anchor.diff:        idx += 5;
       }
   
  -    double colorOpacity = min(1.0, max(0.0, modulateOpacity*opacity));
       return ui.Paint()
  -      ..color = Colors.white.withOpacity(colorOpacity)
  +      ..color = Colors.white.withOpacity((modulateOpacity*opacity).clamp(0.0, 1.0))
         ..shader = ui.Gradient.radial(Offset(renderStart[0], renderStart[1]),
             radius, colors, stops, ui.TileMode.clamp) //, transform.mat4)
         // ..shader = new ui.Gradient.radial(new ui.Offset(center[0], center[1]), radius, colors, stops)
  
positive.code:         stops,
          ui.TileMode.clamp); //, transform.mat4);
  
      double colorOpacity = min(1.0, max(0.0, modulateOpacity*opacity));
      ui.Paint paint = ui.Paint()
        ..color = Colors.white.withOpacity(colorOpacity)
        ..shader = radial
        ..style = ui.PaintingStyle.fill;
  
  
negative.code:       idx += 5;
      }
  
      ui.Paint paint = ui.Paint()
        ..color = Colors.white.withOpacity((modulateOpacity*opacity).clamp(0.0, 1.0))
        ..shader = ui.Gradient.linear(ui.Offset(renderStart[0], renderStart[1]),
            ui.Offset(renderEnd[0], renderEnd[1]), colors, stops)
        ..strokeWidth = width
  