLock; + // This is created when this APZC instance is first included as part of a + // composite. If a checkerboard event takes place, this is destroyed at the + // end of the event, and a new one is created on the next composite. + UniquePtr<CheckerboardEvent> mCheckerboardEvent; + // This is used to track the total amount of time that we could reasonably + // be checkerboarding. Combined with other info, this allows us to meaningfully + // say how frequently users actually encounter checkerboarding. + PotentialCheckerboardDurationTracker mPotentialCheckerboardTracker; + + + /* =================================================================== + * The functions in this section are used for CSS scroll snapping. + */ + + // If |aEvent| should trigger scroll snapping, adjust |aDelta| to reflect + // the snapping (that is, make it a delta that will take us to the desired + // snap point). The delta is interpreted as being relative to + // |aStartPosition|, and if a target snap point is found, |aStartPosition| + // is also updated, to the value of the snap point. + // Returns true iff. a target snap point was found. + bool MaybeAdjustDeltaForScrollSnapping(const ScrollWheelInput& aEvent, + ParentLayerPoint& aDelta, + CSSPoint& aStartPosition); + + // Snap to a snap position nearby the current scroll position, if appropriate. + void ScrollSnap(); + + // Snap to a snap position nearby the destination predicted based on the + // current velocity, if appropriate. + void ScrollSnapToDestination(); + + // Snap to a snap position nearby the provided destination, if appropriate. + void ScrollSnapNear(const CSSPoint& aDestination); + + // Find a snap point near |aDestination| that we should snap to. + // Returns the snap point if one was found, or an empty Maybe otherwise. + // |aUnit| affects the snapping behaviour (see ScrollSnapUtils:: + // GetSnapPointForDestination). It should generally be determined by the + // type of event that's triggering the scroll. + Maybe<CSSPoint> FindSnapPointNear(const CSSPoint& aDestination, + nsIScrollableFrame::ScrollUnit aUnit); +}; + +} // namespace layers +} // namespace mozilla + +#endif // mozilla_layers_PanZoomController_h |