Decouple Canvas from DisplayList and map Picture and PictureRecorder more directly to their Skia co…

sky/examples/game/lib/node_with_size.dart

 part of sprites;
 
 /// The super class of any [Node] that has a size.
 ///
 /// NodeWithSize adds the ability for a node to have a size and a pivot point.
 abstract class NodeWithSize extends Node {
 
   /// Changing the size will affect the size of the rendering of the node.
   ///
   ///     myNode.size = new Size(1024.0, 1024.0);
@@ skipping 14 matching lines @@
     if (size == null) size = Size.zero;
     if (pivot == null) pivot = Point.origin;
   }
 
   /// Call this method in your [paint] method if you want the origin of your drawing to be the top left corner of the
   /// node's bounding box.
   ///
   /// If you use this method you will need to save and restore your canvas at the beginning and
   /// end of your [paint] method.
   ///
-  ///     void paint(PictureRecorder canvas) {
+  ///     void paint(RenderCanvas canvas) {
   ///       canvas.save();
   ///       applyTransformForPivot(canvas);
   ///
   ///       // Do painting here
   ///
   ///       canvas.restore();
   ///     }
-  void applyTransformForPivot(PictureRecorder canvas) {
+  void applyTransformForPivot(RenderCanvas canvas) {
     if (pivot.x != 0 || pivot.y != 0) {
       double pivotInPointsX = size.width * pivot.x;
       double pivotInPointsY = size.height * pivot.y;
       canvas.translate(-pivotInPointsX, -pivotInPointsY);
     }
   }
 
   bool isPointInside (Point nodePoint) {
 
     double minX = -size.width * pivot.x;
     double minY = -size.height * pivot.y;
     double maxX = minX + size.width;
     double maxY = minY + size.height;
     return (nodePoint.x >= minX && nodePoint.x < maxX &&
             nodePoint.y >= minY && nodePoint.y < maxY);
   }
 }