Mozart: Implement hit testing.

services/gfx/compositor/graph/node_def.h

 // Copyright 2015 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.
 
 #ifndef SERVICES_GFX_COMPOSITOR_GRAPH_NODE_DEF_H_
 #define SERVICES_GFX_COMPOSITOR_GRAPH_NODE_DEF_H_
 
 #include <iosfwd>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "mojo/services/gfx/composition/interfaces/nodes.mojom.h"
 #include "services/gfx/compositor/graph/snapshot.h"
 
 class SkCanvas;
+struct SkPoint;
+class SkMatrix;
 
 namespace compositor {
 
 class SceneContent;
 class SceneContentBuilder;
 class SceneDef;
 
 // Represents a scene graph node.
 //
 // The base class mainly acts as a container for other nodes and does not
 // draw any content of its own.
 //
 // Instances of this class are immutable and reference counted so they may
 // be shared by multiple versions of the same scene.
 class NodeDef : public base::RefCounted<NodeDef> {
  public:
   using Combinator = mojo::gfx::composition::Node::Combinator;
 
   NodeDef(uint32_t node_id,
           mojo::TransformPtr content_transform,
           mojo::RectPtr content_clip,
+          mojo::gfx::composition::HitTestBehaviorPtr hit_test_behavior,
           Combinator combinator,
           const std::vector<uint32_t>& child_node_ids);
 
   uint32_t node_id() const { return node_id_; }
   const mojo::Transform* content_transform() const {
     return content_transform_.get();
   }
+  const mojo::gfx::composition::HitTestBehavior* hit_test_behavior() const {
+    return hit_test_behavior_.get();
+  }
   const mojo::Rect* content_clip() const { return content_clip_.get(); }
   Combinator combinator() const { return combinator_; }
   const std::vector<uint32_t>& child_node_ids() const {
     return child_node_ids_;
   }
 
   // Gets a descriptive label.
   std::string FormattedLabel(const SceneContent* content) const;
 
   // Called by the scene content builder to traverse the node's dependencies
   // recursively and ensure they are included in the scene's local content.
   // Returns true if successful, false if the node contains linkage errors.
   virtual bool RecordContent(SceneContentBuilder* builder) const;
 
   // Called by the snapshot builder to traverse the node's dependencies
   // recursively follow links into other scenes, evaluate whether the
   // node can be rendered, and record which path was taken for the purposes
   // of satisfying combinators.
   virtual Snapshot::Disposition RecordSnapshot(const SceneContent* content,
                                                SnapshotBuilder* builder) const;
 
   // Called to record drawing commands from a snapshot.
   void RecordPicture(const SceneContent* content,
                      const Snapshot* snapshot,
                      SkCanvas* canvas) const;
 
+  // Performs a hit test at the specified point.
+  // The |global_point| is the original hit tested point.
+  // The |parent_transform| is the accumulated transform from the parent's
+  // coordinate space to the global coordinate space.
+  // Adds hit information for the node to the array.
+  void HitTest(const SceneContent* content,
+               const Snapshot* snapshot,
+               const SkPoint& global_point,
+               const SkMatrix& parent_transform,

[abarth, 2016/03/09 04:02:48]

Don't you want an SkMatrix44 here?

[jeffbrown, 2016/03/09 20:32:11]

I didn't know that existed!  ha!  I'll make a note for later.

+               bool* opaque,
+               mojo::Array<mojo::gfx::composition::HitPtr>* hits) const;
+
  protected:
   friend class base::RefCounted<NodeDef>;
   virtual ~NodeDef();
 
   // Applies a unary function to the children selected by the node's
   // combinator rule during a snapshot.
   // Stops when |Func| returns false.
   // |Func| should have the signature |bool func(const NodeDef*)|.
   template <typename Func>
   void TraverseSnapshottedChildren(const SceneContent* content,
                                    const Snapshot* snapshot,
                                    const Func& func) const;
 
   virtual void RecordPictureInner(const SceneContent* content,
                                   const Snapshot* snapshot,
                                   SkCanvas* canvas) const;
 
+  virtual void HitTestInner(
+      const SceneContent* content,
+      const Snapshot* snapshot,
+      const SkPoint& global_point,
+      const SkMatrix& node_transform,
+      bool* opaque,
+      mojo::Array<mojo::gfx::composition::HitPtr>* hits) const;
+
  private:
   uint32_t const node_id_;
   mojo::TransformPtr const content_transform_;
   mojo::RectPtr const content_clip_;
+  mojo::gfx::composition::HitTestBehaviorPtr const hit_test_behavior_;
   Combinator const combinator_;
   std::vector<uint32_t> const child_node_ids_;
 
