Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 207 insertions, 0 deletions

diff --git a/gfx/layers/apz/src/GenericFlingAnimation.h b/gfx/layers/apz/src/GenericFlingAnimation.h
new file mode 100644
index 0000000000..82f981ae0a
--- /dev/null
+++ b/gfx/layers/apz/src/GenericFlingAnimation.h
@@ -0,0 +1,207 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_layers_GenericFlingAnimation_h_
+#define mozilla_layers_GenericFlingAnimation_h_
+
+#include "APZUtils.h"
+#include "AsyncPanZoomAnimation.h"
+#include "AsyncPanZoomController.h"
+#include "FrameMetrics.h"
+#include "Units.h"
+#include "OverscrollHandoffState.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Monitor.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/StaticPrefs_apz.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/ToString.h"
+#include "nsThreadUtils.h"
+
+static mozilla::LazyLogModule sApzFlgLog("apz.fling");
+#define FLING_LOG(...) MOZ_LOG(sApzFlgLog, LogLevel::Debug, (__VA_ARGS__))
+
+namespace mozilla {
+namespace layers {
+
+/**
+ * The FlingPhysics template parameter determines the physics model
+ * that the fling animation follows. It must have the following methods:
+ *
+ *   - Default constructor.
+ *
+ *   - Init(const ParentLayerPoint& aStartingVelocity, float aPLPPI).
+ *     Called at the beginning of the fling, with the fling's starting velocity,
+ *     and the number of ParentLayer pixels per (Screen) inch at the point of
+ *     the fling's start in the fling's direction.
+ *
+ *   - Sample(const TimeDuration& aDelta,
+ *            ParentLayerPoint* aOutVelocity,
+ *            ParentLayerPoint* aOutOffset);
+ *     Called on each sample of the fling.
+ *     |aDelta| is the time elapsed since the last sample.
+ *     |aOutVelocity| should be the desired velocity after the current sample,
+ *                    in ParentLayer pixels per millisecond.
+ *     |aOutOffset| should be the desired _delta_ to the scroll offset after
+ *     the current sample. |aOutOffset| should _not_ be clamped to the APZC's
+ *     scrollable bounds; the caller will do the clamping, and it needs to
+ *     know the unclamped value to handle handoff/overscroll correctly.
+ */
+template <typename FlingPhysics>
+class GenericFlingAnimation : public AsyncPanZoomAnimation,
+                              public FlingPhysics {
+ public:
+  GenericFlingAnimation(AsyncPanZoomController& aApzc,
+                        const FlingHandoffState& aHandoffState, float aPLPPI)
+      : mApzc(aApzc),
+        mOverscrollHandoffChain(aHandoffState.mChain),
+        mScrolledApzc(aHandoffState.mScrolledApzc) {
+    MOZ_ASSERT(mOverscrollHandoffChain);
+
+    // Drop any velocity on axes where we don't have room to scroll anyways
+    // (in this APZC, or an APZC further in the handoff chain).
+    // This ensures that we don't take the 'overscroll' path in Sample()
+    // on account of one axis which can't scroll having a velocity.
+    if (!mOverscrollHandoffChain->CanScrollInDirection(
+            &mApzc, ScrollDirection::eHorizontal)) {
+      RecursiveMutexAutoLock lock(mApzc.mRecursiveMutex);
+      mApzc.mX.SetVelocity(0);
+    }
+    if (!mOverscrollHandoffChain->CanScrollInDirection(
+            &mApzc, ScrollDirection::eVertical)) {
+      RecursiveMutexAutoLock lock(mApzc.mRecursiveMutex);
+      mApzc.mY.SetVelocity(0);
+    }
+
+    if (aHandoffState.mIsHandoff) {
+      // Only apply acceleration in the APZC that originated the fling, not in
+      // APZCs further down the handoff chain during handoff.
+      mApzc.mFlingAccelerator.Reset();
+    }
+
+    ParentLayerPoint velocity =
+        mApzc.mFlingAccelerator.GetFlingStartingVelocity(
+            aApzc.GetFrameTime(), mApzc.GetVelocityVector(), aHandoffState);
+
+    mApzc.SetVelocityVector(velocity);
+
+    FlingPhysics::Init(mApzc.GetVelocityVector(), aPLPPI);
+  }
+
+  /**
+   * Advances a fling by an interpolated amount based on the passed in |aDelta|.
+   * This should be called whenever sampling the content transform for this
+   * frame. Returns true if the fling animation should be advanced by one frame,
+   * or false if there is no fling or the fling has ended.
+   */
+  virtual bool DoSample(FrameMetrics& aFrameMetrics,
+                        const TimeDuration& aDelta) override {
+    CSSToParentLayerScale zoom(aFrameMetrics.GetZoom());
+    if (zoom == CSSToParentLayerScale(0)) {
+      return false;
+    }
+
+    ParentLayerPoint velocity;
+    ParentLayerPoint offset;
+    FlingPhysics::Sample(aDelta, &velocity, &offset);
+
+    mApzc.SetVelocityVector(velocity);
+
+    // If we shouldn't continue the fling, let's just stop and repaint.
