package draw_test

import (
	"fmt"
	"image"
	"image/color"
	"image/draw"
	"math"
)

func ExampleDrawer_floydSteinberg() {
	const width = 130
	const height = 50

	im := image.NewGray(image.Rectangle{Max: image.Point{X: width, Y: height}})
	for x := 0; x < width; x++ {
		for y := 0; y < height; y++ {
			dist := math.Sqrt(math.Pow(float64(x-width/2), 2)/3+math.Pow(float64(y-height/2), 2)) / (height / 1.5) * 255

	for i := 0; i < b.N; i++ {
		m.SetAlpha16(4, 5, c)
	}
}

func BenchmarkGrayAt(b *testing.B) {
	m := NewGray(Rect(0, 0, 10, 10))
	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		m.GrayAt(4, 5)
	}
}

func BenchmarkGraySetGray(b *testing.B) {
	m := NewGray(Rect(0, 0, 10, 10))
	c := color.Gray{0x13}
	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		m.SetGray(4, 5, c)
	}
}

			if err != nil {
				t.Fatal(err)
			}
			err = diff(convertToNRGBA(m0), m1)
			if err != nil {
				t.Error(err)
			}
		})
	}
}

func BenchmarkEncodeGray(b *testing.B) {
	img := image.NewGray(image.Rect(0, 0, 640, 480))
	b.SetBytes(640 * 480 * 1)
	b.ReportAllocs()
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		Encode(io.Discard, img)
	}
}

type pool struct {
	b *EncoderBuffer
}

					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:
		src1 := image.NewGray(image.Rect(0, 0, srcw, srch))
		for y := 0; y < srch; y++ {
			for x := 0; x < srcw; x++ {
				src1.SetGray(x, y, color.Gray{
					uint8((11*x + 13*y) % 0x100),
				})
			}
		}
		src = src1

			continue
		}
	}
}

// TestWriteGrayscale tests that a grayscale images survives a round-trip
// through encode/decode cycle.
func TestWriteGrayscale(t *testing.T) {
	m0 := image.NewGray(image.Rect(0, 0, 32, 32))
	for i := range m0.Pix {
		m0.Pix[i] = uint8(i)
	}
	var buf bytes.Buffer
	if err := Encode(&buf, m0, nil); err != nil {
		t.Fatal(err)
	}
	m1, err := Decode(&buf)

package jpeg

import (
	"image"
)

// makeImg allocates and initializes the destination image.
func (d *decoder) makeImg(mxx, myy int) {
	if d.nComp == 1 {
		m := image.NewGray(image.Rect(0, 0, 8*mxx, 8*myy))
		d.img1 = m.SubImage(image.Rect(0, 0, d.width, d.height)).(*image.Gray)
		return
	}

	h0 := d.comp[0].h
	v0 := d.comp[0].v
	hRatio := h0 / d.comp[1].h
	vRatio := v0 / d.comp[1].v

		Stride: p.Stride,
		Rect:   r,
	}
}

// Opaque scans the entire image and reports whether it is fully opaque.
func (p *Gray) Opaque() bool {
	return true
}

// NewGray returns a new [Gray] image with the given bounds.
func NewGray(r Rectangle) *Gray {
	return &Gray{
		Pix:    make([]uint8, pixelBufferLength(1, r, "Gray")),
		Stride: 1 * r.Dx(),
		Rect:   r,
	}
}

	}
	for y := 0; y < 16; y++ {
		for x := 0; x < 16; x++ {
			m.Cr[y*m.CStride+x] = uint8(y * 0x11)
		}
	}
	return m
}

func vgradGray() image.Image {
	m := image.NewGray(image.Rect(0, 0, 16, 16))
	for y := 0; y < 16; y++ {
		for x := 0; x < 16; x++ {
			m.Set(x, y, color.Gray{uint8(y * 0x11)})
		}
	}
	return m
}

func vgradMagenta() image.Image {

	}
	switch d.cb {
	case cbG1, cbG2, cbG4, cbG8:
		bitsPerPixel = d.depth
		if d.useTransparent {
			nrgba = image.NewNRGBA(image.Rect(0, 0, width, height))
			img = nrgba
		} else {
			gray = image.NewGray(image.Rect(0, 0, width, height))
			img = gray
		}
	case cbGA8:
		bitsPerPixel = 16
		nrgba = image.NewNRGBA(image.Rect(0, 0, width, height))
		img = nrgba
	case cbTC8:
		bitsPerPixel = 24

		{"NYCbCrA", Type, 6},
		{"NYCbCrA.A", Field, 6},
		{"NYCbCrA.AStride", Field, 6},
		{"NYCbCrA.YCbCr", Field, 6},
		{"NewAlpha", Func, 0},
		{"NewAlpha16", Func, 0},
		{"NewCMYK", Func, 5},
		{"NewGray", Func, 0},
		{"NewGray16", Func, 0},
		{"NewNRGBA", Func, 0},
		{"NewNRGBA64", Func, 0},
		{"NewNYCbCrA", Func, 6},
		{"NewPaletted", Func, 0},
		{"NewRGBA", Func, 0},
		{"NewRGBA64", Func, 0},