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      1 // Copyright (c) 2011 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_ANIMATION_CONTAINER_H_
      6 #define UI_GFX_ANIMATION_ANIMATION_CONTAINER_H_
      7 
      8 #include <set>
      9 
     10 #include "base/memory/ref_counted.h"
     11 #include "base/time/time.h"
     12 #include "base/timer/timer.h"
     13 #include "ui/gfx/gfx_export.h"
     14 
     15 namespace gfx {
     16 
     17 class AnimationContainerElement;
     18 class AnimationContainerObserver;
     19 
     20 // AnimationContainer is used by Animation to manage the underlying timer.
     21 // Internally each Animation creates a single AnimationContainer. You can
     22 // group a set of Animations into the same AnimationContainer by way of
     23 // Animation::SetContainer. Grouping a set of Animations into the same
     24 // AnimationContainer ensures they all update and start at the same time.
     25 //
     26 // AnimationContainer is ref counted. Each Animation contained within the
     27 // AnimationContainer own it.
     28 class GFX_EXPORT AnimationContainer
     29     : public base::RefCounted<AnimationContainer> {
     30  public:
     31   AnimationContainer();
     32 
     33   // Invoked by Animation when it needs to start. Starts the timer if necessary.
     34   // NOTE: This is invoked by Animation for you, you shouldn't invoke this
     35   // directly.
     36   void Start(AnimationContainerElement* animation);
     37 
     38   // Invoked by Animation when it needs to stop. If there are no more animations
     39   // running the timer stops.
     40   // NOTE: This is invoked by Animation for you, you shouldn't invoke this
     41   // directly.
     42   void Stop(AnimationContainerElement* animation);
     43 
     44   void set_observer(AnimationContainerObserver* observer) {
     45     observer_ = observer;
     46   }
     47 
     48   // The time the last animation ran at.
     49   base::TimeTicks last_tick_time() const { return last_tick_time_; }
     50 
     51   // Are there any timers running?
     52   bool is_running() const { return !elements_.empty(); }
     53 
     54  private:
     55   friend class base::RefCounted<AnimationContainer>;
     56 
     57   typedef std::set<AnimationContainerElement*> Elements;
     58 
     59   ~AnimationContainer();
     60 
     61   // Timer callback method.
     62   void Run();
     63 
     64   // Sets min_timer_interval_ and restarts the timer.
     65   void SetMinTimerInterval(base::TimeDelta delta);
     66 
     67   // Returns the min timer interval of all the timers.
     68   base::TimeDelta GetMinInterval();
     69 
     70   // Represents one of two possible values:
     71   // . If only a single animation has been started and the timer hasn't yet
     72   //   fired this is the time the animation was added.
     73   // . The time the last animation ran at (::Run was invoked).
     74   base::TimeTicks last_tick_time_;
     75 
     76   // Set of elements (animations) being managed.
     77   Elements elements_;
     78 
     79   // Minimum interval the timers run at.
     80   base::TimeDelta min_timer_interval_;
     81 
     82   base::RepeatingTimer<AnimationContainer> timer_;
     83 
     84   AnimationContainerObserver* observer_;
     85 
     86   DISALLOW_COPY_AND_ASSIGN(AnimationContainer);
     87 };
     88 
     89 }  // namespace gfx
     90 
     91 #endif  // UI_GFX_ANIMATION_ANIMATION_CONTAINER_H_
     92