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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#ifndef mozilla_layers_Overscroll_h
#define mozilla_layers_Overscroll_h
#include "AsyncPanZoomAnimation.h"
#include "AsyncPanZoomController.h"
#include "mozilla/TimeStamp.h"
#include "nsThreadUtils.h"
namespace mozilla {
namespace layers {
// Animation used by GenericOverscrollEffect.
class OverscrollAnimation : public AsyncPanZoomAnimation {
public:
OverscrollAnimation(AsyncPanZoomController& aApzc,
const ParentLayerPoint& aVelocity,
SideBits aOverscrollSideBits)
: mApzc(aApzc), mOverscrollSideBits(aOverscrollSideBits) {
MOZ_ASSERT(
(mOverscrollSideBits & SideBits::eTopBottom) != SideBits::eTopBottom &&
(mOverscrollSideBits & SideBits::eLeftRight) !=
SideBits::eLeftRight,
"Don't allow overscrolling on both sides at the same time");
if ((aOverscrollSideBits & SideBits::eLeftRight) != SideBits::eNone) {
mApzc.mX.StartOverscrollAnimation(aVelocity.x);
}
if ((aOverscrollSideBits & SideBits::eTopBottom) != SideBits::eNone) {
mApzc.mY.StartOverscrollAnimation(aVelocity.y);
}
}
virtual ~OverscrollAnimation() {
mApzc.mX.EndOverscrollAnimation();
mApzc.mY.EndOverscrollAnimation();
}
virtual bool DoSample(FrameMetrics& aFrameMetrics,
const TimeDuration& aDelta) override {
// Can't inline these variables due to short-circuit evaluation.
bool continueX = mApzc.mX.IsOverscrollAnimationAlive() &&
mApzc.mX.SampleOverscrollAnimation(
aDelta, mOverscrollSideBits & SideBits::eLeftRight);
bool continueY = mApzc.mY.IsOverscrollAnimationAlive() &&
mApzc.mY.SampleOverscrollAnimation(
aDelta, mOverscrollSideBits & SideBits::eTopBottom);
if (!continueX && !continueY) {
// If we got into overscroll from a fling, that fling did not request a
// fling snap to avoid a resulting scrollTo from cancelling the overscroll
// animation too early. We do still want to request a fling snap, though,
// in case the end of the axis at which we're overscrolled is not a valid
// snap point, so we request one now. If there are no snap points, this
// will do nothing. If there are snap points, we'll get a scrollTo that
// snaps us back to the nearest valid snap point. The scroll snapping is
// done in a deferred task, otherwise the state change to NOTHING caused
// by the overscroll animation ending would clobber a possible state
// change to SMOOTH_SCROLL in ScrollSnap().
mDeferredTasks.AppendElement(NewRunnableMethod<ScrollSnapFlags>(
"layers::AsyncPanZoomController::ScrollSnap", &mApzc,
&AsyncPanZoomController::ScrollSnap,
ScrollSnapFlags::IntendedEndPosition));
return false;
}
return true;
}
virtual bool WantsRepaints() override { return false; }
// Tell the overscroll animation about the pan momentum event. For each axis,
// the overscroll animation may start, stop, or continue managing that axis in
// response to the pan momentum event
void HandlePanMomentum(const ParentLayerPoint& aDisplacement) {
float xOverscroll = mApzc.mX.GetOverscroll();
if ((xOverscroll > 0 && aDisplacement.x > 0) ||
(xOverscroll < 0 && aDisplacement.x < 0)) {
if (!mApzc.mX.IsOverscrollAnimationRunning()) {
// Start a new overscroll animation on this axis, if there is no
// overscroll animation running and if the pan momentum displacement
// the pan momentum displacement is the same direction of the current
// overscroll.
mApzc.mX.StartOverscrollAnimation(mApzc.mX.GetVelocity());
mOverscrollSideBits |=
xOverscroll > 0 ? SideBits::eRight : SideBits::eLeft;
}
} else if ((xOverscroll > 0 && aDisplacement.x < 0) ||
(xOverscroll < 0 && aDisplacement.x > 0)) {
// Otherwise, stop the animation in the direction so that it won't clobber
// subsequent pan momentum scrolling.
mApzc.mX.EndOverscrollAnimation();
}
// Same as above but for Y axis.
