cc/resources/caching_bitmap_content_layer_updater.cc

// Copyright 2012 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 "cc/resources/caching_bitmap_content_layer_updater.h"

#include "base/logging.h"
#include "cc/resources/layer_painter.h"
#include "skia/ext/platform_canvas.h"

namespace cc {

scoped_refptr<CachingBitmapContentLayerUpdater>
CachingBitmapContentLayerUpdater::Create(
    scoped_ptr<LayerPainter> painter,
    RenderingStatsInstrumentation* stats_instrumentation,
    int layer_id) {
  return make_scoped_refptr(
      new CachingBitmapContentLayerUpdater(painter.Pass(),
                                           stats_instrumentation,
                                           layer_id));
}

CachingBitmapContentLayerUpdater::CachingBitmapContentLayerUpdater(
    scoped_ptr<LayerPainter> painter,
    RenderingStatsInstrumentation* stats_instrumentation,
    int layer_id)
    : BitmapContentLayerUpdater(painter.Pass(),
                                stats_instrumentation,
                                layer_id),
      pixels_did_change_(false) {}

CachingBitmapContentLayerUpdater::~CachingBitmapContentLayerUpdater() {}

void CachingBitmapContentLayerUpdater::PrepareToUpdate(
    gfx::Rect content_rect,
    gfx::Size tile_size,
    float contents_width_scale,
    float contents_height_scale,
    gfx::Rect* resulting_opaque_rect) {
  BitmapContentLayerUpdater::PrepareToUpdate(content_rect,
                                             tile_size,
                                             contents_width_scale,
                                             contents_height_scale,
                                             resulting_opaque_rect);

  const SkBitmap& new_bitmap = canvas_->getDevice()->accessBitmap(false);
  SkAutoLockPixels lock(new_bitmap);
  DCHECK_GT(new_bitmap.bytesPerPixel(), 0);
  pixels_did_change_ = new_bitmap.config() != cached_bitmap_.config() ||
                       new_bitmap.height() != cached_bitmap_.height() ||
                       new_bitmap.width() != cached_bitmap_.width() ||
                       memcmp(new_bitmap.getPixels(),
                              cached_bitmap_.getPixels(),
                              new_bitmap.getSafeSize());

  if (pixels_did_change_)
    new_bitmap.deepCopyTo(&cached_bitmap_, new_bitmap.config());
}

}  // namespace cc