flow/layers/color_filter_layer.cc

// Copyright 2013 The Flutter 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 "flutter/flow/layers/color_filter_layer.h"

namespace flutter {

ColorFilterLayer::ColorFilterLayer(sk_sp<SkColorFilter> filter)
    : filter_(std::move(filter)), render_count_(1) {}

void ColorFilterLayer::Diff(DiffContext* context, const Layer* old_layer) {
  DiffContext::AutoSubtreeRestore subtree(context);
  auto* prev = static_cast<const ColorFilterLayer*>(old_layer);
  if (!context->IsSubtreeDirty()) {
    FML_DCHECK(prev);
    if (filter_ != prev->filter_) {
      context->MarkSubtreeDirty(context->GetOldLayerPaintRegion(old_layer));
    }
  }

  DiffChildren(context, prev);

  context->SetLayerPaintRegion(this, context->CurrentSubtreeRegion());
}

void ColorFilterLayer::Preroll(PrerollContext* context,
                               const SkMatrix& matrix) {
  Layer::AutoPrerollSaveLayerState save =
      Layer::AutoPrerollSaveLayerState::Create(context);
  ContainerLayer::Preroll(context, matrix);

  // We always use a saveLayer (or a cached rendering), so we
  // can always apply opacity in those cases.
  context->subtree_can_inherit_opacity = true;

  if (render_count_ >= kMinimumRendersBeforeCachingFilterLayer) {
    TryToPrepareRasterCache(context, this, matrix,
                            RasterCacheLayerStrategy::kLayer);
  } else {
    render_count_++;
    TryToPrepareRasterCache(context, this, matrix,
                            RasterCacheLayerStrategy::kLayerChildren);
  }
}

void ColorFilterLayer::Paint(PaintContext& context) const {
  TRACE_EVENT0("flutter", "ColorFilterLayer::Paint");
  FML_DCHECK(needs_painting(context));

  AutoCachePaint cache_paint(context);

  if (context.raster_cache) {
    if (context.raster_cache->Draw(this, *context.leaf_nodes_canvas,
                                   RasterCacheLayerStrategy::kLayer,
                                   cache_paint.paint())) {
      return;
    }

    cache_paint.setColorFilter(filter_);
    if (context.raster_cache->Draw(this, *context.leaf_nodes_canvas,
                                   RasterCacheLayerStrategy::kLayerChildren,
                                   cache_paint.paint())) {
      return;
    }
  }

  cache_paint.setColorFilter(filter_);

  Layer::AutoSaveLayer save = Layer::AutoSaveLayer::Create(
      context, paint_bounds(), cache_paint.paint());
  PaintChildren(context);
}

}  // namespace flutter