anchor.diff:  // Use of this source code is governed by a BSD-style license that can be
   // found in the LICENSE file.
   
  +import 'dart:sky' as sky;
  +
   import 'package:sky/rendering.dart';
  +import 'package:sky/services.dart';
   import 'package:sky/src/fn3/framework.dart';
   
   export 'package:sky/rendering.dart' show
  
positive.code:   final BoxDecoration decoration;
    final BoxDecorationPosition position;
  
    RenderObject createRenderObject() => new RenderDecoratedBox(
      decoration: decoration,
      position: position
    );
  
    void updateRenderObject(RenderDecoratedBox renderObject) {
      renderObject.decoration = decoration;
      renderObject.position = position;
    }
  }
  
negative.code:     Size,
      ValueChanged;
  
  
  // PAINTING NODES
  
  class Opacity extends OneChildRenderObjectWidget {
    Opacity({ Key key, this.opacity, Widget child })
      : super(key: key, child: child) {
      assert(opacity >= 0.0 && opacity <= 1.0);
    }
  
    final double opacity;
  
    RenderOpacity createRenderObject() => new RenderOpacity(opacity: opacity);
  
    void updateRenderObject(RenderOpacity renderObject) {
      renderObject.opacity = opacity;
    }
  }
  
  class ColorFilter extends OneChildRenderObjectWidget {
    ColorFilter({ Key key, this.color, this.transferMode, Widget child })
      : super(key: key, child: child) {
      assert(color != null);
      assert(transferMode != null);
    }
  
    final Color color;
    final sky.TransferMode transferMode;
  
    RenderColorFilter createRenderObject() => new RenderColorFilter(color: color, transferMode: transferMode);
  
    void updateRenderObject(RenderColorFilter renderObject) {
      renderObject.color = color;
      renderObject.transferMode = transferMode;
    }
  }
  
  class DecoratedBox extends OneChildRenderObjectWidget {
    DecoratedBox({
      Key key,
  