modules/desktop_capture/cropped_desktop_frame.cc

/*
 *  Copyright (c) 2014 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.
 */

#include <memory>

#include "webrtc/modules/desktop_capture/cropped_desktop_frame.h"

#include "webrtc/rtc_base/checks.h"
#include "webrtc/rtc_base/constructormagic.h"

namespace webrtc {

namespace {

DesktopRect TranslateRect(const DesktopRect& rect,
                          const DesktopVector& top_left) {
  DesktopRect result = rect;
  result.Translate(top_left);
  return result;
}

}  // namespace

// A DesktopFrame that is a sub-rect of another DesktopFrame.
class CroppedDesktopFrame : public DesktopFrame {
 public:
  CroppedDesktopFrame(std::unique_ptr<DesktopFrame> frame,
                      const DesktopRect& rect);

 private:
  std::unique_ptr<DesktopFrame> frame_;

  RTC_DISALLOW_COPY_AND_ASSIGN(CroppedDesktopFrame);
};

std::unique_ptr<DesktopFrame> CreateCroppedDesktopFrame(
    std::unique_ptr<DesktopFrame> frame,
    const DesktopRect& rect) {
  RTC_DCHECK(frame);

  if (!DesktopRect::MakeSize(frame->size()).ContainsRect(rect)) {
    return nullptr;
  }

  if (frame->size().equals(rect.size())) {
    return frame;
  }

  return std::unique_ptr<DesktopFrame>(
      new CroppedDesktopFrame(std::move(frame), rect));
}

CroppedDesktopFrame::CroppedDesktopFrame(std::unique_ptr<DesktopFrame> frame,
                                         const DesktopRect& rect)
    : DesktopFrame(TranslateRect(rect, frame->top_left()),
                   frame->stride(),
                   frame->GetFrameDataAtPos(rect.top_left()),
                   frame->shared_memory()) {
  frame_ = std::move(frame);
}

}  // namespace webrtc