/* -*- 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& 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 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 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>* 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 mCompositorController; RefPtr 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 mGeckoContentController; RefPtr 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 mTreeManager; /* Utility functions that return a addrefed pointer to the corresponding fields. */ already_AddRefed GetGeckoContentController() const; already_AddRefed 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 mAnimation; UniquePtr mOverscrollEffect; // Groups state variables that are specific to a platform. // Initialized on first use. UniquePtr 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& GetInputQueue() const; private: void CancelAnimationAndGestureState(); RefPtr 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& aOverscrollHandoffChain, const RefPtr& 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 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|). 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&|. This allows the * function to copy it into the |RefPtr| * that will store it, while avoiding an unnecessary copy (and thus * AddRef() and Release()) when passing it. */ RefPtr 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 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 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 FindSnapPointNear(const CSSPoint& aDestination, nsIScrollableFrame::ScrollUnit aUnit); }; } // namespace layers } // namespace mozilla #endif // mozilla_layers_PanZoomController_h