1// Copyright (c) 2012 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_OBSERVER_H_
6#define UI_COMPOSITOR_COMPOSITOR_OBSERVER_H_
7
8#include "base/time/time.h"
9#include "ui/compositor/compositor_export.h"
10
11namespace ui {
12
13class Compositor;
14
15// A compositor observer is notified when compositing completes.
16class COMPOSITOR_EXPORT CompositorObserver {
17 public:
18  CompositorObserver();
19
20  // A commit proxies information from the main thread to the compositor
21  // thread. It typically happens when some state changes that will require a
22  // composite. In the multi-threaded case, many commits may happen between
23  // two successive composites. In the single-threaded, a single commit
24  // between two composites (just before the composite as part of the
25  // composite cycle). If the compositor is locked, it will not send this
26  // this signal.
27  virtual void OnCompositingDidCommit(Compositor* compositor) = 0;
28
29  // Called when compositing started: it has taken all the layer changes into
30  // account and has issued the graphics commands.
31  virtual void OnCompositingStarted(Compositor* compositor,
32                                    base::TimeTicks start_time) = 0;
33
34  // Called when compositing completes: the present to screen has completed.
35  virtual void OnCompositingEnded(Compositor* compositor) = 0;
36
37  // Called when compositing is aborted (e.g. lost graphics context).
38  virtual void OnCompositingAborted(Compositor* compositor) = 0;
39
40  // Called when the compositor lock state changes.
41  virtual void OnCompositingLockStateChanged(Compositor* compositor) = 0;
42
43 protected:
44#if defined(OS_MACOSX)
45  // Debugging instrumentation for crbug.com/401630.
46  // TODO(ccameron): remove this.
47  friend class Compositor;
48  int32 observing_count_;
49#endif
50
51  virtual ~CompositorObserver();
52};
53
54}  // namespace ui
55
56#endif  // UI_COMPOSITOR_COMPOSITOR_OBSERVER_H_
57