mirror of
https://github.com/esimov/caire.git
synced 2024-05-31 14:55:55 +08:00
231 lines
5.3 KiB
Go
231 lines
5.3 KiB
Go
package caire
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import (
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"image"
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"image/color"
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"image/color/palette"
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"image/draw"
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"io/ioutil"
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"path/filepath"
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"testing"
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"github.com/esimov/caire/utils"
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)
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func TestImage_ShouldGetSampleImage(t *testing.T) {
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path := filepath.Join("./testdata", "sample.jpg")
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_, err := ioutil.ReadFile(path)
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if err != nil {
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t.Errorf("Should get the sample image")
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}
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}
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func TestImage_ImgToNRGBA(t *testing.T) {
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rect := image.Rect(-1, -1, 15, 15)
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colors := palette.Plan9
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testCases := []struct {
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name string
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img image.Image
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}{
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{
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name: "NRGBA",
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img: makeNRGBAImage(rect, colors),
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},
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{
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name: "YCbCr-444",
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img: makeYCbCrImage(rect, colors, image.YCbCrSubsampleRatio444),
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},
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{
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name: "YCbCr-422",
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img: makeYCbCrImage(rect, colors, image.YCbCrSubsampleRatio422),
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},
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{
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name: "YCbCr-420",
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img: makeYCbCrImage(rect, colors, image.YCbCrSubsampleRatio420),
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},
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{
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name: "YCbCr-440",
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img: makeYCbCrImage(rect, colors, image.YCbCrSubsampleRatio440),
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},
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{
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name: "YCbCr-410",
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img: makeYCbCrImage(rect, colors, image.YCbCrSubsampleRatio410),
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},
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{
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name: "YCbCr-411",
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img: makeYCbCrImage(rect, colors, image.YCbCrSubsampleRatio411),
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},
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}
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for _, tc := range testCases {
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t.Run(tc.name, func(t *testing.T) {
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r := tc.img.Bounds()
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for y := r.Min.Y; y < r.Max.Y; y++ {
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buf := make([]byte, r.Dx()*4)
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scan(tc.img, 0, y-r.Min.Y, r.Dx(), y+1-r.Min.Y, buf)
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wantBuf := readRow(tc.img, y)
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if !compareBytes(buf, wantBuf, 1) {
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t.Errorf("scan horizontal line (y=%d): got %v want %v", y, buf, wantBuf)
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}
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}
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for x := r.Min.X; x < r.Max.X; x++ {
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buf := make([]byte, r.Dy()*4)
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scan(tc.img, x-r.Min.X, 0, x+1-r.Min.X, r.Dy(), buf)
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wantBuf := readColumn(tc.img, x)
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if !compareBytes(buf, wantBuf, 1) {
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t.Errorf("scan vertical line (x=%d): got %v want %v", x, buf, wantBuf)
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}
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}
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})
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}
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}
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func scan(img image.Image, x1, y1, x2, y2 int, dst []uint8) {
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switch img := img.(type) {
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case *image.NRGBA:
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size := (x2 - x1) * 4
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j := 0
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i := y1*img.Stride + x1*4
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for y := y1; y < y2; y++ {
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copy(dst[j:j+size], img.Pix[i:i+size])
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j += size
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i += img.Stride
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}
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case *image.YCbCr:
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j := 0
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x1 += img.Rect.Min.X
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x2 += img.Rect.Min.X
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y1 += img.Rect.Min.Y
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y2 += img.Rect.Min.Y
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for y := y1; y < y2; y++ {
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iy := (y-img.Rect.Min.Y)*img.YStride + (x1 - img.Rect.Min.X)
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for x := x1; x < x2; x++ {
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var ic int
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switch img.SubsampleRatio {
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case image.YCbCrSubsampleRatio444:
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ic = (y-img.Rect.Min.Y)*img.CStride + (x - img.Rect.Min.X)
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case image.YCbCrSubsampleRatio422:
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ic = (y-img.Rect.Min.Y)*img.CStride + (x/2 - img.Rect.Min.X/2)
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case image.YCbCrSubsampleRatio420:
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ic = (y/2-img.Rect.Min.Y/2)*img.CStride + (x/2 - img.Rect.Min.X/2)
