case nil:
		src = &image.Uniform{C: color.RGBA{0x11, 0x22, 0x33, 0x44}}
	case color.CMYKModel:
		src1 := image.NewCMYK(image.Rect(0, 0, srcw, srch))
		for y := 0; y < srch; y++ {
			for x := 0; x < srcw; x++ {
				src1.SetCMYK(x, y, color.CMYK{
					uint8(13 * x % 0x100),
					uint8(11 * y % 0x100),
					uint8((11*x + 13*y) % 0x100),
					uint8((31*x + 37*y) % 0x100),
				})
			}
		}
		src = src1
	case color.GrayModel:

	i := p.PixOffset(x, y)
	s := p.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857
	s[0] = cc
	s[1] = mm
	s[2] = yy
	s[3] = kk
}

func (p *CMYK) SetCMYK(x, y int, c color.CMYK) {
	if !(Point{x, y}.In(p.Rect)) {
		return
	}
	i := p.PixOffset(x, y)
	s := p.Pix[i : i+4 : i+4] // Small cap improves performance, see https://golang.org/issue/27857
	s[0] = c.C

pkg image, method (*CMYK) ColorModel() color.Model
pkg image, method (*CMYK) Opaque() bool
pkg image, method (*CMYK) PixOffset(int, int) int
pkg image, method (*CMYK) Set(int, int, color.Color)
pkg image, method (*CMYK) SetCMYK(int, int, color.CMYK)
pkg image, method (*CMYK) SubImage(Rectangle) Image
pkg image, method (Rectangle) At(int, int) color.Color
pkg image, method (Rectangle) Bounds() Rectangle

		{"(*CMYK).ColorModel", Method, 5},
		{"(*CMYK).Opaque", Method, 5},
		{"(*CMYK).PixOffset", Method, 5},
		{"(*CMYK).RGBA64At", Method, 17},
		{"(*CMYK).Set", Method, 5},
		{"(*CMYK).SetCMYK", Method, 5},
		{"(*CMYK).SetRGBA64", Method, 17},
		{"(*CMYK).SubImage", Method, 5},
		{"(*Gray).At", Method, 0},
		{"(*Gray).Bounds", Method, 0},
		{"(*Gray).ColorModel", Method, 0},