app/tween.h

   1 // Copyright (c) 2010 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 APP_TWEEN_H_
   6 #define APP_TWEEN_H_
   7
   8 #include "base/logging.h"
   9
  10 namespace gfx {
  11 class Rect;
  12 }
  13
  14 class Tween {
  15  public:
  16   enum Type {
  17     LINEAR,        // Linear.
  18     EASE_OUT,      // Fast in, slow out (default).
  19     EASE_IN,       // Slow in, fast out.
  20     EASE_IN_OUT,   // Slow in and out, fast in the middle.
  21     FAST_IN_OUT,   // Fast in and out, slow in the middle.
  22     EASE_OUT_SNAP, // Fast in, slow out, snap to final value.
  23     ZERO,          // Returns a value of 0 always.
  24   };
  25
  26   // Returns the value based on the tween type. |state| is from 0-1.
  27   static double CalculateValue(Type type, double state);
  28
  29   // Conveniences for getting a value between a start and end point.
  30   static double ValueBetween(double value, double start, double target);
  31   static int ValueBetween(double value, int start, int target);
  32   static gfx::Rect ValueBetween(double value,
  33                                 const gfx::Rect& start_bounds,
  34                                 const gfx::Rect& target_bounds);
  35
  36  private:
  37   Tween();
  38   ~Tween();
  39
  40   DISALLOW_COPY_AND_ASSIGN(Tween);
  41 };
  42
  43 #endif  // APP_TWEEN_H_