ui/gfx/animation/tween.h

   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
  14 namespace gfx {
  15
  16 class 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_