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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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