flow/layers/container_layer.h

// 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.

#ifndef FLUTTER_FLOW_LAYERS_CONTAINER_LAYER_H_
#define FLUTTER_FLOW_LAYERS_CONTAINER_LAYER_H_

#include <vector>
#include "flutter/flow/layers/layer.h"

namespace flutter {

class ContainerLayer : public Layer {
 public:
  ContainerLayer();

  virtual void Add(std::shared_ptr<Layer> layer);

  void Preroll(PrerollContext* context, const SkMatrix& matrix) override;
  void Paint(PaintContext& context) const override;
#if defined(OS_FUCHSIA)
  void CheckForChildLayerBelow(PrerollContext* context) override;
  void UpdateScene(SceneUpdateContext& context) override;
#endif  // defined(OS_FUCHSIA)

  const std::vector<std::shared_ptr<Layer>>& layers() const { return layers_; }

 protected:
  void PrerollChildren(PrerollContext* context,
                       const SkMatrix& child_matrix,
                       SkRect* child_paint_bounds);
  void PaintChildren(PaintContext& context) const;

#if defined(OS_FUCHSIA)
  void UpdateSceneChildren(SceneUpdateContext& context);
#endif  // defined(OS_FUCHSIA)

  // For OpacityLayer to restructure to have a single child.
  void ClearChildren() { layers_.clear(); }

  // Try to prepare the raster cache for a given layer.
  //
  // The raster cache would fail if either of the followings is true:
  // 1. The context has a platform view.
  // 2. The context does not have a valid raster cache.
  // 3. The layer's paint bounds does not intersect with the cull rect.
  //
  // We make this a static function instead of a member function that directy
  // uses the "this" pointer as the layer because we sometimes need to raster
  // cache a child layer and one can't access its child's protected method.
  static void TryToPrepareRasterCache(PrerollContext* context,
                                      Layer* layer,
                                      const SkMatrix& matrix);

 private:
  std::vector<std::shared_ptr<Layer>> layers_;

  FML_DISALLOW_COPY_AND_ASSIGN(ContainerLayer);
};

}  // namespace flutter

#endif  // FLUTTER_FLOW_LAYERS_CONTAINER_LAYER_H_