   DISALLOW_COPY_AND_ASSIGN(NodeDef);
 };
 
 // Represents a rectangle node.
 //
 // Draws a solid color filled rectangle node underneath its children.
 class RectNodeDef : public NodeDef {
  public:
   RectNodeDef(uint32_t node_id,
               mojo::TransformPtr content_transform,
               mojo::RectPtr content_clip,
+              mojo::gfx::composition::HitTestBehaviorPtr hit_test_behavior,
               Combinator combinator,
               const std::vector<uint32_t>& child_node_ids,
               const mojo::Rect& content_rect,
               const mojo::gfx::composition::Color& color);
 
   const mojo::Rect& content_rect() const { return content_rect_; }
   const mojo::gfx::composition::Color& color() const { return color_; }
 
  protected:
   ~RectNodeDef() override;
@@ skipping 10 matching lines @@
 };
 
 // Represents an image node.
 //
 // Draws an image filled rectangle underneath its children.
 class ImageNodeDef : public NodeDef {
  public:
   ImageNodeDef(uint32_t node_id,
                mojo::TransformPtr content_transform,
                mojo::RectPtr content_clip,
+               mojo::gfx::composition::HitTestBehaviorPtr hit_test_behavior,
                Combinator combinator,
                const std::vector<uint32_t>& child_node_ids,
                const mojo::Rect& content_rect,
                mojo::RectPtr image_rect,
                uint32 image_resource_id,
                mojo::gfx::composition::BlendPtr blend);
 
   const mojo::Rect& content_rect() const { return content_rect_; }
   const mojo::Rect* image_rect() const { return image_rect_.get(); }
   uint32_t image_resource_id() const { return image_resource_id_; }
@@ skipping 18 matching lines @@
 };
 
 // Represents a scene node.
 //
 // Draws an embedded scene underneath its children.
 class SceneNodeDef : public NodeDef {
  public:
   SceneNodeDef(uint32_t node_id,
                mojo::TransformPtr content_transform,
                mojo::RectPtr content_clip,
+               mojo::gfx::composition::HitTestBehaviorPtr hit_test_behavior,
                Combinator combinator,
                const std::vector<uint32_t>& child_node_ids,
                uint32_t scene_resource_id,
                uint32_t scene_version);
 
   uint32_t scene_resource_id() const { return scene_resource_id_; }
   uint32_t scene_version() const { return scene_version_; }
 
   bool RecordContent(SceneContentBuilder* builder) const override;
 
   Snapshot::Disposition RecordSnapshot(const SceneContent* content,
                                        SnapshotBuilder* builder) const override;
 
  protected:
   ~SceneNodeDef() override;
 
   void RecordPictureInner(const SceneContent* content,
                           const Snapshot* snapshot,
                           SkCanvas* canvas) const override;
 
+  void HitTestInner(
+      const SceneContent* content,
+      const Snapshot* snapshot,
+      const SkPoint& global_point,
+      const SkMatrix& node_transform,
+      bool* opaque,
+      mojo::Array<mojo::gfx::composition::HitPtr>* hits) const override;
+
  private:
   uint32_t const scene_resource_id_;
   uint32_t const scene_version_;
 
   DISALLOW_COPY_AND_ASSIGN(SceneNodeDef);
 };
 
 // Represents a layer node.
 //
 // Composites its children to a layer and applies a blending operation.
 class LayerNodeDef : public NodeDef {
  public:
   LayerNodeDef(uint32_t node_id,
                mojo::TransformPtr content_transform,
                mojo::RectPtr content_clip,
+               mojo::gfx::composition::HitTestBehaviorPtr hit_test_behavior,
                Combinator combinator,
                const std::vector<uint32_t>& child_node_ids,
                const mojo::Size& size,
                mojo::gfx::composition::BlendPtr blend);
 
   const mojo::Size& size() const { return size_; }
   const mojo::gfx::composition::Blend* blend() const { return blend_.get(); }
 
  protected:
   ~LayerNodeDef() override;
 
   void RecordPictureInner(const SceneContent* content,
                           const Snapshot* snapshot,
                           SkCanvas* canvas) const override;
 
  private:
   mojo::Size const size_;
   mojo::gfx::composition::BlendPtr const blend_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerNodeDef);
 };
 
 }  // namespace compositor
 
 #endif  // SERVICES_GFX_COMPOSITOR_GRAPH_NODE_DEF_H_