Add DesktopFrame rotation functions

webrtc/modules/desktop_capture/desktop_frame_rotator.cc

+/*
+ *  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.
+ */
+
+#include "webrtc/modules/desktop_capture/desktop_frame_rotator.h"
+
+#include <string.h>
+
+#include "webrtc/base/checks.h"
+
+#include "third_party/libyuv/include/libyuv/rotate_argb.h"
+
+namespace webrtc {
+
+namespace {
+
+// Returns a rotated DesktopRect of |rect|. The |size| represents the size of
+// the DesktopFrame which |rect| belongs in.
+DesktopRect RotateRect(DesktopRect rect, DesktopSize size, Rotation rotation) {
+  switch (rotation) {
+    case Rotation::CLOCK_WISE_0:
+      return rect;
+    case Rotation::CLOCK_WISE_90:
+      return DesktopRect::MakeLTRB(size.height() - rect.bottom(), rect.left(),

[Sergey Ulanov, 2016/11/17 02:07:39]

MakeXYWH() here for consistency.

[Hzj_jie, 2016/11/17 07:14:55]

Done.

+                                   size.height() - rect.top(), rect.right());
+    case Rotation::CLOCK_WISE_180:
+      return DesktopRect::MakeXYWH(size.width() - rect.right(),
+                                   size.height() - rect.bottom(), rect.width(),
+                                   rect.height());
+    case Rotation::CLOCK_WISE_270:
+      return DesktopRect::MakeLTRB(rect.top(), size.width() - rect.right(),

[Sergey Ulanov, 2016/11/17 02:07:39]

MakeXYWH()?

[Hzj_jie, 2016/11/17 07:14:55]

Done.

+                                   rect.bottom(), size.width() - rect.left());
+  }
+  RTC_NOTREACHED();
+  return DesktopRect();
+}
+
+// Returns a reverse-rotated Rotation of |rotation|.
+Rotation Reverse(Rotation rotation) {
+  switch (rotation) {
+    case Rotation::CLOCK_WISE_0:
+      return rotation;
+    case Rotation::CLOCK_WISE_90:
+      return Rotation::CLOCK_WISE_270;
+    case Rotation::CLOCK_WISE_180:
+      return Rotation::CLOCK_WISE_180;
+    case Rotation::CLOCK_WISE_270:
+      return Rotation::CLOCK_WISE_90;
+  }
+  RTC_NOTREACHED();
+  return Rotation::CLOCK_WISE_0;
+}
+
+// Returns a rotated DesktopSize of |size|.
+DesktopSize GetRotatedSize(DesktopSize size, Rotation rotation) {
+  switch (rotation) {
+    case Rotation::CLOCK_WISE_0:
+    case Rotation::CLOCK_WISE_180:
+      return size;
+    case Rotation::CLOCK_WISE_90:
+    case Rotation::CLOCK_WISE_270:
+      return DesktopSize(size.height(), size.width());
+    default:

[Sergey Ulanov, 2016/11/17 02:07:38]

Please remove default case.

[Hzj_jie, 2016/11/17 07:14:55]

Done.

+      RTC_NOTREACHED();
+      return DesktopSize();
+  }
+}
+
+libyuv::RotationMode ToLibyuvRotationMode(Rotation rotation) {
+  switch (rotation) {
+    case Rotation::CLOCK_WISE_0:
+      return libyuv::kRotate0;
+    case Rotation::CLOCK_WISE_90:
+      return libyuv::kRotate90;
+    case Rotation::CLOCK_WISE_180:
+      return libyuv::kRotate180;
+    case Rotation::CLOCK_WISE_270:
+      return libyuv::kRotate270;
+    default:

[Sergey Ulanov, 2016/11/17 02:07:39]

Don't need this.

[Hzj_jie, 2016/11/17 07:14:55]

Done.

+      RTC_NOTREACHED();
+      return libyuv::kRotate0;
+  }
+}
+
+}  // namespace
+
+bool CopyRotatedRectTo(const DesktopFrame& source,

[Sergey Ulanov, 2016/11/17 02:07:39]

Do we really need to return any result from this function? It may fail only if
the caller passes incorrectly-sized frame or rect, but then it should be be
DCHECK'ed instead of returning an error.

[Hzj_jie, 2016/11/17 07:14:55]

Done.

+                       DesktopRect rect,
+                       Rotation rotation,
+                       DesktopFrame* target) {
+  RTC_DCHECK(target);
+  if (!DesktopRect::MakeSize(target->size()).ContainsRect(rect)) {

[Sergey Ulanov, 2016/11/17 02:07:39]

Replace this with DCHECK?

[Hzj_jie, 2016/11/17 07:14:55]

Done.

+    return false;
+  }
+  if (rect.is_empty()) {
+    return true;
+  }
+
+  target->mutable_updated_region()->AddRect(rect);
+  // The rectangle in |source|.
+  const DesktopRect source_rect =
+      RotateRect(rect, GetRotatedSize(source.size(), Reverse(rotation)),

[Sergey Ulanov, 2016/11/17 02:07:39]

Don't need really need to reverse rotation for GetRotatedSize() (because
GetRotatedSize(r) is always the same as GetRotatedSize(Reverse(rotation)) ), but
if you do then cache the result to avoid calling Reverse() twice.

[Hzj_jie, 2016/11/17 07:14:55]

Yes, I know they are same. But I think Reverse(rotation) here make the logic
look clearer, as reader does not need to consider to understand the correctness
of this line.
I will cache the result of Reverse(rotation).

+                 Reverse(rotation));
+  return libyuv::ARGBRotate(
+             source.GetFrameDataAtPos(source_rect.top_left()), source.stride(),
+             target->GetFrameDataAtPos(rect.top_left()), target->stride(),
+             source_rect.width(), source_rect.height(),
+             ToLibyuvRotationMode(rotation)) == 0;
+}
+
+bool CopyUnrotatedRectTo(const DesktopFrame& source,
+                         DesktopRect rect,
+                         Rotation rotation,
+                         DesktopFrame* target) {
+  return CopyRotatedRectTo(source, RotateRect(rect, source.size(), rotation),
+                           rotation, target);
+}
+
+}  // namespace webrtc