src/ui/gfx/animation/tween.cc

   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 #include "ui/gfx/animation/tween.h"
   6
   7 #include <math.h>
   8
   9 #if defined(OS_WIN)
  10 #include <float.h>
  11 #endif
  12
  13 #include <algorithm>
  14
  15 #include "base/basictypes.h"
  16 #include "base/logging.h"
  17 #include "base/numerics/safe_conversions.h"
  18 #include "ui/gfx/geometry/cubic_bezier.h"
  19 #include "ui/gfx/safe_integer_conversions.h"
  20
  21 namespace gfx {
  22
  23 // static
  24 double Tween::CalculateValue(Tween::Type type, double state) {
  25   DCHECK_GE(state, 0);
  26   DCHECK_LE(state, 1);
  27
  28   switch (type) {
  29     case EASE_IN:
  30       return pow(state, 2);
  31
  32     case EASE_IN_2:
  33       return pow(state, 4);
  34
  35     case EASE_IN_OUT:
  36       if (state < 0.5)
  37         return pow(state * 2, 2) / 2.0;
  38       return 1.0 - (pow((state - 1.0) * 2, 2) / 2.0);
  39
  40     case FAST_IN_OUT:
  41       return (pow(state - 0.5, 3) + 0.125) / 0.25;
  42
  43     case LINEAR:
  44       return state;
  45
  46     case EASE_OUT_SNAP:
  47       state = 0.95 * (1.0 - pow(1.0 - state, 2));
  48       return state;
  49
  50     case EASE_OUT:
  51       return 1.0 - pow(1.0 - state, 2);
  52
  53     case SMOOTH_IN_OUT:
  54       return sin(state);
  55
  56     case FAST_OUT_SLOW_IN:
  57       return gfx::CubicBezier(0.4, 0, 0.2, 1).Solve(state);
  58
  59     case LINEAR_OUT_SLOW_IN:
  60       return gfx::CubicBezier(0, 0, .2, 1).Solve(state);
  61
  62     case FAST_OUT_LINEAR_IN:
  63       return gfx::CubicBezier(0.4, 0, 1, 1).Solve(state);
  64
  65     case ZERO:
  66       return 0;
  67   }
  68
  69   NOTREACHED();
  70   return state;
  71 }
  72
  73 namespace {
  74 uint8 FloatToColorByte(float f) {
  75   return base::saturated_cast<uint8>(ToRoundedInt(f * 255.f));
  76 }
  77
  78 uint8 BlendColorComponents(uint8 start,
  79                            uint8 target,
  80                            float start_alpha,
  81                            float target_alpha,
  82                            float blended_alpha,
  83                            double progress) {
  84   // Since progress can be outside [0, 1], blending can produce a value outside
  85   // [0, 255].
  86   float blended_premultiplied = Tween::FloatValueBetween(
  87       progress, start / 255.f * start_alpha, target / 255.f * target_alpha);
  88   return FloatToColorByte(blended_premultiplied / blended_alpha);
  89 }
  90
  91 }  // namespace
  92
  93 // static
  94 SkColor Tween::ColorValueBetween(double value, SkColor start, SkColor target) {
  95   float start_a = SkColorGetA(start) / 255.f;
  96   float target_a = SkColorGetA(target) / 255.f;
  97   float blended_a = FloatValueBetween(value, start_a, target_a);
  98   if (blended_a <= 0.f)
  99     return SkColorSetARGB(0, 0, 0, 0);
 100   blended_a = std::min(blended_a, 1.f);
 101
 102   uint8 blended_r = BlendColorComponents(SkColorGetR(start),
 103                                          SkColorGetR(target),
 104                                          start_a,
 105                                          target_a,
 106                                          blended_a,
 107                                          value);
 108   uint8 blended_g = BlendColorComponents(SkColorGetG(start),
 109                                          SkColorGetG(target),
 110                                          start_a,
 111                                          target_a,
 112                                          blended_a,
 113                                          value);
 114   uint8 blended_b = BlendColorComponents(SkColorGetB(start),
 115                                          SkColorGetB(target),
 116                                          start_a,
 117                                          target_a,
 118                                          blended_a,
 119                                          value);
 120
 121   return SkColorSetARGB(
 122       FloatToColorByte(blended_a), blended_r, blended_g, blended_b);
 123 }
 124
 125 // static
 126 double Tween::DoubleValueBetween(double value, double start, double target) {
 127   return start + (target - start) * value;
 128 }
 129
 130 // static
 131 float Tween::FloatValueBetween(double value, float start, float target) {
 132   return static_cast<float>(start + (target - start) * value);
 133 }
 134
 135 // static
 136 int Tween::IntValueBetween(double value, int start, int target) {
 137   if (start == target)
 138     return start;
 139   double delta = static_cast<double>(target - start);
 140   if (delta < 0)
 141     delta--;
 142   else
 143     delta++;
 144 #if defined(OS_WIN)
 145   return start + static_cast<int>(value * _nextafter(delta, 0));
 146 #else
 147   return start + static_cast<int>(value * nextafter(delta, 0));
 148 #endif
 149 }
 150
 151 //static
 152 int Tween::LinearIntValueBetween(double value, int start, int target) {
 153   // NOTE: Do not use ToRoundedInt()!  See comments on function declaration.
 154   return ToFlooredInt(0.5 + DoubleValueBetween(value, start, target));
 155 }
 156
 157 // static
 158 gfx::Rect Tween::RectValueBetween(double value,
 159                                   const gfx::Rect& start_bounds,
 160                                   const gfx::Rect& target_bounds) {
 161   return gfx::Rect(
 162       LinearIntValueBetween(value, start_bounds.x(), target_bounds.x()),
 163       LinearIntValueBetween(value, start_bounds.y(), target_bounds.y()),
 164       LinearIntValueBetween(value, start_bounds.width(), target_bounds.width()),
 165       LinearIntValueBetween(
 166           value, start_bounds.height(), target_bounds.height()));
 167 }
 168
 169 // static
 170 gfx::Transform Tween::TransformValueBetween(
 171     double value,
 172     const gfx::Transform& start_transform,
 173     const gfx::Transform& end_transform) {
 174   if (value >= 1.0)
 175     return end_transform;
 176   if (value <= 0.0)
 177     return start_transform;
 178
 179   gfx::Transform to_return = end_transform;
 180   to_return.Blend(start_transform, value);
 181
 182   return to_return;
 183 }
 184
 185 }  // namespace gfx