cc/layers/picture_layer.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/layers/picture_layer.h"

#include "cc/layers/content_layer_client.h"
#include "cc/layers/picture_layer_impl.h"
#include "cc/trees/layer_tree_impl.h"
#include "ui/gfx/rect_conversions.h"

namespace cc {

scoped_refptr<PictureLayer> PictureLayer::Create(ContentLayerClient* client) {
  return make_scoped_refptr(new PictureLayer(client));
}

PictureLayer::PictureLayer(ContentLayerClient* client)
    : client_(client),
      pile_(make_scoped_refptr(new PicturePile())),
      instrumentation_object_tracker_(id()),
      is_mask_(false),
      has_gpu_rasterization_hint_(TRIBOOL_UNKNOWN),
      update_source_frame_number_(-1) {}

PictureLayer::~PictureLayer() {
}

bool PictureLayer::DrawsContent() const {
  return Layer::DrawsContent() && client_;
}

scoped_ptr<LayerImpl> PictureLayer::CreateLayerImpl(LayerTreeImpl* tree_impl) {
  return PictureLayerImpl::Create(tree_impl, id()).PassAs<LayerImpl>();
}

void PictureLayer::PushPropertiesTo(LayerImpl* base_layer) {
  Layer::PushPropertiesTo(base_layer);
  PictureLayerImpl* layer_impl = static_cast<PictureLayerImpl*>(base_layer);

  if (layer_impl->bounds().IsEmpty()) {
    // Update may not get called for an empty layer, so resize here instead.
    // Using layer_impl because either bounds() or paint_properties().bounds
    // may disagree and either one could have been pushed to layer_impl.
    pile_->Resize(gfx::Size());
  } else if (update_source_frame_number_ ==
             layer_tree_host()->source_frame_number()) {
    // If update called, then pile size must match bounds pushed to impl layer.
    DCHECK_EQ(layer_impl->bounds().ToString(), pile_->size().ToString());
  }

  layer_impl->SetIsMask(is_mask_);
  layer_impl->SetUseGpuRasterization(ShouldUseGpuRasterization());

  // Unlike other properties, invalidation must always be set on layer_impl.
  // See PictureLayerImpl::PushPropertiesTo for more details.
  layer_impl->invalidation_.Clear();
  layer_impl->invalidation_.Swap(&pile_invalidation_);
  layer_impl->pile_ = PicturePileImpl::CreateFromOther(pile_.get());
}

void PictureLayer::SetLayerTreeHost(LayerTreeHost* host) {
  Layer::SetLayerTreeHost(host);
  if (host) {
    pile_->SetMinContentsScale(host->settings().minimum_contents_scale);
    pile_->SetTileGridSize(host->settings().default_tile_size);
    pile_->set_slow_down_raster_scale_factor(
        host->debug_state().slow_down_raster_scale_factor);
    pile_->set_show_debug_picture_borders(
        host->debug_state().show_picture_borders);
  }
}

void PictureLayer::SetNeedsDisplayRect(const gfx::RectF& layer_rect) {
  gfx::Rect rect = gfx::ToEnclosedRect(layer_rect);
  if (!rect.IsEmpty()) {
    // Clamp invalidation to the layer bounds.
    rect.Intersect(gfx::Rect(bounds()));
    pending_invalidation_.Union(rect);
  }
  Layer::SetNeedsDisplayRect(layer_rect);
}

bool PictureLayer::Update(ResourceUpdateQueue* queue,
                          const OcclusionTracker<Layer>* occlusion) {
  update_source_frame_number_ = layer_tree_host()->source_frame_number();
  bool updated = Layer::Update(queue, occlusion);

  if (last_updated_visible_content_rect_ == visible_content_rect() &&
      pile_->size() == paint_properties().bounds &&
      pending_invalidation_.IsEmpty()) {
    // Only early out if the visible content rect of this layer hasn't changed.
    return updated;
  }

  TRACE_EVENT1("cc", "PictureLayer::Update",
               "source_frame_number",
               layer_tree_host()->source_frame_number());

  pile_->Resize(paint_properties().bounds);

  // Calling paint in WebKit can sometimes cause invalidations, so save
  // off the invalidation prior to calling update.
  pending_invalidation_.Swap(&pile_invalidation_);
  pending_invalidation_.Clear();

  gfx::Rect visible_layer_rect = gfx::ScaleToEnclosingRect(
      visible_content_rect(), 1.f / contents_scale_x());
  if (layer_tree_host()->settings().using_synchronous_renderer_compositor) {
    // Workaround for http://crbug.com/235910 - to retain backwards compat
    // the full page content must always be provided in the picture layer.
    visible_layer_rect = gfx::Rect(bounds());
  }
  DCHECK(client_);
  updated |= pile_->Update(client_,
                           SafeOpaqueBackgroundColor(),
                           contents_opaque(),
                           client_->FillsBoundsCompletely(),
                           pile_invalidation_,
                           visible_layer_rect,
                           update_source_frame_number_,
                           rendering_stats_instrumentation());
  last_updated_visible_content_rect_ = visible_content_rect();

  if (updated) {
    SetNeedsPushProperties();
  } else {
    // If this invalidation did not affect the pile, then it can be cleared as
    // an optimization.
    pile_invalidation_.Clear();
  }

  return updated;
}

void PictureLayer::SetIsMask(bool is_mask) {
  is_mask_ = is_mask;
}

void PictureLayer::SetHasGpuRasterizationHint(bool has_hint) {
  switch (has_gpu_rasterization_hint_) {
    case TRIBOOL_UNKNOWN:  // Fall-through.
    case TRIBOOL_TRUE:
      has_gpu_rasterization_hint_ = has_hint ? TRIBOOL_TRUE : TRIBOOL_FALSE;
      break;
    case TRIBOOL_FALSE:
      // GPU rasterization cannot be enabled once disabled.
      // This is done to prevent frequent invalidations and visual flashing.
      break;
    default:
      NOTREACHED();
  }
  // No need to set needs commit or push-properties.
  // If only the hint changes and the layer is still valid, there is no need
  // to invalidate the rasterization for the whole layer. If there is an
  // invalidation (current or future) we will re-raster everything so that it
  // is consistent across the layer.
}

bool PictureLayer::ShouldUseGpuRasterization() const {
  switch (layer_tree_host()->settings().rasterization_site) {
    case LayerTreeSettings::CpuRasterization:
      return false;
    case LayerTreeSettings::HybridRasterization:
      return has_gpu_rasterization_hint_ == TRIBOOL_TRUE &&
             pile_->is_suitable_for_gpu_rasterization();
    case LayerTreeSettings::GpuRasterization:
      return true;
  }
  NOTREACHED();
  return false;
}

bool PictureLayer::SupportsLCDText() const {
  return true;
}

skia::RefPtr<SkPicture> PictureLayer::GetPicture() const {
  // We could either flatten the PicturePile into a single SkPicture,
  // or paint a fresh one depending on what we intend to do with the
  // picture. For now we just paint a fresh one to get consistent results.
  if (!DrawsContent())
    return skia::RefPtr<SkPicture>();

  int width = bounds().width();
  int height = bounds().height();
  gfx::RectF opaque;

  skia::RefPtr<SkPicture> picture = skia::AdoptRef(new SkPicture);
  SkCanvas* canvas = picture->beginRecording(width, height);
  client_->PaintContents(canvas, gfx::Rect(width, height), &opaque);
  picture->endRecording();
  return picture;
}

void PictureLayer::RunMicroBenchmark(MicroBenchmark* benchmark) {
  benchmark->RunOnLayer(this);
}

}  // namespace cc