1 files changed, 45 insertions, 0 deletions
diff --git a/gfx/layers/apz/src/AndroidFlingPhysics.h b/gfx/layers/apz/src/AndroidFlingPhysics.h
new file mode 100644
index 0000000000..68fb53e804
--- /dev/null
+++ b/gfx/layers/apz/src/AndroidFlingPhysics.h
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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
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_layers_AndroidFlingPhysics_h_
+#define mozilla_layers_AndroidFlingPhysics_h_
+
+#include "AsyncPanZoomController.h"
+#include "Units.h"
+#include "mozilla/Assertions.h"
+
+namespace mozilla {
+namespace layers {
+
+class AndroidFlingPhysics {
+ public:
+  void Init(const ParentLayerPoint& aVelocity, float aPLPPI);
+  void Sample(const TimeDuration& aDelta, ParentLayerPoint* aOutVelocity,
+              ParentLayerPoint* aOutOffset);
+
+  static void InitializeGlobalState();
+
+ private:
+  // Returns false if the animation should end.
+  bool SampleImpl(const TimeDuration& aDelta, float* aOutVelocity);
+
+  // Information pertaining to the current fling.
+  // This is initialized on each call to Init().
+  ParentLayerCoord mVelocity;  // diagonal velocity (length of velocity vector)
+  TimeDuration mTargetDuration;
+  TimeDuration mDurationSoFar;
+  ParentLayerPoint mLastPos;
+  ParentLayerPoint mCurrentPos;
+  ParentLayerCoord mTargetDistance;  // diagonal distance
+  ParentLayerPoint mTargetPos;       // really a target *offset* relative to the
+                                     // start position, which we don't track
+  ParentLayerPoint mDeltaNorm;       // mTargetPos with length normalized to 1
+};
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif  // mozilla_layers_AndroidFlingPhysics_h_