summaryrefslogtreecommitdiffstats
path: root/layout/generic/ScrollAnimationMSDPhysics.h
blob: b2d50be8d91ce123143d949410a046a79377fc2a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
/* -*- 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_layout_ScrollAnimationMSDPhysics_h_
#define mozilla_layout_ScrollAnimationMSDPhysics_h_

#include "ScrollAnimationPhysics.h"
#include "mozilla/layers/AxisPhysicsMSDModel.h"

namespace mozilla {

// This class implements a cubic MSD timing function and automatically
// adapts the animation duration based on the scrolling rate.
class ScrollAnimationMSDPhysics final : public ScrollAnimationPhysics {
 public:
  typedef mozilla::layers::AxisPhysicsMSDModel AxisPhysicsMSDModel;

  explicit ScrollAnimationMSDPhysics(const nsPoint& aStartPos);

  void Update(const TimeStamp& aTime, const nsPoint& aDestination,
              const nsSize& aCurrentVelocity) override;

  void ApplyContentShift(const CSSPoint& aShiftDelta) override;

  // Get the velocity at a point in time in nscoords/sec.
  nsSize VelocityAt(const TimeStamp& aTime) override;

  // Returns the expected scroll position at a given point in time, in app
  // units, relative to the scroll frame.
  nsPoint PositionAt(const TimeStamp& aTime) override;

  bool IsFinished(const TimeStamp& aTime) override {
    SimulateUntil(aTime);
    return mModelX.IsFinished(1) && mModelY.IsFinished(1);
  }

 protected:
  double ComputeSpringConstant(const TimeStamp& aTime);
  void SimulateUntil(const TimeStamp& aTime);

  TimeStamp mPreviousEventTime;
  TimeDuration mPreviousDelta;

  TimeStamp mStartTime;

  nsPoint mStartPos;
  nsPoint mDestination;
  nsPoint mContentShift;
  TimeStamp mLastSimulatedTime;
  AxisPhysicsMSDModel mModelX;
  AxisPhysicsMSDModel mModelY;
  bool mIsFirstIteration;
};

}  // namespace mozilla

#endif  // mozilla_layout_ScrollAnimationMSDPhysics_h_