anchor.diff:    }
   
     void paint(Canvas canvas) {
  +    if (opacity == 0.0) return;
   
       List<ui.RSTransform> transforms = <ui.RSTransform>[];
       List<Rect> rects = <Rect>[];
  
positive.code: 
    double _emitCounter;
    int _numEmittedParticles = 0;
  
    static Paint _paint = new Paint()
      ..filterQuality = ui.FilterQuality.low
  
negative.code:         } else {
            particleColor = colorSequence.colorAtPosition(particle.colorPos);
          }
          if (opacity != 1.0) {
            particleColor = particleColor.withAlpha((particleColor.alpha * opacity).toInt().clamp(0, 255));
          }
          colors.add(particleColor);
        }
      }
  