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| 1 // Copyright 2014 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_COMPOSITOR_COMPOSITOR_VSYNC_MANAGER_H_ |
| 6 #define UI_COMPOSITOR_COMPOSITOR_VSYNC_MANAGER_H_ |
| 7 |
| 8 #include "base/memory/ref_counted.h" |
| 9 #include "base/observer_list.h" |
| 10 #include "base/synchronization/lock.h" |
| 11 #include "base/time/time.h" |
| 12 #include "ui/compositor/compositor_export.h" |
| 13 |
| 14 namespace ui { |
| 15 |
| 16 // This class manages vsync parameters for a compositor. It merges updates of |
| 17 // the parameters from different sources and sends the merged updates to |
| 18 // observers which register to it. |
| 19 class COMPOSITOR_EXPORT CompositorVSyncManager |
| 20 : public base::RefCounted<CompositorVSyncManager> { |
| 21 public: |
| 22 class Observer { |
| 23 public: |
| 24 virtual void OnUpdateVSyncParameters(base::TimeTicks timebase, |
| 25 base::TimeDelta interval) = 0; |
| 26 }; |
| 27 |
| 28 CompositorVSyncManager(); |
| 29 |
| 30 // The "authoritative" vsync interval, if provided, will override |interval| |
| 31 // as reported by UpdateVSyncParameters() whenever it is called. This is |
| 32 // typically the value reported by a more reliable source, e.g. the platform |
| 33 // display configuration. In the particular case of ChromeOS -- this is the |
| 34 // value queried through XRandR, which is more reliable than the value |
| 35 // queried through the 3D context. |
| 36 void SetAuthoritativeVSyncInterval(base::TimeDelta interval); |
| 37 |
| 38 // The vsync parameters consist of |timebase|, which is the platform timestamp |
| 39 // of the last vsync, and |interval|, which is the interval between vsyncs. |
| 40 // |interval| may be overriden by SetAuthoritativeVSyncInterval() above. |
| 41 void UpdateVSyncParameters(base::TimeTicks timebase, |
| 42 base::TimeDelta interval); |
| 43 |
| 44 void AddObserver(Observer* observer); |
| 45 void RemoveObserver(Observer* observer); |
| 46 |
| 47 private: |
| 48 friend class base::RefCounted<CompositorVSyncManager>; |
| 49 |
| 50 ~CompositorVSyncManager(); |
| 51 |
| 52 void NotifyObservers(base::TimeTicks timebase, base::TimeDelta interval); |
| 53 |
| 54 ObserverList<Observer> observer_list_; |
| 55 |
| 56 base::TimeTicks last_timebase_; |
| 57 base::TimeDelta last_interval_; |
| 58 base::TimeDelta authoritative_vsync_interval_; |
| 59 |
| 60 DISALLOW_COPY_AND_ASSIGN(CompositorVSyncManager); |
| 61 }; |
| 62 |
| 63 } // namespace ui |
| 64 |
| 65 #endif // UI_COMPOSITOR_COMPOSITOR_VSYNC_MANAGER_H_ |
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