+    if (IsZero(velocity / zoom)) {
+      FLING_LOG("%p ending fling animation. overscrolled=%d\n", &mApzc,
+                mApzc.IsOverscrolled());
+      // This APZC or an APZC further down the handoff chain may be be
+      // overscrolled. Start a snap-back animation on the overscrolled APZC.
+      // Note:
+      //   This needs to be a deferred task even though it can safely run
+      //   while holding mRecursiveMutex, because otherwise, if the overscrolled
+      //   APZC is this one, then the SetState(NOTHING) in UpdateAnimation will
+      //   stomp on the SetState(SNAP_BACK) it does.
+      mDeferredTasks.AppendElement(NewRunnableMethod<AsyncPanZoomController*>(
+          "layers::OverscrollHandoffChain::SnapBackOverscrolledApzc",
+          mOverscrollHandoffChain.get(),
+          &OverscrollHandoffChain::SnapBackOverscrolledApzc, &mApzc));
+      return false;
+    }
+
+    // Ordinarily we might need to do a ScheduleComposite if either of
+    // the following AdjustDisplacement calls returns true, but this
+    // is already running as part of a FlingAnimation, so we'll be compositing
+    // per frame of animation anyway.
+    ParentLayerPoint overscroll;
+    ParentLayerPoint adjustedOffset;
+    mApzc.mX.AdjustDisplacement(offset.x, adjustedOffset.x, overscroll.x);
+    mApzc.mY.AdjustDisplacement(offset.y, adjustedOffset.y, overscroll.y);
+    if (aFrameMetrics.GetZoom() != CSSToParentLayerScale(0)) {
+      mApzc.ScrollBy(adjustedOffset / aFrameMetrics.GetZoom());
+    }
+
+    // The fling may have caused us to reach the end of our scroll range.
+    if (!IsZero(overscroll / zoom)) {
+      // Hand off the fling to the next APZC in the overscroll handoff chain.
+
+      // We may have reached the end of the scroll range along one axis but
+      // not the other. In such a case we only want to hand off the relevant
+      // component of the fling.
+      if (mApzc.IsZero(overscroll.x)) {
+        velocity.x = 0;
+      } else if (mApzc.IsZero(overscroll.y)) {
+        velocity.y = 0;
+      }
+
+      // To hand off the fling, we attempt to find a target APZC and start a new
+      // fling with the same velocity on that APZC. For simplicity, the actual
+      // overscroll of the current sample is discarded rather than being handed
+      // off. The compositor should sample animations sufficiently frequently
+      // that this is not noticeable. The target APZC is chosen by seeing if
+      // there is an APZC further in the handoff chain which is pannable; if
+      // there isn't, we take the new fling ourselves, entering an overscrolled
+      // state.
+      // Note: APZC is holding mRecursiveMutex, so directly calling
+      // HandleFlingOverscroll() (which acquires the tree lock) would violate
+      // the lock ordering. Instead we schedule HandleFlingOverscroll() to be
+      // called after mRecursiveMutex is released.
+      FLING_LOG("%p fling went into overscroll, handing off with velocity %s\n",
+                &mApzc, ToString(velocity).c_str());
+      mDeferredTasks.AppendElement(
+          NewRunnableMethod<ParentLayerPoint, SideBits,
+                            RefPtr<const OverscrollHandoffChain>,
+                            RefPtr<const AsyncPanZoomController>>(
+              "layers::AsyncPanZoomController::HandleFlingOverscroll", &mApzc,
+              &AsyncPanZoomController::HandleFlingOverscroll, velocity,
+              apz::GetOverscrollSideBits(overscroll), mOverscrollHandoffChain,
+              mScrolledApzc));
+
+      // If there is a remaining velocity on this APZC, continue this fling
+      // as well. (This fling and the handed-off fling will run concurrently.)
+      // Note that AdjustDisplacement() will have zeroed out the velocity
+      // along the axes where we're overscrolled.
+      return !IsZero(mApzc.GetVelocityVector() / zoom);
+    }
+
+    return true;
+  }
+
+  void Cancel(CancelAnimationFlags aFlags) override {
+    mApzc.mFlingAccelerator.ObserveFlingCanceled(mApzc.GetVelocityVector());
+  }
+
+  virtual bool HandleScrollOffsetUpdate(
+      const Maybe<CSSPoint>& aRelativeDelta) override {
+    return true;
+  }
+
+ private:
+  AsyncPanZoomController& mApzc;
+  RefPtr<const OverscrollHandoffChain> mOverscrollHandoffChain;
+  RefPtr<const AsyncPanZoomController> mScrolledApzc;
+};
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif  // mozilla_layers_GenericFlingAnimation_h_