Introducing a helper wrapper for YUV-to-RGB convertion and/or scaling.

remoting/base/util.cc

Index: remoting/base/util.cc
diff --git a/remoting/base/util.cc b/remoting/base/util.cc
index 486b6a3510e6f42efa1680d449d7363628aa4b14..30691ea065531f9300883092de8dc55d5316b65b 100644
--- a/remoting/base/util.cc
+++ b/remoting/base/util.cc
@@ -11,6 +11,7 @@
 #include "base/time.h"
 #include "media/base/video_frame.h"
 #include "media/base/yuv_convert.h"
+#include "third_party/skia/include/core/SkRegion.h"
 
 using media::VideoFrame;
 
@@ -48,38 +49,15 @@ static int CalculateRGBOffset(int x, int y, int stride) {
 }
 
 static int CalculateYOffset(int x, int y, int stride) {
+  DCHECK(((x & 1) == 0) && ((y & 1) == 0));
   return stride * y + x;
 }
 
 static int CalculateUVOffset(int x, int y, int stride) {
+  DCHECK(((x & 1) == 0) && ((y & 1) == 0));
   return stride * y / 2 + x / 2;
 }
 
-void ConvertYUVToRGB32WithRect(const uint8* y_plane,
-                               const uint8* u_plane,
-                               const uint8* v_plane,
-                               uint8* rgb_plane,
-                               const SkIRect& rect,
-                               int y_stride,
-                               int uv_stride,
-                               int rgb_stride) {
-  DCHECK((rect.x() & 1) == 0 && (rect.y() & 1) == 0);
-  int rgb_offset = CalculateRGBOffset(rect.left(), rect.top(), rgb_stride);
-  int y_offset = CalculateYOffset(rect.left(), rect.top(), y_stride);
-  int uv_offset = CalculateUVOffset(rect.left(), rect.top(), uv_stride);
-
-  media::ConvertYUVToRGB32(y_plane + y_offset,
-                           u_plane + uv_offset,
-                           v_plane + uv_offset,
-                           rgb_plane + rgb_offset,
-                           rect.width(),
-                           rect.height(),
-                           y_stride,
-                           uv_stride,
-                           rgb_stride,
-                           media::YV12);
-}
-
 void ConvertRGB32ToYUVWithRect(const uint8* rgb_plane,
                                uint8* y_plane,
                                uint8* u_plane,
@@ -106,6 +84,126 @@ void ConvertRGB32ToYUVWithRect(const uint8* rgb_plane,
                            uv_stride);
 }
 
