func BenchmarkYCbCr(b *testing.B) {
	bench(b, color.RGBAModel, color.YCbCrModel, nil, Over)
}

func BenchmarkGray(b *testing.B) {
	bench(b, color.RGBAModel, color.GrayModel, nil, Over)
}

func BenchmarkCMYK(b *testing.B) {
	bench(b, color.RGBAModel, color.CMYKModel, nil, Over)
}

func BenchmarkGlyphOver(b *testing.B) {
	bench(b, color.RGBAModel, nil, color.AlphaModel, Over)
}