func (d *decoder) mergePassInto(dst image.Image, src image.Image, pass int) {
	p := interlacing[pass]
	var (
		srcPix        []uint8
		dstPix        []uint8
		stride        int
		rect          image.Rectangle
		bytesPerPixel int
	)
	switch target := dst.(type) {
	case *image.Alpha:
		srcPix = src.(*image.Alpha).Pix
		dstPix, stride, rect = target.Pix, target.Stride, target.Rect
		bytesPerPixel = 1

2B97          ; valid                  ;      ; NV8    # 13.0 SYMBOL FOR TYPE A ELECTRONICS
2B98..2BB9    ; valid                  ;      ; NV8    # 7.0  THREE-D TOP-LIGHTED LEFTWARDS EQUILATERAL ARROWHEAD..UP ARROWHEAD IN A RECTANGLE BOX
2BBA..2BBC    ; valid                  ;      ; NV8    # 11.0 OVERLAPPING WHITE SQUARES..OVERLAPPING BLACK SQUARES

static calculateRectsBasedSpeedIndex(timestampedPaintRects,viewport){const numberOfRects=timestampedPaintRects.length;if(numberOfRects===0){throw new Error('Can\'t calculate speed index without any paint '+'rectangles.');}