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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 REMOTING_HOST_VIDEO_FRAME_CAPTURER_HELPER_H_ | |
| 6 #define REMOTING_HOST_VIDEO_FRAME_CAPTURER_HELPER_H_ | |
| 7 | |
| 8 #include "base/memory/scoped_ptr.h" | |
| 9 #include "base/synchronization/lock.h" | |
| 10 #include "third_party/skia/include/core/SkRegion.h" | |
| 11 | |
| 12 namespace remoting { | |
| 13 | |
| 14 // VideoFrameCapturerHelper is intended to be used by an implementation of the | |
| 15 // VideoFrameCapturer interface. It maintains a thread-safe invalid region, and | |
| 16 // the size of the most recently captured screen, on behalf of the | |
| 17 // VideoFrameCapturer that owns it. | |
| 18 class VideoFrameCapturerHelper { | |
| 19 public: | |
| 20 VideoFrameCapturerHelper(); | |
| 21 ~VideoFrameCapturerHelper(); | |
| 22 | |
| 23 // Clear out the invalid region. | |
| 24 void ClearInvalidRegion(); | |
| 25 | |
| 26 // Invalidate the specified region. | |
| 27 void InvalidateRegion(const SkRegion& invalid_region); | |
| 28 | |
| 29 // Invalidate the entire screen, of a given size. | |
| 30 void InvalidateScreen(const SkISize& size); | |
| 31 | |
| 32 // Invalidate the entire screen, using the size of the most recently | |
| 33 // captured screen. | |
| 34 void InvalidateFullScreen(); | |
| 35 | |
| 36 // Swap the given region with the stored invalid region. | |
| 37 void SwapInvalidRegion(SkRegion* invalid_region); | |
| 38 | |
| 39 // Access the size of the most recently captured screen. | |
| 40 const SkISize& size_most_recent() const; | |
| 41 void set_size_most_recent(const SkISize& 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 SwapInvalidRegion | |
| 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 SkISize 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(VideoFrameCapturerHelper); | |
| 79 }; | |
| 80 | |
| 81 } // namespace remoting | |
| 82 | |
| 83 #endif // REMOTING_HOST_VIDEO_FRAME_CAPTURER_HELPER_H_ | |
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