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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_DIFFER_H_ | |
6 #define MEDIA_VIDEO_CAPTURE_SCREEN_DIFFER_H_ | |
7 | |
8 #include <vector> | |
9 | |
10 #include "base/basictypes.h" | |
11 #include "base/memory/scoped_ptr.h" | |
12 #include "media/base/media_export.h" | |
13 #include "third_party/webrtc/modules/desktop_capture/desktop_region.h" | |
14 | |
15 namespace media { | |
16 | |
17 typedef uint8 DiffInfo; | |
18 | |
19 // TODO: Simplify differ now that we are working with webrtc::DesktopRegion. | |
20 // diff_info_ should no longer be needed, as we can put our data directly into | |
21 // the region that we are calculating. | |
22 // http://crbug.com/92379 | |
23 // TODO(sergeyu): Rename this class to something more sensible, e.g. | |
24 // ScreenCaptureFrameDifferencer. | |
25 class MEDIA_EXPORT Differ { | |
26 public: | |
27 // Create a differ that operates on bitmaps with the specified width, height | |
28 // and bytes_per_pixel. | |
29 Differ(int width, int height, int bytes_per_pixel, int stride); | |
30 ~Differ(); | |
31 | |
32 int width() { return width_; } | |
33 int height() { return height_; } | |
34 int bytes_per_pixel() { return bytes_per_pixel_; } | |
35 int bytes_per_row() { return bytes_per_row_; } | |
36 | |
37 // Given the previous and current screen buffer, calculate the dirty region | |
38 // that encloses all of the changed pixels in the new screen. | |
39 void CalcDirtyRegion(const void* prev_buffer, const void* curr_buffer, | |
40 webrtc::DesktopRegion* region); | |
41 | |
42 private: | |
43 // Allow tests to access our private parts. | |
44 friend class DifferTest; | |
45 | |
46 // Identify all of the blocks that contain changed pixels. | |
47 void MarkDirtyBlocks(const void* prev_buffer, const void* curr_buffer); | |
48 | |
49 // After the dirty blocks have been identified, this routine merges adjacent | |
50 // blocks into a region. | |
51 // The goal is to minimize the region that covers the dirty blocks. | |
52 void MergeBlocks(webrtc::DesktopRegion* region); | |
53 | |
54 // Check for diffs in upper-left portion of the block. The size of the portion | |
55 // to check is specified by the |width| and |height| values. | |
56 // Note that if we force the capturer to always return images whose width and | |
57 // height are multiples of kBlockSize, then this will never be called. | |
58 DiffInfo DiffPartialBlock(const uint8* prev_buffer, const uint8* curr_buffer, | |
59 int stride, int width, int height); | |
60 | |
61 // Dimensions of screen. | |
62 int width_; | |
63 int height_; | |
64 | |
65 // Number of bytes for each pixel in source and dest bitmap. | |
66 // (Yes, they must match.) | |
67 int bytes_per_pixel_; | |
68 | |
69 // Number of bytes in each row of the image (AKA: stride). | |
70 int bytes_per_row_; | |
71 | |
72 // Diff information for each block in the image. | |
73 scoped_ptr<DiffInfo[]> diff_info_; | |
74 | |
75 // Dimensions and total size of diff info array. | |
76 int diff_info_width_; | |
77 int diff_info_height_; | |
78 int diff_info_size_; | |
79 | |
80 DISALLOW_COPY_AND_ASSIGN(Differ); | |
81 }; | |
82 | |
83 } // namespace media | |
84 | |
85 #endif // MEDIA_VIDEO_CAPTURE_SCREEN_DIFFER_H_ | |
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