webrtc/modules/desktop_capture/desktop_frame.h

/*
 *  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 WEBRTC_MODULES_DESKTOP_CAPTURE_DESKTOP_FRAME_H_
#define WEBRTC_MODULES_DESKTOP_CAPTURE_DESKTOP_FRAME_H_

#include "webrtc/modules/desktop_capture/desktop_geometry.h"
#include "webrtc/modules/desktop_capture/desktop_region.h"
#include "webrtc/modules/desktop_capture/shared_memory.h"
#include "webrtc/typedefs.h"

namespace webrtc {

// DesktopFrame represents a video frame captured from the screen.
class DesktopFrame {
 public:
  // DesktopFrame objects always hold RGBA data.
  static const int kBytesPerPixel = 4;

  virtual ~DesktopFrame();

  // Size of the frame.
  const DesktopSize& size() const { return size_; }

  // Distance in the buffer between two neighboring rows in bytes.
  int stride() const { return stride_; }

  // Data buffer used for the frame.
  uint8_t* data() const { return data_; }

  // SharedMemory used for the buffer or NULL if memory is allocated on the
  // heap. The result is guaranteed to be deleted only after the frame is
  // deleted (classes that inherit from DesktopFrame must ensure it).
  SharedMemory* shared_memory() const { return shared_memory_; }

  // Indicates region of the screen that has changed since the previous frame.
  const DesktopRegion& updated_region() const { return updated_region_; }
  DesktopRegion* mutable_updated_region() { return &updated_region_; }

  // DPI of the screen being captured. May be set to zero, e.g. if DPI is
  // unknown.
  const DesktopVector& dpi() const { return dpi_; }
  void set_dpi(const DesktopVector& dpi) { dpi_ = dpi; }

  // Time taken to capture the frame in milliseconds.
  int32_t capture_time_ms() const { return capture_time_ms_; }
  void set_capture_time_ms(int32_t time_ms) { capture_time_ms_ = time_ms; }

 protected:
  DesktopFrame(DesktopSize size,
               int stride,
               uint8_t* data,
               SharedMemory* shared_memory);

  const DesktopSize size_;
  const int stride_;

  // Ownership of the buffers is defined by the classes that inherit from this
  // class. They must guarantee that the buffer is not deleted before the frame
  // is deleted.
  uint8_t* const data_;
  SharedMemory* const shared_memory_;

  DesktopRegion updated_region_;

  DesktopVector dpi_;
  int32_t capture_time_ms_;

 private:
  DISALLOW_COPY_AND_ASSIGN(DesktopFrame);
};

// A DesktopFrame that stores data in the heap.
class BasicDesktopFrame : public DesktopFrame {
 public:
  explicit BasicDesktopFrame(DesktopSize size);
  virtual ~BasicDesktopFrame();

  // Creates a BasicDesktopFrame that contains copy of |frame|.
  static DesktopFrame* CopyOf(const DesktopFrame& frame);

 private:
  DISALLOW_COPY_AND_ASSIGN(BasicDesktopFrame);
};

// A DesktopFrame that stores data in shared memory.
class SharedMemoryDesktopFrame : public DesktopFrame {
 public:
  // Takes ownership of |shared_memory|.
  SharedMemoryDesktopFrame(DesktopSize size,
                           int stride,
                           SharedMemory* shared_memory);
  virtual ~SharedMemoryDesktopFrame();

 private:
  DISALLOW_COPY_AND_ASSIGN(SharedMemoryDesktopFrame);
};

}  // namespace webrtc

#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_DESKTOP_FRAME_H_