if m0.Bounds() != image.Rect(0, 0, 150, 103) {
			t.Errorf("%s: bad bounds: %v", tc, m0.Bounds())
			continue
		}

		switch m0 := m0.(type) {
		case *image.YCbCr:
			m1 := m1.(*image.YCbCr)
			if err := check(m0.Bounds(), m0.Y, m1.Y, m0.YStride, m1.YStride); err != nil {
				t.Errorf("%s (Y): %v", tc, err)
				continue
			}

		subsampleRatio = image.YCbCrSubsampleRatio410
	default:
		panic("unreachable")
	}
	m := image.NewYCbCr(image.Rect(0, 0, 8*h0*mxx, 8*v0*myy), subsampleRatio)
	d.img3 = m.SubImage(image.Rect(0, 0, d.width, d.height)).(*image.YCbCr)

	if d.nComp == 4 {
		h3, v3 := d.comp[3].h, d.comp[3].v
		d.blackPix = make([]byte, 8*h3*mxx*8*v3*myy)
		d.blackStride = 8 * h3 * mxx
	}
}

// Specified in section B.2.3.

					}
					return
				case *image.RGBA:
					drawCopyOver(dst0, r, src0, sp)
					return
				case *image.NRGBA:
					drawNRGBAOver(dst0, r, src0, sp)
					return
				case *image.YCbCr:
					// An image.YCbCr is always fully opaque, and so if the
					// mask is nil (i.e. fully opaque) then the op is
					// effectively always Src. Similarly for image.Gray and
					// image.CMYK.

		{"(*Uniform).RGBA64At", Method, 17},
		{"(*YCbCr).At", Method, 0},
		{"(*YCbCr).Bounds", Method, 0},
		{"(*YCbCr).COffset", Method, 0},
		{"(*YCbCr).ColorModel", Method, 0},
		{"(*YCbCr).Opaque", Method, 0},
		{"(*YCbCr).RGBA64At", Method, 17},
		{"(*YCbCr).SubImage", Method, 0},
		{"(*YCbCr).YCbCrAt", Method, 4},
		{"(*YCbCr).YOffset", Method, 0},
		{"(Point).Add", Method, 0},