// Copyright 2010 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/layers/picture_image_layer.h"

#include <stddef.h>

#include "cc/layers/picture_image_layer_impl.h"
#include "cc/playback/display_item_list_settings.h"
#include "cc/playback/drawing_display_item.h"
#include "third_party/skia/include/core/SkCanvas.h"
#include "third_party/skia/include/core/SkImage.h"
#include "third_party/skia/include/core/SkPictureRecorder.h"
#include "ui/gfx/skia_util.h"

namespace cc {

scoped_refptr<PictureImageLayer> PictureImageLayer::Create() {
  return make_scoped_refptr(new PictureImageLayer());
}

PictureImageLayer::PictureImageLayer() : PictureLayer(this) {}

PictureImageLayer::~PictureImageLayer() {
  ClearClient();
}

scoped_ptr<LayerImpl> PictureImageLayer::CreateLayerImpl(
    LayerTreeImpl* tree_impl) {
  return PictureImageLayerImpl::Create(tree_impl, id(), is_mask());
}

bool PictureImageLayer::HasDrawableContent() const {
  return image_ && PictureLayer::HasDrawableContent();
}

void PictureImageLayer::SetImage(skia::RefPtr<const SkImage> image) {
  // SetImage() currently gets called whenever there is any
  // style change that affects the layer even if that change doesn't
  // affect the actual contents of the image (e.g. a CSS animation).
  // With this check in place we avoid unecessary texture uploads.
  if (image_.get() == image.get())
    return;

  image_ = std::move(image);
  UpdateDrawsContent(HasDrawableContent());
  SetNeedsDisplay();
}

gfx::Rect PictureImageLayer::PaintableRegion() {
  return gfx::Rect(bounds());
}

scoped_refptr<DisplayItemList> PictureImageLayer::PaintContentsToDisplayList(
    ContentLayerClient::PaintingControlSetting painting_control) {
  DCHECK(image_);
  DCHECK_GT(image_->width(), 0);
  DCHECK_GT(image_->height(), 0);

  // Picture image layers can be used with GatherPixelRefs, so cached SkPictures
  // are currently required.
  DisplayItemListSettings settings;
  settings.use_cached_picture = true;
  scoped_refptr<DisplayItemList> display_list =
      DisplayItemList::Create(PaintableRegion(), settings);

  SkPictureRecorder recorder;
  SkCanvas* canvas =
      recorder.beginRecording(gfx::RectToSkRect(PaintableRegion()));

  SkScalar content_to_layer_scale_x =
      SkFloatToScalar(static_cast<float>(bounds().width()) / image_->width());
  SkScalar content_to_layer_scale_y =
      SkFloatToScalar(static_cast<float>(bounds().height()) / image_->height());
  canvas->scale(content_to_layer_scale_x, content_to_layer_scale_y);

  // Because Android WebView resourceless software draw mode rasters directly
  // to the root canvas, this draw must use the kSrcOver_Mode so that
  // transparent images blend correctly.
  canvas->drawImage(image_.get(), 0, 0);

  display_list->CreateAndAppendItem<DrawingDisplayItem>(
      PaintableRegion(), recorder.finishRecordingAsPicture());

  display_list->Finalize();
  return display_list;
}

bool PictureImageLayer::FillsBoundsCompletely() const {
  return false;
}

size_t PictureImageLayer::GetApproximateUnsharedMemoryUsage() const {
  return 0;
}

}  // namespace cc