anchor.diff:  
       CanvasRenderingContext2D context2D = context.renderContext as CanvasRenderingContext2D;
   
  -    context2D.beginPath(); 
  -
       context2D.fillStyle = color.toString();
       
       _roundedRect(context2D, cornerX, cornerY, width, height, cornerRadius);
  
positive.code:     context.restore();
    }
  
    void _roundedRect(CanvasRenderingContext2D context, num cornerX, num cornerY, num width, num height, num cornerRadius) { 
      if (width > 0) 
        context.moveTo(cornerX + cornerRadius, cornerY); 
      else
  
negative.code:     else { 
        context.arcTo(cornerX, cornerY, cornerX - cornerRadius, cornerY, cornerRadius);
      }
      context.closePath();
    }
     
    Aabb2 get localBounds {
  