screen_capturer_helper.h

Enable keyboard shortcuts

/*

 *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.

 *  Use of this source code is governed by a BSD-style license

 *  that can be found in the LICENSE file in the root of the source

 *  tree. An additional intellectual property rights grant can be found

 *  in the file PATENTS.  All contributing project authors may

 *  be found in the AUTHORS file in the root of the source tree.

*/

#ifndef MODULES_DESKTOP_CAPTURE_SCREEN_CAPTURER_HELPER_H_

#define MODULES_DESKTOP_CAPTURE_SCREEN_CAPTURER_HELPER_H_

#include <memory>

#include "modules/desktop_capture/desktop_geometry.h"

#include "modules/desktop_capture/desktop_region.h"

#include "rtc_base/synchronization/mutex.h"

#include "rtc_base/thread_annotations.h"

namespace webrtc {

// ScreenCapturerHelper is intended to be used by an implementation of the

// ScreenCapturer interface. It maintains a thread-safe invalid region, and

// the size of the most recently captured screen, on behalf of the

// ScreenCapturer that owns it.

class ScreenCapturerHelper {

 public:

  ScreenCapturerHelper() = default;

  ~ScreenCapturerHelper() = default;

  ScreenCapturerHelper(const ScreenCapturerHelper&) = delete;

  ScreenCapturerHelper& operator=(const ScreenCapturerHelper&) = delete;

  // Clear out the invalid region.

  void ClearInvalidRegion();

  // Invalidate the specified region.

  void InvalidateRegion(const DesktopRegion& invalid_region);

  // Invalidate the entire screen, of a given size.

  void InvalidateScreen(const DesktopSize& size);

  // Copies current invalid region to `invalid_region` clears invalid region

  // storage for the next frame.

  void TakeInvalidRegion(DesktopRegion* invalid_region);

  // Access the size of the most recently captured screen.

  const DesktopSize& size_most_recent() const;

  void set_size_most_recent(const DesktopSize& size);

  // Lossy compression can result in color values leaking between pixels in one

  // block. If part of a block changes, then unchanged parts of that block can

  // be changed in the compressed output. So we need to re-render an entire

  // block whenever part of the block changes.

//

  // If `log_grid_size` is >= 1, then this function makes TakeInvalidRegion()

  // produce an invalid region expanded so that its vertices lie on a grid of

  // size 2 ^ `log_grid_size`. The expanded region is then clipped to the size

  // of the most recently captured screen, as previously set by

  // set_size_most_recent().

  // If `log_grid_size` is <= 0, then the invalid region is not expanded.

  void SetLogGridSize(int log_grid_size);

  // Expands a region so that its vertices all lie on a grid.

  // The grid size must be >= 2, so `log_grid_size` must be >= 1.

  static void ExpandToGrid(const DesktopRegion& region,

                           int log_grid_size,

                           DesktopRegion* result);

 private:

  // A region that has been manually invalidated (through InvalidateRegion).

  // These will be returned as dirty_region in the capture data during the next

  // capture.

  DesktopRegion invalid_region_ RTC_GUARDED_BY(invalid_region_mutex_);

  // A lock protecting `invalid_region_` across threads.

  Mutex invalid_region_mutex_;

  // The size of the most recently captured screen.

  DesktopSize size_most_recent_;

  // The log (base 2) of the size of the grid to which the invalid region is

  // expanded.

  // If the value is <= 0, then the invalid region is not expanded to a grid.

  int log_grid_size_ = 0;

};

}  // namespace webrtc

#endif  // MODULES_DESKTOP_CAPTURE_SCREEN_CAPTURER_HELPER_H_