1// Copyright 2011 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef CC_INPUT_PAGE_SCALE_ANIMATION_H_
6#define CC_INPUT_PAGE_SCALE_ANIMATION_H_
7
8#include "base/basictypes.h"
9#include "base/memory/scoped_ptr.h"
10#include "ui/gfx/size.h"
11#include "ui/gfx/vector2d_f.h"
12
13namespace cc {
14class TimingFunction;
15
16// A small helper class that does the math for zoom animations, primarily for
17// double-tap zoom. Initialize it with starting and ending scroll/page scale
18// positions and an animation length time, then call ...AtTime() at every frame
19// to obtain the current interpolated position. The supplied timing function
20// is used to ease the animation.
21//
22// All sizes and vectors in this class's public methods are in the root scroll
23// layer's coordinate space.
24class PageScaleAnimation {
25 public:
26  // Construct with the state at the beginning of the animation.
27  static scoped_ptr<PageScaleAnimation> Create(
28      gfx::Vector2dF start_scroll_offset,
29      float start_page_scale_factor,
30      gfx::SizeF viewport_size,
31      gfx::SizeF root_layer_size,
32      double start_time,
33      scoped_ptr<TimingFunction> timing_function);
34
35  ~PageScaleAnimation();
36
37  // The following methods initialize the animation. Call one of them
38  // immediately after construction to set the final scroll and page scale.
39
40  // Zoom while explicitly specifying the top-left scroll position.
41  void ZoomTo(gfx::Vector2dF target_scroll_offset,
42              float target_page_scale_factor,
43              double duration);
44
45  // Zoom based on a specified anchor. The animator will attempt to keep it
46  // at the same position on the physical display throughout the animation,
47  // unless the edges of the root layer are hit. The anchor is specified
48  // as an offset from the content layer.
49  void ZoomWithAnchor(gfx::Vector2dF anchor,
50                      float target_page_scale_factor,
51                      double duration);
52
53  // Call these functions while the animation is in progress to output the
54  // current state.
55  gfx::Vector2dF ScrollOffsetAtTime(double time) const;
56  float PageScaleFactorAtTime(double time) const;
57  bool IsAnimationCompleteAtTime(double time) const;
58
59  // The following methods return state which is invariant throughout the
60  // course of the animation.
61  double start_time() const { return start_time_; }
62  double duration() const { return duration_; }
63  double end_time() const { return start_time_ + duration_; }
64  gfx::Vector2dF target_scroll_offset() const { return target_scroll_offset_; }
65  float target_page_scale_factor() const { return target_page_scale_factor_; }
66
67 protected:
68  PageScaleAnimation(gfx::Vector2dF start_scroll_offset,
69                     float start_page_scale_factor,
70                     gfx::SizeF viewport_size,
71                     gfx::SizeF root_layer_size,
72                     double start_time,
73                     scoped_ptr<TimingFunction> timing_function);
74
75 private:
76  void ClampTargetScrollOffset();
77  void InferTargetScrollOffsetFromStartAnchor();
78  void InferTargetAnchorFromScrollOffsets();
79
80  gfx::SizeF StartViewportSize() const;
81  gfx::SizeF TargetViewportSize() const;
82  float InterpAtTime(double time) const;
83  gfx::SizeF ViewportSizeAt(float interp) const;
84  gfx::Vector2dF ScrollOffsetAt(float interp) const;
85  gfx::Vector2dF AnchorAt(float interp) const;
86  gfx::Vector2dF ViewportRelativeAnchorAt(float interp) const;
87  float PageScaleFactorAt(float interp) const;
88
89  float start_page_scale_factor_;
90  float target_page_scale_factor_;
91  gfx::Vector2dF start_scroll_offset_;
92  gfx::Vector2dF target_scroll_offset_;
93
94  gfx::Vector2dF start_anchor_;
95  gfx::Vector2dF target_anchor_;
96
97  gfx::SizeF viewport_size_;
98  gfx::SizeF root_layer_size_;
99
100  double start_time_;
101  double duration_;
102
103  scoped_ptr<TimingFunction> timing_function_;
104
105  DISALLOW_COPY_AND_ASSIGN(PageScaleAnimation);
106};
107
108}  // namespace cc
109
110#endif  // CC_INPUT_PAGE_SCALE_ANIMATION_H_
111