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case image.YCbCrSubsampleRatio440:
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ic = (y/2-img.Rect.Min.Y/2)*img.CStride + (x - img.Rect.Min.X)
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default:
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ic = img.COffset(x, y)
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}
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yy := int(img.Y[iy])
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cb := int(img.Cb[ic]) - 128
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cr := int(img.Cr[ic]) - 128
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r := (yy<<16 + 91881*cr + 1<<15) >> 16
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if r > 0xff {
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r = 0xff
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} else if r < 0 {
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r = 0
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}
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g := (yy<<16 - 22554*cb - 46802*cr + 1<<15) >> 16
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if g > 0xff {
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g = 0xff
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} else if g < 0 {
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g = 0
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}
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b := (yy<<16 + 116130*cb + 1<<15) >> 16
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if b > 0xff {
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b = 0xff
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} else if b < 0 {
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b = 0
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}
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dst[j+0] = uint8(r)
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dst[j+1] = uint8(g)
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dst[j+2] = uint8(b)
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dst[j+3] = 0xff
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iy++
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j += 4
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}
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}
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}
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}
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func makeYCbCrImage(rect image.Rectangle, colors []color.Color, sr image.YCbCrSubsampleRatio) *image.YCbCr {
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img := image.NewYCbCr(rect, sr)
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j := 0
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for y := rect.Min.Y; y < rect.Max.Y; y++ {
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for x := rect.Min.X; x < rect.Max.X; x++ {
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iy := img.YOffset(x, y)
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ic := img.COffset(x, y)
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c := color.NRGBAModel.Convert(colors[j]).(color.NRGBA)
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img.Y[iy], img.Cb[ic], img.Cr[ic] = color.RGBToYCbCr(c.R, c.G, c.B)
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j++
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}
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}
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return img
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}
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func makeNRGBAImage(rect image.Rectangle, colors []color.Color) *image.NRGBA {
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img := image.NewNRGBA(rect)
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fillDrawImage(img, colors)
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return img
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}
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func fillDrawImage(img draw.Image, colors []color.Color) {
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colorsNRGBA := make([]color.NRGBA, len(colors))
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for i, c := range colors {
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nrgba := color.NRGBAModel.Convert(c).(color.NRGBA)
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nrgba.A = uint8(i % 256)
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colorsNRGBA[i] = nrgba
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}
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rect := img.Bounds()
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i := 0
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for y := rect.Min.Y; y < rect.Max.Y; y++ {
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for x := rect.Min.X; x < rect.Max.X; x++ {
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img.Set(x, y, colorsNRGBA[i])
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i++
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}
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}
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}
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func readRow(img image.Image, y int) []uint8 {
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row := make([]byte, img.Bounds().Dx()*4)
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i := 0
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for x := img.Bounds().Min.X; x < img.Bounds().Max.X; x++ {
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c := color.NRGBAModel.Convert(img.At(x, y)).(color.NRGBA)
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row[i+0] = c.R
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row[i+1] = c.G
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row[i+2] = c.B
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row[i+3] = c.A
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i += 4
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}
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return row
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}
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func readColumn(img image.Image, x int) []uint8 {
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column := make([]byte, img.Bounds().Dy()*4)
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i := 0
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for y := img.Bounds().Min.Y; y < img.Bounds().Max.Y; y++ {
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c := color.NRGBAModel.Convert(img.At(x, y)).(color.NRGBA)
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column[i+0] = c.R
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column[i+1] = c.G
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column[i+2] = c.B
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column[i+3] = c.A
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i += 4
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}
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return column
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}
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func compareBytes(a, b []uint8, delta int) bool {
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if len(a) != len(b) {
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return false
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}
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for i := 0; i < len(a); i++ {
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if utils.Abs(int(a[i])-int(b[i])) > delta {
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return false
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}
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}
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return true
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}
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