Optimize alpha software PictureDrawQuads.

skia/ext/opacity_draw_filter.cc

+// Copyright (c) 2013 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 "skia/ext/opacity_draw_filter.h"
+#include "third_party/skia/include/core/SkPaint.h"
+
+namespace skia {
+
+OpacityDrawFilter::OpacityDrawFilter(float opacity,
+                                     bool disable_image_filtering)
+    : alpha_(SkScalarRound(opacity * 255)),
+      disable_image_filtering_(disable_image_filtering) {}
+
+OpacityDrawFilter::~OpacityDrawFilter() {}
+
+bool OpacityDrawFilter::filter(SkPaint* paint, Type type) {
+  if (alpha_ < 255)
+    paint->setAlpha(alpha_);
+  if (disable_image_filtering_)
+    paint->setFilterLevel(SkPaint::kNone_FilterLevel);
+  return true;
+}
+
+}  // namespace skia
+
+