Add test for RotatePlaneByPixels.

This is a follow-up patch for https://codereview.chromium.org/11860002/

BUG=161417
Review URL: https://codereview.chromium.org/12207190

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@183257 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 101 insertions, 0 deletions

diff --git a/media/base/video_util.cc b/media/base/video_util.cc
index 487c595..d7498ad 100644
--- a/media/base/video_util.cc
+++ b/media/base/video_util.cc
@@ -85,4 +85,105 @@ void FillYUV(VideoFrame* frame, uint8 y, uint8 u, uint8 v) {
   }
 }
 
+void RotatePlaneByPixels(
+    uint8* src,
+    uint8* dest,
+    int width,
+    int height,
+    int rotation,  // Clockwise.
+    bool flip_vert,
+    bool flip_horiz) {
+  DCHECK((width > 0) && (height > 0) &&
+         ((width & 1) == 0) && ((height & 1) == 0) &&
+         (rotation >= 0) && (rotation < 360) && (rotation % 90 == 0));
+
+  // Consolidate cases. Only 0 and 90 are left.
+  if (rotation == 180 || rotation == 270) {
+    rotation -= 180;
+    flip_vert = !flip_vert;
+    flip_horiz = !flip_horiz;
+  }
+
+  int num_rows = height;
+  int num_cols = width;
+  int src_stride = width;
+  // During pixel copying, the corresponding incremental of dest pointer
+  // when src pointer moves to next row.
+  int dest_row_step = width;
+  // During pixel copying, the corresponding incremental of dest pointer
+  // when src pointer moves to next column.
+  int dest_col_step = 1;
+
+  if (rotation == 0) {
+    if (flip_horiz) {
+      // Use pixel copying.
+      dest_col_step = -1;
+      if (flip_vert) {
+        // Rotation 180.
+        dest_row_step = -width;
+        dest += height * width - 1;
+      } else {
+        dest += width - 1;
+      }
+    } else {
+      if (flip_vert) {
+        // Fast copy by rows.
+        dest += width * (height - 1);
+        for (int row = 0; row < height; ++row) {
+          memcpy(dest, src, width);
+          src += width;
+          dest -= width;
+        }
+      } else {
+        memcpy(dest, src, width * height);
+      }
+      return;
+    }
+  } else if (rotation == 90) {
+    int offset;
+    if (width > height) {
+      offset = (width - height) / 2;
+      src += offset;
+      num_rows = num_cols = height;
+    } else {
+      offset = (height - width) / 2;
+      src += width * offset;
+      num_rows = num_cols = width;
+    }
+
+    dest_col_step = (flip_vert ? -width : width);
+    dest_row_step = (flip_horiz ? 1 : -1);
+    if (flip_horiz) {
+      if (flip_vert) {
+        dest += (width > height ? width * (height - 1) + offset :
+                                  width * (height - offset - 1));
+      } else {
+        dest += (width > height ? offset : width * offset);
+      }
+    } else {
+      if (flip_vert) {
+        dest += (width > height ?  width * height - offset - 1 :
+                                   width * (height - offset) - 1);
+      } else {
+        dest += (width > height ? width - offset - 1 :
+                                  width * (offset + 1) - 1);
+      }
+    }
+  } else {
+    NOTREACHED();
+  }
+
+  // Copy pixels.
+  for (int row = 0; row < num_rows; ++row) {
+    uint8* src_ptr = src;
+    uint8* dest_ptr = dest;
+    for (int col = 0; col < num_cols; ++col) {
+      *dest_ptr = *src_ptr++;
+      dest_ptr += dest_col_step;
+    }
+    src += src_stride;
+    dest += dest_row_step;
+  }
+}
+
 }  // namespace media