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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 MEDIA_VIDEO_CAPTURE_SCREEN_SCREEN_CAPTURER_HELPER_H_ | |
6 #define MEDIA_VIDEO_CAPTURE_SCREEN_SCREEN_CAPTURER_HELPER_H_ | |
7 | |
8 #include "base/memory/scoped_ptr.h" | |
9 #include "base/synchronization/lock.h" | |
10 #include "media/base/media_export.h" | |
11 #include "third_party/skia/include/core/SkRegion.h" | |
12 #include "third_party/webrtc/modules/desktop_capture/desktop_geometry.h" | |
13 #include "third_party/webrtc/modules/desktop_capture/desktop_region.h" | |
14 | |
15 namespace media { | |
16 | |
17 // ScreenCapturerHelper is intended to be used by an implementation of the | |
18 // ScreenCapturer interface. It maintains a thread-safe invalid region, and | |
19 // the size of the most recently captured screen, on behalf of the | |
20 // ScreenCapturer that owns it. | |
21 class MEDIA_EXPORT ScreenCapturerHelper { | |
22 public: | |
23 ScreenCapturerHelper(); | |
24 ~ScreenCapturerHelper(); | |
25 | |
26 // Clear out the invalid region. | |
27 void ClearInvalidRegion(); | |
28 | |
29 // Invalidate the specified region. | |
30 void InvalidateRegion(const webrtc::DesktopRegion& invalid_region); | |
31 | |
32 // Invalidate the entire screen, of a given size. | |
33 void InvalidateScreen(const webrtc::DesktopSize& size); | |
34 | |
35 // Copies current invalid region to |invalid_region| clears invalid region | |
36 // storage for the next frame. | |
37 void TakeInvalidRegion(webrtc::DesktopRegion* invalid_region); | |
38 | |
39 // Access the size of the most recently captured screen. | |
40 const webrtc::DesktopSize& size_most_recent() const; | |
41 void set_size_most_recent(const webrtc::DesktopSize& size); | |
42 | |
43 // Lossy compression can result in color values leaking between pixels in one | |
44 // block. If part of a block changes, then unchanged parts of that block can | |
45 // be changed in the compressed output. So we need to re-render an entire | |
46 // block whenever part of the block changes. | |
47 // | |
48 // If |log_grid_size| is >= 1, then this function makes TakeInvalidRegion() | |
49 // produce an invalid region expanded so that its vertices lie on a grid of | |
50 // size 2 ^ |log_grid_size|. The expanded region is then clipped to the size | |
51 // of the most recently captured screen, as previously set by | |
52 // set_size_most_recent(). | |
53 // If |log_grid_size| is <= 0, then the invalid region is not expanded. | |
54 void SetLogGridSize(int log_grid_size); | |
55 | |
56 // Expands a region so that its vertices all lie on a grid. | |
57 // The grid size must be >= 2, so |log_grid_size| must be >= 1. | |
58 static scoped_ptr<SkRegion> ExpandToGrid(const SkRegion& region, | |
59 int log_grid_size); | |
60 | |
61 private: | |
62 // A region that has been manually invalidated (through InvalidateRegion). | |
63 // These will be returned as dirty_region in the capture data during the next | |
64 // capture. | |
65 SkRegion invalid_region_; | |
66 | |
67 // A lock protecting |invalid_region_| across threads. | |
68 base::Lock invalid_region_lock_; | |
69 | |
70 // The size of the most recently captured screen. | |
71 webrtc::DesktopSize size_most_recent_; | |
72 | |
73 // The log (base 2) of the size of the grid to which the invalid region is | |
74 // expanded. | |
75 // If the value is <= 0, then the invalid region is not expanded to a grid. | |
76 int log_grid_size_; | |
77 | |
78 DISALLOW_COPY_AND_ASSIGN(ScreenCapturerHelper); | |
79 }; | |
80 | |
81 } // namespace media | |
82 | |
83 #endif // MEDIA_VIDEO_CAPTURE_SCREEN_SCREEN_CAPTURER_HELPER_H_ | |
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