Add m-esr52 at 52.6.0

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 000000000..deec37b47
--- /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 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_GenericFlingAnimation_h_
+#define mozilla_layers_GenericFlingAnimation_h_
+
+#include "APZUtils.h"
+#include "AsyncPanZoomAnimation.h"
+#include "AsyncPanZoomController.h"
+#include "FrameMetrics.h"
+#include "Layers.h"
+#include "Units.h"
+#include "OverscrollHandoffState.h"
+#include "gfxPrefs.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Monitor.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/TimeStamp.h"
+#include "nsThreadUtils.h"
+
+#define FLING_LOG(...)
+// #define FLING_LOG(...) printf_stderr("FLING: " __VA_ARGS__)
+
+namespace mozilla {
+namespace layers {
+
+class GenericFlingAnimation: public AsyncPanZoomAnimation {
+public:
+  GenericFlingAnimation(AsyncPanZoomController& aApzc,
+                        PlatformSpecificStateBase* aPlatformSpecificState,
+                        const RefPtr<const OverscrollHandoffChain>& aOverscrollHandoffChain,
+                        bool aFlingIsHandedOff,
+                        const RefPtr<const AsyncPanZoomController>& aScrolledApzc)
+    : mApzc(aApzc)
+    , mOverscrollHandoffChain(aOverscrollHandoffChain)
+    , mScrolledApzc(aScrolledApzc)
+  {
+    MOZ_ASSERT(mOverscrollHandoffChain);
+    TimeStamp now = aApzc.GetFrameTime();
+
+    // 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, Layer::HORIZONTAL)) {
+      ReentrantMonitorAutoEnter lock(mApzc.mMonitor);
+      mApzc.mX.SetVelocity(0);
+    }
+    if (!mOverscrollHandoffChain->CanScrollInDirection(&mApzc, Layer::VERTICAL)) {
+      ReentrantMonitorAutoEnter lock(mApzc.mMonitor);
+      mApzc.mY.SetVelocity(0);
+    }
+
+    ParentLayerPoint velocity = mApzc.GetVelocityVector();
+
+    // If the last fling was very recent and in the same direction as this one,
+    // boost the velocity to be the sum of the two. Check separate axes separately
+    // because we could have two vertical flings with small horizontal components
+    // on the opposite side of zero, and we still want the y-fling to get accelerated.
+    // Note that the acceleration code is only applied on the APZC that initiates
+    // the fling; the accelerated velocities are then handed off using the
+    // normal DispatchFling codepath.
+    // Acceleration is only applied in the APZC that originated the fling,
+    // not in APZCs further down the handoff chain during handoff.
+    bool applyAcceleration = !aFlingIsHandedOff;
+    if (applyAcceleration && !mApzc.mLastFlingTime.IsNull()
+        && (now - mApzc.mLastFlingTime).ToMilliseconds() < gfxPrefs::APZFlingAccelInterval()
+        && velocity.Length() >= gfxPrefs::APZFlingAccelMinVelocity()) {
+      if (SameDirection(velocity.x, mApzc.mLastFlingVelocity.x)) {
+        velocity.x = Accelerate(velocity.x, mApzc.mLastFlingVelocity.x);
+        FLING_LOG("%p Applying fling x-acceleration from %f to %f (delta %f)\n",
+                  &mApzc, mApzc.mX.GetVelocity(), velocity.x, mApzc.mLastFlingVelocity.x);
+        mApzc.mX.SetVelocity(velocity.x);
+      }
+      if (SameDirection(velocity.y, mApzc.mLastFlingVelocity.y)) {
+        velocity.y = Accelerate(velocity.y, mApzc.mLastFlingVelocity.y);
+        FLING_LOG("%p Applying fling y-acceleration from %f to %f (delta %f)\n",
+                  &mApzc, mApzc.mY.GetVelocity(), velocity.y, mApzc.mLastFlingVelocity.y);
+        mApzc.mY.SetVelocity(velocity.y);
+      }
+    }
+
+    mApzc.mLastFlingTime = now;
+    mApzc.mLastFlingVelocity = velocity;
+  }
+
+  /**
+   * 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
+  {
+    float friction = gfxPrefs::APZFlingFriction();
+    float threshold = gfxPrefs::APZFlingStoppedThreshold();
+
+    bool shouldContinueFlingX = mApzc.mX.FlingApplyFrictionOrCancel(aDelta, friction, threshold),
+         shouldContinueFlingY = mApzc.mY.FlingApplyFrictionOrCancel(aDelta, friction, threshold);
+    // If we shouldn't continue the fling, let's just stop and repaint.
+    if (!shouldContinueFlingX && !shouldContinueFlingY) {
+      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 mMonitor, 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*>(mOverscrollHandoffChain.get(),
+                                                       &OverscrollHandoffChain::SnapBackOverscrolledApzc,
+                                                       &mApzc));
+      return false;
+    }
+
+    // AdjustDisplacement() zeroes out the Axis velocity if we're in overscroll.
+    // Since we need to hand off the velocity to the tree manager in such a case,
+    // we save it here. Would be ParentLayerVector instead of ParentLayerPoint
+    // if we had vector classes.
+    ParentLayerPoint velocity = mApzc.GetVelocityVector();
+
+    ParentLayerPoint offset = velocity * aDelta.ToMilliseconds();
+
+    // 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);
+
+    aFrameMetrics.ScrollBy(adjustedOffset / aFrameMetrics.GetZoom());
+
+    // The fling may have caused us to reach the end of our scroll range.
+    if (!IsZero(overscroll)) {
+      // 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 (FuzzyEqualsAdditive(overscroll.x, 0.0f, COORDINATE_EPSILON)) {
+        velocity.x = 0;
+      } else if (FuzzyEqualsAdditive(overscroll.y, 0.0f, COORDINATE_EPSILON)) {
+        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 mMonitor, so directly calling
+      // HandleFlingOverscroll() (which acquires the tree lock) would violate
+      // the lock ordering. Instead we schedule HandleFlingOverscroll() to be
+      // called after mMonitor is released.
+      FLING_LOG("%p fling went into overscroll, handing off with velocity %s\n", &mApzc, Stringify(velocity).c_str());
+      mDeferredTasks.AppendElement(
+          NewRunnableMethod<ParentLayerPoint,
+                            RefPtr<const OverscrollHandoffChain>,
+                            RefPtr<const AsyncPanZoomController>>(&mApzc,
+                                                                  &AsyncPanZoomController::HandleFlingOverscroll,
+                                                                  velocity,
+                                                                  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());
+    }
+
+    return true;
+  }
+
+private:
+  static bool SameDirection(float aVelocity1, float aVelocity2)
+  {
+    return (aVelocity1 == 0.0f)
+        || (aVelocity2 == 0.0f)
+        || (IsNegative(aVelocity1) == IsNegative(aVelocity2));
+  }
+
+  static float Accelerate(float aBase, float aSupplemental)
+  {
+    return (aBase * gfxPrefs::APZFlingAccelBaseMultiplier())
+         + (aSupplemental * gfxPrefs::APZFlingAccelSupplementalMultiplier());
+  }
+
+  AsyncPanZoomController& mApzc;
+  RefPtr<const OverscrollHandoffChain> mOverscrollHandoffChain;
+  RefPtr<const AsyncPanZoomController> mScrolledApzc;
+};
+
+} // namespace layers
+} // namespace mozilla
+
+#endif // mozilla_layers_GenericFlingAnimation_h_