Refactor scaling.

webrtc/common_video/video_frame_buffer.cc

Index: webrtc/common_video/video_frame_buffer.cc
diff --git a/webrtc/common_video/video_frame_buffer.cc b/webrtc/common_video/video_frame_buffer.cc
index 34213e4656ce766f5cb6f2fdc24e566c02cf152e..2013596fcbf2dfcc933431c982118c730b0608c5 100644
--- a/webrtc/common_video/video_frame_buffer.cc
+++ b/webrtc/common_video/video_frame_buffer.cc
@@ -8,11 +8,14 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#include <algorithm>
+
 #include "webrtc/common_video/include/video_frame_buffer.h"
 
 #include "webrtc/base/checks.h"
 #include "webrtc/base/keep_ref_until_done.h"
 #include "libyuv/convert.h"
+#include "libyuv/scale.h"
 
 // Aligning pointer to 64 bytes for improved performance, e.g. use SIMD.
 static const int kBufferAlignment = 64;
@@ -200,6 +203,57 @@ rtc::scoped_refptr<I420Buffer> I420Buffer::Copy(
   return copy;
 }
 
+void I420Buffer::CropAndScale(
+    const rtc::scoped_refptr<VideoFrameBuffer>& buffer,
+    int offset_x,
+    int offset_y,
+    int crop_width,
+    int crop_height) {
+  RTC_CHECK_LE(crop_width, buffer->width());
+  RTC_CHECK_LE(crop_height, buffer->height());
+  RTC_CHECK_LE(crop_width + offset_x, buffer->width());
+  RTC_CHECK_LE(crop_height + offset_y, buffer->height());
+  RTC_CHECK_GE(offset_x, 0);
+  RTC_CHECK_GE(offset_y, 0);
+
+  // Make sure offset is even so that u/v plane becomes aligned.
+  const int uv_offset_x = offset_x / 2;
+  const int uv_offset_y = offset_y / 2;
+  offset_x = uv_offset_x * 2;
+  offset_y = uv_offset_y * 2;
+
+  const uint8_t* y_plane =
+      buffer->DataY() + buffer->StrideY() * offset_y + offset_x;
+  const uint8_t* u_plane =
+      buffer->DataU() + buffer->StrideU() * uv_offset_y + uv_offset_x;
+  const uint8_t* v_plane =
+      buffer->DataV() + buffer->StrideV() * uv_offset_y + uv_offset_x;
+  int res = libyuv::I420Scale(y_plane, buffer->StrideY(),
+                              u_plane, buffer->StrideU(),
+                              v_plane, buffer->StrideV(),
+                              crop_width, crop_height,
+                              MutableDataY(), StrideY(),
+                              MutableDataU(), StrideU(),
+                              MutableDataV(), StrideV(),
+                              width(), height(), libyuv::kFilterBox);
+
+  RTC_DCHECK(res == 0);

[magjed_webrtc, 2016/05/30 11:58:26]

Use RTC_DCHECK_EQ instead

[nisse-webrtc, 2016/05/30 12:58:22]

Done.

+}
+
+void I420Buffer::CenterCropAndScale(
+    const rtc::scoped_refptr<I420Buffer>& dst,
+    const rtc::scoped_refptr<VideoFrameBuffer>& src) {
+  const int crop_width =
+      std::min(src->width(), dst->width() * src->height() / dst->height());
+  const int crop_height =
+      std::min(src->height(), dst->height() * src->width() / dst->width());
+
+  dst->CropAndScale(
+      src,
+      (src->width() - crop_width) / 2, (src->height() - crop_height) / 2,
+      crop_width, crop_height);
+}
+
 NativeHandleBuffer::NativeHandleBuffer(void* native_handle,
                                        int width,
                                        int height)