Allow images rasterized by the picture rasterizer to be highlighted for debugging purposes

sky/compositor/BUILD.gn

@@ -12,6 +12,9 @@ source_set("compositor") {
     "clip_rrect_layer.h",
     "color_filter_layer.cc",
     "color_filter_layer.h",
+    "compositor_config.h",
+    "compositor_tools.cc",
+    "compositor_tools.h",
     "container_layer.cc",
     "container_layer.h",
     "layer.cc",

sky/compositor/compositor_config.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SKY_COMPOSITOR_COMPOSITOR_CONFIG_H_
+#define SKY_COMPOSITOR_COMPOSITOR_CONFIG_H_
+
+// SkPictures that dont mutate from frame to frame are rasterized by the picture
+// rasterizer. This guard enables highlighting the rasterized images. Useful
+// when debugging caching
+#define COMPOSITOR_HIGHLIGHT_RASTERIZED_PICTURES 0
+
+#endif  // SKY_COMPOSITOR_COMPOSITOR_CONFIG_H_

sky/compositor/compositor_tools.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "sky/compositor/compositor_tools.h"
+#include "third_party/skia/include/core/SkShader.h"
+
+namespace sky {
+namespace compositor {
+
+static SkShader* CreateCheckerboardShader(SkColor c1, SkColor c2, int size) {
+  SkBitmap bm;
+  bm.allocN32Pixels(2 * size, 2 * size);
+  bm.eraseColor(c1);
+  bm.eraseArea(SkIRect::MakeLTRB(0, 0, size, size), c2);
+  bm.eraseArea(SkIRect::MakeLTRB(size, size, 2 * size, 2 * size), c2);
+  return SkShader::CreateBitmapShader(bm, SkShader::kRepeat_TileMode,
+                                      SkShader::kRepeat_TileMode);
+}
+
+static void DrawCheckerboard(SkCanvas* canvas,
+                             SkColor c1,
+                             SkColor c2,
+                             int size) {
+  SkPaint paint;
+  paint.setShader(CreateCheckerboardShader(c1, c2, size))->unref();
+  canvas->drawPaint(paint);
+}
+
+void DrawCheckerboard(SkCanvas* canvas, int width, int height) {
+  SkRect rect = SkRect::MakeIWH(width, height);
+
+  // Draw a checkerboard
+  canvas->clipRect(rect);
+  DrawCheckerboard(canvas, 0x9900FF00, 0x00000000, 12);
+
+  // Stroke the drawn area
+  SkPaint debugPaint;
+  debugPaint.setStrokeWidth(3);
+  debugPaint.setColor(SK_ColorRED);
+  debugPaint.setStyle(SkPaint::kStroke_Style);
+  canvas->drawRect(rect, debugPaint);
+}
+
+}  // namespace compositor
+}  // namespace sky

sky/compositor/compositor_tools.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SKY_COMPOSITOR_COMPOSITOR_TOOLS_H_
+#define SKY_COMPOSITOR_COMPOSITOR_TOOLS_H_
+
+#include "third_party/skia/include/core/SkCanvas.h"
+
+namespace sky {
+namespace compositor {
+
+void DrawCheckerboard(SkCanvas* canvas, int width, int height);
+
+}  // namespace compositor
+}  // namespace sky
+
+#endif  // SKY_COMPOSITOR_COMPOSITOR_TOOLS_H_

sky/compositor/picture_rasterizer.cc

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "sky/compositor/compositor_config.h"
+#include "sky/compositor/compositor_tools.h"
 #include "sky/compositor/picture_rasterizer.h"
 #include "base/logging.h"
 #include "third_party/skia/include/core/SkPicture.h"
@@ -80,6 +82,10 @@ static RefPtr<SkImage> ImageFromPicture(GrContext* context,
 
   canvas->drawPicture(picture);
 
+#if COMPOSITOR_HIGHLIGHT_RASTERIZED_PICTURES
+  DrawCheckerboard(canvas, desc.fWidth, desc.fHeight);
+#endif
+
   // Step 4: Create an image representation from the texture
 
   RefPtr<SkImage> image = adoptRef(SkImage::NewFromTexture(