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Mypal/gfx/layers/apz/src/AsyncPanZoomController.h

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/* -*- 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
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