float yOverscroll = mApzc.mY.GetOverscroll();
if ((yOverscroll > 0 && aDisplacement.y > 0) ||
(yOverscroll < 0 && aDisplacement.y < 0)) {
if (!mApzc.mY.IsOverscrollAnimationRunning()) {
mApzc.mY.StartOverscrollAnimation(mApzc.mY.GetVelocity());
mOverscrollSideBits |=
yOverscroll > 0 ? SideBits::eBottom : SideBits::eTop;
}
} else if ((yOverscroll > 0 && aDisplacement.y < 0) ||
(yOverscroll < 0 && aDisplacement.y > 0)) {
mApzc.mY.EndOverscrollAnimation();
}
}
ScrollDirections GetDirections() const {
ScrollDirections directions;
if (mApzc.mX.IsOverscrollAnimationRunning()) {
directions += ScrollDirection::eHorizontal;
}
if (mApzc.mY.IsOverscrollAnimationRunning()) {
directions += ScrollDirection::eVertical;
}
return directions;
};
OverscrollAnimation* AsOverscrollAnimation() override { return this; }
bool IsManagingXAxis() const {
return mApzc.mX.IsOverscrollAnimationRunning();
}
bool IsManagingYAxis() const {
return mApzc.mY.IsOverscrollAnimationRunning();
}
private:
AsyncPanZoomController& mApzc;
SideBits mOverscrollSideBits;
};
// Base class for different overscroll effects;
class OverscrollEffectBase {
public:
virtual ~OverscrollEffectBase() = default;
// Try to increase the amount of overscroll by |aOverscroll|. Limited to
// directions contained in |aOverscrollableDirections|. Components of
// |aOverscroll| in directions that are successfully consumed are dropped.
virtual void ConsumeOverscroll(
ParentLayerPoint& aOverscroll,
ScrollDirections aOverscrollableDirections) = 0;
// Relieve overscroll. Depending on the implementation, the relief may
// be immediate, or gradual (e.g. after an animation) but this starts
// the process. |aVelocity| is the current velocity of the APZC, and
// |aOverscrollSideBits| contains the side(s) at which the APZC is
// overscrolled.
virtual void RelieveOverscroll(const ParentLayerPoint& aVelocity,
SideBits aOverscrollSideBits) = 0;
virtual bool IsOverscrolled() const = 0;
// Similarly to RelieveOverscroll(), but has immediate effect
// (no animation).
virtual void ClearOverscroll() = 0;
};
// A generic overscroll effect, implemented by AsyncPanZoomController itself.
class GenericOverscrollEffect : public OverscrollEffectBase {
public:
explicit GenericOverscrollEffect(AsyncPanZoomController& aApzc)
: mApzc(aApzc) {}
void ConsumeOverscroll(ParentLayerPoint& aOverscroll,
ScrollDirections aOverscrollableDirections) override {
if (aOverscrollableDirections.contains(ScrollDirection::eHorizontal)) {
mApzc.mX.OverscrollBy(aOverscroll.x);
aOverscroll.x = 0;
}
if (aOverscrollableDirections.contains(ScrollDirection::eVertical)) {
mApzc.mY.OverscrollBy(aOverscroll.y);
aOverscroll.y = 0;
}
if (!aOverscrollableDirections.isEmpty()) {
mApzc.ScheduleComposite();
}
}
void RelieveOverscroll(const ParentLayerPoint& aVelocity,
SideBits aOverscrollSideBits) override {
mApzc.StartOverscrollAnimation(aVelocity, aOverscrollSideBits);
}
bool IsOverscrolled() const override {
return mApzc.IsPhysicallyOverscrolled();
}
void ClearOverscroll() override { mApzc.ClearPhysicalOverscroll(); }
private:
AsyncPanZoomController& mApzc;
};
// A widget-specific overscroll effect, implemented by the widget via
// GeckoContentController.
class WidgetOverscrollEffect : public OverscrollEffectBase {
public:
explicit WidgetOverscrollEffect(AsyncPanZoomController& aApzc)
: mApzc(aApzc), mIsOverscrolled(false) {}
void ConsumeOverscroll(ParentLayerPoint& aOverscroll,
ScrollDirections aOverscrollableDirections) override {
RefPtr<GeckoContentController> controller =
mApzc.GetGeckoContentController();
if (controller && !aOverscrollableDirections.isEmpty()) {
mIsOverscrolled = true;
controller->UpdateOverscrollOffset(mApzc.GetGuid(), aOverscroll.x,
aOverscroll.y, mApzc.IsRootContent());
aOverscroll = ParentLayerPoint();
}
}
void RelieveOverscroll(const ParentLayerPoint& aVelocity,
SideBits aOverscrollSideBits) override {
RefPtr<GeckoContentController> controller =
mApzc.GetGeckoContentController();
// From APZC's point of view, consider it to no longer be overscrolled
// as soon as RelieveOverscroll() is called. The widget may use a
// delay or animation until the relieving of the overscroll is complete,
// but we don't have any insight into that.
mIsOverscrolled = false;
if (controller) {
controller->UpdateOverscrollVelocity(mApzc.GetGuid(), aVelocity.x,
aVelocity.y, mApzc.IsRootContent());
}
}
bool IsOverscrolled() const override { return mIsOverscrolled; }
void ClearOverscroll() override {
RelieveOverscroll(ParentLayerPoint(), SideBits() /* ignored */);
}
private:
AsyncPanZoomController& mApzc;
bool mIsOverscrolled;
};
} // namespace layers
} // namespace mozilla
#endif // mozilla_layers_Overscroll_h