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.
23    EASE_IN_OUT,   // Slow in and out, fast in the middle.
24    FAST_IN_OUT,   // Fast in and out, slow in the middle.
25    EASE_OUT_SNAP, // Fast in, slow out, snap to final value.
26    SMOOTH_IN_OUT, // Smooth, consistent speeds in and out (sine wave).
27    ZERO,          // Returns a value of 0 always.
28  };
29
30  // Returns the value based on the tween type. |state| is from 0-1.
31  static double CalculateValue(Type type, double state);
32
33  // Conveniences for getting a value between a start and end point.
34  static SkColor ColorValueBetween(double value, SkColor start, SkColor target);
35  static double DoubleValueBetween(double value, double start, double target);
36  static float FloatValueBetween(double value, float start, float target);
37
38  // Interpolated between start and target, with every integer in this range
39  // given equal weight.
40  static int IntValueBetween(double value, int start, int target);
41
42  // Interpolates between start and target as real numbers, and rounds the
43  // result to the nearest integer, with ties broken by rounding towards
44  // positive infinity. This gives start and target half the weight of the
45  // other integers in the range. This is the integer interpolation approach
46  // specified by www.w3.org/TR/css3-transitions.
47  static int LinearIntValueBetween(double value, int start, int target);
48  static gfx::Rect RectValueBetween(double value,
49                                    const gfx::Rect& start_bounds,
50                                    const gfx::Rect& target_bounds);
51  static gfx::Transform TransformValueBetween(
52      double value,
53      const gfx::Transform& start_transform,
54      const gfx::Transform& target_transform);
55
56 private:
57  Tween();
58  ~Tween();
59
60  DISALLOW_COPY_AND_ASSIGN(Tween);
61};
62
63}  // namespace gfx
64
65#endif  // UI_GFX_ANIMATION_TWEEN_H_
66