Add DesktopFrame rotation functions

webrtc/modules/desktop_capture/desktop_frame_rotator.h

Index: webrtc/modules/desktop_capture/desktop_frame_rotator.h
diff --git a/webrtc/modules/desktop_capture/desktop_frame_rotator.h b/webrtc/modules/desktop_capture/desktop_frame_rotator.h
new file mode 100644
index 0000000000000000000000000000000000000000..3ac31dfa60eac744dac9c8983a765c306fdadb0b
--- /dev/null
+++ b/webrtc/modules/desktop_capture/desktop_frame_rotator.h
@@ -0,0 +1,47 @@
+/*
+ *  Copyright (c) 2016 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_ROTATOR_H_
+#define WEBRTC_MODULES_DESKTOP_CAPTURE_DESKTOP_FRAME_ROTATOR_H_
+
+#include "webrtc/modules/desktop_capture/desktop_frame.h"
+#include "webrtc/modules/desktop_capture/desktop_geometry.h"
+
+namespace webrtc {
+
+// Represents the rotation of a DesktopFrame.
+enum class Rotation {
+  CLOCK_WISE_0,
+  CLOCK_WISE_90,
+  CLOCK_WISE_180,
+  CLOCK_WISE_270,
+};
+
+// Rotates input DesktopFrame |src|, copies pixel in a rotated rectangle |rect|
+// into another DesktopFrame |target|, and adds |rect| into
+// |target|->mutable_updated_region(). Returns false if |target| is nullptr or
+// it does not cover the |rect|.
+bool CopyRotatedRectTo(const DesktopFrame& src,

[Sergey Ulanov, 2016/11/15 02:28:10]

It's better to use libyuv::ARGBRotate() instead of reimplementing that
functionality here. libyuv is optimized with SSE and so it should be
significanlty faster.

[Hzj_jie, 2016/11/15 05:17:03]

That's too bad, I have not found this function. I will test its performance.

Yes, libyuv::ARGBRotate() is 1x faster than the original C version. So I use it
in the implementation.

+                       DesktopRect rect,
+                       Rotation rotation,
+                       DesktopFrame* target);
+
+// Rotates input DesktopFrame |src|, copies pixel in a unrotated rectangle
+// |rect| into another DesktopFrame |target|, and adds rotated |rect| into
+// |target|->mutable_updated_region(). Returns false if |target| is nullptr or
+// it does not cover the |rect|.
+bool CopyUnrotatedRectTo(const DesktopFrame& src,
+                         DesktopRect rect,
+                         Rotation rotation,
+                         DesktopFrame* target);
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_DESKTOP_FRAME_ROTATOR_H_