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/macros.h"
9 #include "third_party/skia/include/core/SkColor.h"
10 #include "ui/gfx/animation/animation_export.h"
11 #include "ui/gfx/geometry/rect.h"
12 #include "ui/gfx/geometry/rect_f.h"
13 #include "ui/gfx/geometry/size_f.h"
14 #include "ui/gfx/transform.h"
15 
16 namespace base {
17 class TimeTicks;
18 }
19 
20 namespace gfx {
21 
22 class ANIMATION_EXPORT Tween {
23  public:
24   enum Type {
25     LINEAR,              // Linear.
26     EASE_OUT,            // Fast in, slow out (default).
27     EASE_OUT_2,          // Variant of EASE_OUT that ends slower than EASE_OUT.
28     EASE_IN,             // Slow in, fast out.
29     EASE_IN_2,           // Variant of EASE_IN that starts out slower than
30                          // EASE_IN.
31     EASE_IN_OUT,         // Slow in and out, fast in the middle.
32     EASE_IN_OUT_2,       // Variant of EASE_IN_OUT that starts and ends slower
33                          // than EASE_IN_OUT.
34     SMOOTH_IN_OUT,       // Smooth, consistent speeds in and out (sine wave).
35     FAST_OUT_SLOW_IN,    // Variant of EASE_IN_OUT which should be used in most
36                          // cases.
37     FAST_OUT_SLOW_IN_2,  // Variant of FAST_OUT_SLOW_IN that starts out quicker.
38     LINEAR_OUT_SLOW_IN,  // Variant of EASE_OUT which should be used for
39                          // fading in from 0% or motion when entering a scene.
40     SLOW_OUT_LINEAR_IN,  // Reverse of LINEAR_OUT_SLOW_IN which should be used
41                          // in reverse animation to create a rubberband effect.
42     FAST_OUT_LINEAR_IN,  // Variant of EASE_IN which should should be used for
43                          // fading out to 0% or motion when exiting a scene.
44     ZERO,                // Returns a value of 0 always.
45   };
46 
47   // Returns the value based on the tween type. |state| is from 0-1.
48   static double CalculateValue(Type type, double state);
49 
50   // Conveniences for getting a value between a start and end point.
51   static SkColor ColorValueBetween(double value, SkColor start, SkColor target);
52   static double DoubleValueBetween(double value, double start, double target);
53   static float FloatValueBetween(double value, float start, float target);
54   static float ClampedFloatValueBetween(const base::TimeTicks& time,
55                                         const base::TimeTicks& start_time,
56                                         float start,
57                                         const base::TimeTicks& target_time,
58                                         float target);
59 
60   // Interpolated between start and target, with every integer in this range
61   // given equal weight.
62   static int IntValueBetween(double value, int start, int target);
63 
64   // Interpolates between start and target as real numbers, and rounds the
65   // result to the nearest integer, with ties broken by rounding towards
66   // positive infinity. This gives start and target half the weight of the
67   // other integers in the range. This is the integer interpolation approach
68   // specified by www.w3.org/TR/css3-transitions.
69   static int LinearIntValueBetween(double value, int start, int target);
70 
71   // Interpolates between |start| and |target| rects, animating the rect corners
72   // (as opposed to animating the rect origin and size) to minimize rounding
73   // error accumulation at intermediate stages.
74   static gfx::Rect RectValueBetween(double value,
75                                     const gfx::Rect& start,
76                                     const gfx::Rect& target);
77 
78   static gfx::RectF RectFValueBetween(double value,
79                                       const gfx::RectF& start,
80                                       const gfx::RectF& target);
81 
82   static gfx::Transform TransformValueBetween(double value,
83                                               const gfx::Transform& start,
84                                               const gfx::Transform& target);
85 
86   static gfx::Size SizeValueBetween(double value,
87                                     const gfx::Size& start,
88                                     const gfx::Size& target);
89 
90   static gfx::SizeF SizeFValueBetween(double value,
91                                       const gfx::SizeF& start,
92                                       const gfx::SizeF& target);
93 
94  private:
95   Tween();
96   ~Tween();
97 
98   DISALLOW_COPY_AND_ASSIGN(Tween);
99 };
100 
101 }  // namespace gfx
102 
103 #endif  // UI_GFX_ANIMATION_TWEEN_H_
104