sergeyu@chromium.org | 6c82a7e | 2013-06-04 18:51:23 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2013 The WebRTC project authors. All Rights Reserved. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license |
| 5 | * that can be found in the LICENSE file in the root of the source |
| 6 | * tree. An additional intellectual property rights grant can be found |
| 7 | * in the file PATENTS. All contributing project authors may |
| 8 | * be found in the AUTHORS file in the root of the source tree. |
| 9 | */ |
| 10 | |
| 11 | #ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_SCREEN_CAPTURER_HELPER_H_ |
| 12 | #define WEBRTC_MODULES_DESKTOP_CAPTURE_SCREEN_CAPTURER_HELPER_H_ |
| 13 | |
| 14 | #include "webrtc/modules/desktop_capture/desktop_geometry.h" |
| 15 | #include "webrtc/modules/desktop_capture/desktop_region.h" |
| 16 | #include "webrtc/system_wrappers/interface/rw_lock_wrapper.h" |
| 17 | #include "webrtc/system_wrappers/interface/scoped_ptr.h" |
| 18 | |
| 19 | namespace webrtc { |
| 20 | |
| 21 | // ScreenCapturerHelper is intended to be used by an implementation of the |
| 22 | // ScreenCapturer interface. It maintains a thread-safe invalid region, and |
| 23 | // the size of the most recently captured screen, on behalf of the |
| 24 | // ScreenCapturer that owns it. |
| 25 | class ScreenCapturerHelper { |
| 26 | public: |
| 27 | ScreenCapturerHelper(); |
| 28 | ~ScreenCapturerHelper(); |
| 29 | |
| 30 | // Clear out the invalid region. |
| 31 | void ClearInvalidRegion(); |
| 32 | |
| 33 | // Invalidate the specified region. |
| 34 | void InvalidateRegion(const DesktopRegion& invalid_region); |
| 35 | |
| 36 | // Invalidate the entire screen, of a given size. |
| 37 | void InvalidateScreen(const DesktopSize& size); |
| 38 | |
| 39 | // Copies current invalid region to |invalid_region| clears invalid region |
| 40 | // storage for the next frame. |
| 41 | void TakeInvalidRegion(DesktopRegion* invalid_region); |
| 42 | |
| 43 | // Access the size of the most recently captured screen. |
| 44 | const DesktopSize& size_most_recent() const; |
| 45 | void set_size_most_recent(const DesktopSize& size); |
| 46 | |
| 47 | // Lossy compression can result in color values leaking between pixels in one |
| 48 | // block. If part of a block changes, then unchanged parts of that block can |
| 49 | // be changed in the compressed output. So we need to re-render an entire |
| 50 | // block whenever part of the block changes. |
| 51 | // |
| 52 | // If |log_grid_size| is >= 1, then this function makes TakeInvalidRegion() |
| 53 | // produce an invalid region expanded so that its vertices lie on a grid of |
| 54 | // size 2 ^ |log_grid_size|. The expanded region is then clipped to the size |
| 55 | // of the most recently captured screen, as previously set by |
| 56 | // set_size_most_recent(). |
| 57 | // If |log_grid_size| is <= 0, then the invalid region is not expanded. |
| 58 | void SetLogGridSize(int log_grid_size); |
| 59 | |
| 60 | // Expands a region so that its vertices all lie on a grid. |
| 61 | // The grid size must be >= 2, so |log_grid_size| must be >= 1. |
| 62 | static void ExpandToGrid(const DesktopRegion& region, |
| 63 | int log_grid_size, |
| 64 | DesktopRegion* result); |
| 65 | |
| 66 | private: |
| 67 | // A region that has been manually invalidated (through InvalidateRegion). |
| 68 | // These will be returned as dirty_region in the capture data during the next |
| 69 | // capture. |
| 70 | DesktopRegion invalid_region_; |
| 71 | |
| 72 | // A lock protecting |invalid_region_| across threads. |
| 73 | scoped_ptr<RWLockWrapper> invalid_region_lock_; |
| 74 | |
| 75 | // The size of the most recently captured screen. |
| 76 | DesktopSize size_most_recent_; |
| 77 | |
| 78 | // The log (base 2) of the size of the grid to which the invalid region is |
| 79 | // expanded. |
| 80 | // If the value is <= 0, then the invalid region is not expanded to a grid. |
| 81 | int log_grid_size_; |
| 82 | |
| 83 | DISALLOW_COPY_AND_ASSIGN(ScreenCapturerHelper); |
| 84 | }; |
| 85 | |
| 86 | } // namespace webrtc |
| 87 | |
| 88 | #endif // WEBRTC_MODULES_DESKTOP_CAPTURE_SCREEN_CAPTURER_HELPER_H_ |