anchor.diff:      assert(debugCanPaintChild(child));
       final Offset childOffset = childPosition.toOffset();
       if (!child.needsCompositing) {
  -      canvas.saveLayer(bounds, OpacityLayer.paintForAlpha(alpha));
  +      canvas.saveLayer(bounds, _getPaintForAlpha(alpha));
         canvas.translate(childOffset.dx, childOffset.dy);
         insertChild(child, Offset.zero);
         canvas.restore();
  
positive.code:       _containerLayer.add(paintLayer);
        compositeChild(child, parentLayer: paintLayer);
      }
    }
  
    void paintChildWithColorFilter(RenderObject child,
  
negative.code:     assert(debugCanPaintChild(child));
      final Offset childOffset = childPosition.toOffset();
      if (!child.needsCompositing) {
        canvas.saveLayer(bounds, _getPaintForColorFilter(color, transferMode));
        canvas.translate(childOffset.dx, childOffset.dy);
        insertChild(child, Offset.zero);
        canvas.restore();
  