cc/test/layer_tree_json_parser.cc

// Copyright 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 "cc/test/layer_tree_json_parser.h"

#include <stddef.h>

#include "base/test/values_test_util.h"
#include "base/values.h"
#include "cc/layers/layer.h"
#include "cc/layers/nine_patch_layer.h"
#include "cc/layers/picture_layer.h"
#include "cc/layers/solid_color_layer.h"
#include "cc/layers/texture_layer.h"
#include "cc/trees/layer_tree_settings.h"

namespace cc {

namespace {

scoped_refptr<Layer> ParseTreeFromValue(const base::Value& val,
                                        ContentLayerClient* content_client) {
  const base::DictionaryValue* dict;
  bool success = true;
  success &= val.GetAsDictionary(&dict);
  std::string layer_type;
  success &= dict->GetString("LayerType", &layer_type);
  const base::ListValue* list;
  success &= dict->GetList("Bounds", &list);
  int width, height;
  success &= list->GetInteger(0, &width);
  success &= list->GetInteger(1, &height);
  success &= dict->GetList("Position", &list);
  double position_x, position_y;
  success &= list->GetDouble(0, &position_x);
  success &= list->GetDouble(1, &position_y);

  bool draws_content;
  success &= dict->GetBoolean("DrawsContent", &draws_content);

  scoped_refptr<Layer> new_layer;
  if (layer_type == "SolidColorLayer") {
    new_layer = SolidColorLayer::Create();
  } else if (layer_type == "NinePatchLayer") {
    success &= dict->GetList("ImageAperture", &list);
    int aperture_x, aperture_y, aperture_width, aperture_height;
    success &= list->GetInteger(0, &aperture_x);
    success &= list->GetInteger(1, &aperture_y);
    success &= list->GetInteger(2, &aperture_width);
    success &= list->GetInteger(3, &aperture_height);

    const base::ListValue* bounds;
    success &= dict->GetList("ImageBounds", &bounds);
    double image_width, image_height;
    success &= bounds->GetDouble(0, &image_width);
    success &= bounds->GetDouble(1, &image_height);

    success &= dict->GetList("Border", &list);
    int border_x, border_y, border_width, border_height;
    success &= list->GetInteger(0, &border_x);
    success &= list->GetInteger(1, &border_y);
    success &= list->GetInteger(2, &border_width);
    success &= list->GetInteger(3, &border_height);

    bool fill_center;
    success &= dict->GetBoolean("FillCenter", &fill_center);

    scoped_refptr<NinePatchLayer> nine_patch_layer = NinePatchLayer::Create();

    SkBitmap bitmap;
    bitmap.allocN32Pixels(image_width, image_height);
    bitmap.setImmutable();
    nine_patch_layer->SetBitmap(bitmap);
    nine_patch_layer->SetAperture(
        gfx::Rect(aperture_x, aperture_y, aperture_width, aperture_height));
    nine_patch_layer->SetBorder(
        gfx::Rect(border_x, border_y, border_width, border_height));
    nine_patch_layer->SetFillCenter(fill_center);

    new_layer = nine_patch_layer;
  } else if (layer_type == "TextureLayer") {
    new_layer = TextureLayer::CreateForMailbox(NULL);
  } else if (layer_type == "PictureLayer") {
    new_layer = PictureLayer::Create(content_client);
  } else {  // Type "Layer" or "unknown"
    new_layer = Layer::Create();
  }
  new_layer->SetPosition(gfx::PointF(position_x, position_y));
  new_layer->SetBounds(gfx::Size(width, height));
  new_layer->SetIsDrawable(draws_content);

  double opacity;
  if (dict->GetDouble("Opacity", &opacity))
    new_layer->SetOpacity(opacity);

  bool contents_opaque;
  if (dict->GetBoolean("ContentsOpaque", &contents_opaque))
    new_layer->SetContentsOpaque(contents_opaque);

  bool scrollable;
  // TODO(wjmaclean) At some time in the future we may wish to test that a
  // reconstructed layer tree contains the correct linkage for the scroll
  // clip layer. This is complicated by the fact that the json output doesn't
  // (currently) re-construct the tree with the same layer IDs as the original.
  // But, since a clip layer is always an ancestor of the scrollable layer, we
  // can just count the number of upwards hops to the clip layer and write that
  // into the json file (with 0 hops implying no clip layer, i.e. not
  // scrollable). Reconstructing the tree can then be accomplished by passing
  // the parent pointer to this function and traversing the same number of
  // ancestors to determine the pointer to the clip layer. The LayerTreesMatch()
  // function should then check that both original and reconstructed layers
  // have the same positioning with respect to their clip layers.
  //
  // For now, we can safely indicate a layer is scrollable by giving it a
  // pointer to itself, something not normally allowed in a working tree.
  //
  // https://code.google.com/p/chromium/issues/detail?id=330622
  //
  if (dict->GetBoolean("Scrollable", &scrollable))
    new_layer->SetScrollClipLayerId(scrollable ? new_layer->id()
                                               : Layer::INVALID_ID);

  bool is_3d_sorted;
  if (dict->GetBoolean("Is3DSorted", &is_3d_sorted)) {
    // A non-zero context ID will put the layer into a 3D sorting context
    new_layer->Set3dSortingContextId(is_3d_sorted ? 1 : 0);
  }

  if (dict->HasKey("TouchRegion")) {
    success &= dict->GetList("TouchRegion", &list);
    Region touch_region;
    for (size_t i = 0; i < list->GetSize(); ) {
      int rect_x, rect_y, rect_width, rect_height;
      success &= list->GetInteger(i++, &rect_x);
      success &= list->GetInteger(i++, &rect_y);
      success &= list->GetInteger(i++, &rect_width);
      success &= list->GetInteger(i++, &rect_height);
      touch_region.Union(gfx::Rect(rect_x, rect_y, rect_width, rect_height));
    }
    new_layer->SetTouchEventHandlerRegion(touch_region);
  }

  success &= dict->GetList("Transform", &list);
  double transform[16];
  for (int i = 0; i < 16; ++i)
    success &= list->GetDouble(i, &transform[i]);

  gfx::Transform layer_transform;
  layer_transform.matrix().setColMajord(transform);
  new_layer->SetTransform(layer_transform);

  success &= dict->GetList("Children", &list);
  for (const auto& value : *list) {
    new_layer->AddChild(ParseTreeFromValue(*value, content_client));
  }

  if (!success)
    return NULL;

  return new_layer;
}

}  // namespace

scoped_refptr<Layer> ParseTreeFromJson(std::string json,
                                       ContentLayerClient* content_client) {
  std::unique_ptr<base::Value> val = base::test::ParseJson(json);
  return ParseTreeFromValue(*val, content_client);
}

}  // namespace cc