+void ConvertAndScaleYUVToRGB32Rect(const uint8* source_yplane,
+                                   const uint8* source_uplane,
+                                   const uint8* source_vplane,
+                                   int source_ystride,
+                                   int source_uvstride,
+                                   const SkISize& source_size,
+                                   const SkIRect& source_buffer_rect,
+                                   uint8* dest_buffer,
+                                   int dest_stride,
+                                   const SkISize& dest_size,
+                                   const SkIRect& dest_buffer_rect,
+                                   const SkIRect& dest_rect) {
+  // N.B. It is caller's responsibility to check if strides are large enough. We
+  // cannot do it here anyway.
+  DCHECK(SkIRect::MakeSize(source_size).contains(source_buffer_rect));
+  DCHECK(SkIRect::MakeSize(dest_size).contains(dest_buffer_rect));
+  DCHECK(dest_buffer_rect.contains(dest_rect));
+  DCHECK(ScaleRect(source_buffer_rect, source_size, dest_size).
+             contains(dest_rect));
+
+  // If the source and/or destination buffers don't start at (0, 0)
+  // offset the pointers to pretend we have complete buffers.
+  int y_offset = - CalculateYOffset(source_buffer_rect.x(),
+                                    source_buffer_rect.y(),
+                                    source_ystride);
+  int uv_offset = - CalculateUVOffset(source_buffer_rect.x(),
+                                      source_buffer_rect.y(),
+                                      source_uvstride);
+  int rgb_offset = - CalculateRGBOffset(dest_buffer_rect.x(),
+                                        dest_buffer_rect.y(),
+                                        dest_stride);
+
+  // See if scaling is needed.
+  if (source_size == dest_size) {
+    // Calculate the inner rectangle that can be copied by the optimized
+    // ConvertYUVToRGB32().
+    SkIRect inner_rect =
+        SkIRect::MakeLTRB(RoundToTwosMultiple(dest_rect.left() + 1),
+                          RoundToTwosMultiple(dest_rect.top() + 1),
+                          dest_rect.right(),
+                          dest_rect.bottom());
+
+    // Offset pointers to point to the top left corner of the inner rectangle.
+    y_offset += CalculateYOffset(inner_rect.x(), inner_rect.y(),
+                                 source_ystride);
+    uv_offset += CalculateUVOffset(inner_rect.x(), inner_rect.y(),
+                                   source_uvstride);
+    rgb_offset += CalculateRGBOffset(inner_rect.x(), inner_rect.y(),
+                                     dest_stride);
+
+    media::ConvertYUVToRGB32(source_yplane + y_offset,
+                             source_uplane + uv_offset,
+                             source_vplane + uv_offset,
+                             dest_buffer + rgb_offset,
+                             inner_rect.width(),
+                             inner_rect.height(),
+                             source_ystride,
+                             source_uvstride,
+                             dest_stride,
+                             media::YV12);
+
+    // Now see if some pixels weren't copied due to alignment.
+    if (dest_rect != inner_rect) {
+      SkIRect outer_rect =
+        SkIRect::MakeLTRB(RoundToTwosMultiple(dest_rect.left()),
+                          RoundToTwosMultiple(dest_rect.top()),
+                          dest_rect.right(),
+                          dest_rect.bottom());
+
+      SkIPoint offset = SkIPoint::Make(outer_rect.x() - inner_rect.x(),
+                                       outer_rect.y() - inner_rect.y());
+
+      // Offset the pointers to point to the top left corner of the outer
+      // rectangle.
+      y_offset += CalculateYOffset(offset.x(), offset.y(), source_ystride);
+      uv_offset += CalculateUVOffset(offset.x(), offset.y(), source_uvstride);
+      rgb_offset += CalculateRGBOffset(offset.x(), offset.y(), dest_stride);
+
+      // Draw unaligned edges.
+      SkRegion edges(dest_rect);
+      edges.op(inner_rect, SkRegion::kDifference_Op);
+      for (SkRegion::Iterator i(edges); !i.done(); i.next()) {
+        SkIRect rect(i.rect());
+        rect.offset(- outer_rect.left(), - outer_rect.top());
+        media::ScaleYUVToRGB32WithRect(source_yplane + y_offset,
+                                       source_uplane + uv_offset,
+                                       source_vplane + uv_offset,
+                                       dest_buffer + rgb_offset,
+                                       source_size.width(),
+                                       source_size.height(),
+                                       dest_size.width(),
+                                       dest_size.height(),
+                                       rect.left(),
+                                       rect.top(),
+                                       rect.right(),
+                                       rect.bottom(),
+                                       source_ystride,
+                                       source_uvstride,
+                                       dest_stride);
+      }
+    }
+  } else {
+    media::ScaleYUVToRGB32WithRect(source_yplane + y_offset,
+                                   source_uplane + uv_offset,
+                                   source_vplane + uv_offset,
+                                   dest_buffer + rgb_offset,
+                                   source_size.width(),
+                                   source_size.height(),
+                                   dest_size.width(),
+                                   dest_size.height(),
+                                   dest_rect.left(),
+                                   dest_rect.top(),
+                                   dest_rect.right(),
+                                   dest_rect.bottom(),
+                                   source_ystride,
+                                   source_uvstride,
+                                   dest_stride);
+  }
+}
+
 int RoundToTwosMultiple(int x) {
   return x & (~1);
 }
@@ -153,4 +251,31 @@ void CopyRect(const uint8* src_plane,
   }
 }
 
+void CopyRGB32Rect(const uint8* source_buffer,
+                   int source_stride,
+                   const SkIRect& source_buffer_rect,
+                   uint8* dest_buffer,
+                   int dest_stride,
+                   const SkIRect& dest_buffer_rect,
+                   const SkIRect& dest_rect) {
+  DCHECK(dest_buffer_rect.contains(dest_rect));
+  DCHECK(source_buffer_rect.contains(dest_rect));
+
+  // Get the address of the starting point.
+  int source_offset = CalculateRGBOffset(dest_rect.x() - source_buffer_rect.x(),
+                                         dest_rect.y() - source_buffer_rect.y(),
+                                         source_stride);
+  int dest_offset = CalculateRGBOffset(dest_rect.x() - dest_buffer_rect.x(),
+                                       dest_rect.y() - dest_buffer_rect.y(),
+                                       source_stride);
+
+  // Copy bits.
+  CopyRect(source_buffer + source_offset,
+           source_stride,
+           dest_buffer + dest_offset,
+           dest_stride,
+           GetBytesPerPixel(media::VideoFrame::RGB32),
+           SkIRect::MakeWH(dest_rect.width(), dest_rect.height()));
+}
+
 }  // namespace remoting