How to makeImageSnapshot of specific layer index

[hungtooc]

I'm currently draw image at 1st layer, draw some paths on the 2nd layer. How to makeImageSnapshot only for 2nd layer?
Here is my short code:

const onDraw = useDrawCallback(
    (_canvas, info) => {
    // Draw Image on the first layer
    _canvas.drawImageRect(
      skimage,
      {
        x: 0,
        y: 0,
        width: skimage.width(),
        height: skimage.height(),
      },
      {
        x: my_x,
        y: my_x,
        width: my_width,
        height: my_height,
      },
      p,
    );
      let p = Skia.Paint();
      p.setAlphaf(0.5);
      p.setColorFilter(
        Skia.ColorFilter.MakeBlend(Skia.Color('red'), BlendMode.Modulate),
      );
      _canvas.saveLayer(p, {
          x: my_x,
        y: my_x,
        width: my_width,
        height: my_height,
      });
     // Draw some Paths on the second layer
_canvas.current?.drawPath(
          myPath1.current.path,
          myPath2.current.paint,
        );
_canvas.current?.drawPath(
          myPath1.current.path,
          myPath2.current.paint,
        );

return  (<SkiaView
                    ref={skDrawRef as RefObject<SkiaView>}
                    onDraw={onDraw}
                    style={{
                      // opacity: 0.5,
                      // height: VIEW_HEIGHT,
                      // width: VIEW_WIDTH,
                      flex: 1,
                      zIndex: 10,
                    }}
                  />)

thanks.