app/multi_animation.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_MULTI_ANIMATION_H_
   6 #define APP_MULTI_ANIMATION_H_
   7 #pragma once
   8
   9 #include <vector>
  10
  11 #include "app/animation.h"
  12 #include "app/tween.h"
  13
  14 // MultiAnimation is an animation that consists of a number of sub animations.
  15 // To create a MultiAnimation pass in the parts, invoke Start() and the delegate
  16 // is notified as the animation progresses. MultiAnimation runs until Stop is
  17 // invoked.
  18 class MultiAnimation : public Animation {
  19  public:
  20   // Defines part of the animation. Each part consists of the following:
  21   //
  22   // time_ms: the time of the part.
  23   // start_time_ms: the amount of time to offset this part by when calculating
  24   // the percented completed.
  25   // end_time_ms: the end time used to calculate the percentange completed.
  26   //
  27   // In most cases |start_time_ms| = 0 and |end_time_ms| = |time_ms|. But you
  28   // can adjust the start/end for different effects. For example, to run a part
  29   // for 200ms with a % between .25 and .75 use the following three values: 200,
  30   // 100, 400.
  31   struct Part {
  32     Part() : time_ms(0), start_time_ms(0), end_time_ms(0), type(Tween::ZERO) {}
  33     Part(int time_ms, Tween::Type type)
  34         : time_ms(time_ms),
  35           start_time_ms(0),
  36           end_time_ms(time_ms),
  37           type(type) {}
  38
  39     int time_ms;
  40     int start_time_ms;
  41     int end_time_ms;
  42     Tween::Type type;
  43   };
  44
  45   typedef std::vector<Part> Parts;
  46
  47   explicit MultiAnimation(const Parts& parts);
  48
  49   // Returns the current value. The current value for a MultiAnimation is
  50   // determined from the tween type of the current part.
  51   virtual double GetCurrentValue() const { return current_value_; }
  52
  53   // Returns the index of the current part.
  54   size_t current_part_index() const { return current_part_index_; }
  55
  56  protected:
  57   // Animation overrides.
  58   virtual void Step(base::TimeTicks time_now);
  59
  60  private:
  61   // Returns the part containing the specified time. |time_ms| is reset to be
  62   // relative to the part containing the time and |part_index| the index of the
  63   // part.
  64   const Part& GetPart(int* time_ms, size_t* part_index);
  65
  66   // The parts that make up the animation.
  67   const Parts parts_;
  68
  69   // Total time of all the parts.
  70   const int cycle_time_ms_;
  71
  72   // Current value for the animation.
  73   double current_value_;
  74
  75   // Index of the current part.
  76   size_t current_part_index_;
  77
  78   DISALLOW_COPY_AND_ASSIGN(MultiAnimation);
  79 };
  80
  81 #endif  // APP_MULTI_ANIMATION_H_