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