1// Copyright (c) 2012 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 UI_GFX_ANIMATION_TWEEN_H_
6#define UI_GFX_ANIMATION_TWEEN_H_
7
8#include "base/basictypes.h"
9#include "third_party/skia/include/core/SkColor.h"
10#include "ui/gfx/gfx_export.h"
11#include "ui/gfx/rect.h"
12#include "ui/gfx/transform.h"
13
14namespace gfx {
15
16class GFX_EXPORT Tween {
17 public:
18  enum Type {
19    LINEAR,             // Linear.
20    EASE_OUT,           // Fast in, slow out (default).
21    EASE_IN,            // Slow in, fast out.
22    EASE_IN_2,          // Variant of EASE_IN that starts out slower than
23                        // EASE_IN.
24    EASE_IN_OUT,        // Slow in and out, fast in the middle.
25    FAST_IN_OUT,        // Fast in and out, slow in the middle.
26    EASE_OUT_SNAP,      // Fast in, slow out, snap to final value.
27    SMOOTH_IN_OUT,      // Smooth, consistent speeds in and out (sine wave).
28    FAST_OUT_SLOW_IN,   // Variant of EASE_IN_OUT which should be used in most
29                        // cases.
30    LINEAR_OUT_SLOW_IN, // Variant of EASE_OUT which should be used for
31                        // fading in from 0% or motion when entering a scene.
32    FAST_OUT_LINEAR_IN, // Variant of EASE_IN which should should be used for
33                        // fading out to 0% or motion when exiting a scene.
34    ZERO,               // Returns a value of 0 always.
35  };
36
37  // Returns the value based on the tween type. |state| is from 0-1.
38  static double CalculateValue(Type type, double state);
39
40  // Conveniences for getting a value between a start and end point.
41  static SkColor ColorValueBetween(double value, SkColor start, SkColor target);
42  static double DoubleValueBetween(double value, double start, double target);
43  static float FloatValueBetween(double value, float start, float target);
44
45  // Interpolated between start and target, with every integer in this range
46  // given equal weight.
47  static int IntValueBetween(double value, int start, int target);
48
49  // Interpolates between start and target as real numbers, and rounds the
50  // result to the nearest integer, with ties broken by rounding towards
51  // positive infinity. This gives start and target half the weight of the
52  // other integers in the range. This is the integer interpolation approach
53  // specified by www.w3.org/TR/css3-transitions.
54  static int LinearIntValueBetween(double value, int start, int target);
55  static gfx::Rect RectValueBetween(double value,
56                                    const gfx::Rect& start_bounds,
57                                    const gfx::Rect& target_bounds);
58  static gfx::Transform TransformValueBetween(
59      double value,
60      const gfx::Transform& start_transform,
61      const gfx::Transform& target_transform);
62
63 private:
64  Tween();
65  ~Tween();
66
67  DISALLOW_COPY_AND_ASSIGN(Tween);
68};
69
70}  // namespace gfx
71
72#endif  // UI_GFX_ANIMATION_TWEEN_H_
73