229 lines
6.2 KiB
Go
229 lines
6.2 KiB
Go
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package resize
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import "image"
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func floatToUint8(x float32) uint8 {
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// Nearest-neighbor values are always
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// positive no need to check lower-bound.
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if x > 0xfe {
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return 0xff
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}
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return uint8(x)
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}
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func floatToUint16(x float32) uint16 {
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if x > 0xfffe {
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return 0xffff
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}
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return uint16(x)
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}
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func nearestGeneric(in image.Image, out *image.RGBA64, scale float64, coeffs []bool, offset []int, filterLength int) {
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oldBounds := in.Bounds()
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newBounds := out.Bounds()
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for x := newBounds.Min.X; x < newBounds.Max.X; x++ {
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for y := newBounds.Min.Y; y < newBounds.Max.Y; y++ {
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var rgba [4]float32
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var sum float32
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start := offset[y]
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ci := (y - newBounds.Min.Y) * filterLength
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for i := 0; i < filterLength; i++ {
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if coeffs[ci+i] {
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xi := start + i
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switch {
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case uint(xi) < uint(oldBounds.Max.X):
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break
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case xi >= oldBounds.Max.X:
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xi = oldBounds.Min.X
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default:
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xi = oldBounds.Max.X - 1
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}
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r, g, b, a := in.At(xi, x).RGBA()
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rgba[0] += float32(r)
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rgba[1] += float32(g)
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rgba[2] += float32(b)
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rgba[3] += float32(a)
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sum++
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}
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}
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offset := (y-newBounds.Min.Y)*out.Stride + (x-newBounds.Min.X)*8
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value := floatToUint16(rgba[0] / sum)
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out.Pix[offset+0] = uint8(value >> 8)
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out.Pix[offset+1] = uint8(value)
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value = floatToUint16(rgba[1] / sum)
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out.Pix[offset+2] = uint8(value >> 8)
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out.Pix[offset+3] = uint8(value)
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value = floatToUint16(rgba[2] / sum)
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out.Pix[offset+4] = uint8(value >> 8)
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out.Pix[offset+5] = uint8(value)
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value = floatToUint16(rgba[3] / sum)
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out.Pix[offset+6] = uint8(value >> 8)
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out.Pix[offset+7] = uint8(value)
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}
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}
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}
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func nearestRGBA(in *image.RGBA, out *image.RGBA, scale float64, coeffs []bool, offset []int, filterLength int) {
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oldBounds := in.Bounds()
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newBounds := out.Bounds()
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minX := oldBounds.Min.X * 4
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maxX := (oldBounds.Max.X - oldBounds.Min.X - 1) * 4
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for x := newBounds.Min.X; x < newBounds.Max.X; x++ {
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row := in.Pix[(x-oldBounds.Min.Y)*in.Stride:]
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for y := newBounds.Min.Y; y < newBounds.Max.Y; y++ {
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var rgba [4]float32
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var sum float32
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start := offset[y]
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ci := (y - newBounds.Min.Y) * filterLength
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for i := 0; i < filterLength; i++ {
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if coeffs[ci+i] {
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xi := start + i
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switch {
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case uint(xi) < uint(oldBounds.Max.X):
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xi *= 4
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case xi >= oldBounds.Max.X:
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xi = maxX
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default:
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xi = minX
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}
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rgba[0] += float32(row[xi+0])
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rgba[1] += float32(row[xi+1])
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rgba[2] += float32(row[xi+2])
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rgba[3] += float32(row[xi+3])
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sum++
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}
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}
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xo := (y-newBounds.Min.Y)*out.Stride + (x-newBounds.Min.X)*4
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out.Pix[xo+0] = floatToUint8(rgba[0] / sum)
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out.Pix[xo+1] = floatToUint8(rgba[1] / sum)
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out.Pix[xo+2] = floatToUint8(rgba[2] / sum)
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out.Pix[xo+3] = floatToUint8(rgba[3] / sum)
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}
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}
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}
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func nearestRGBA64(in *image.RGBA64, out *image.RGBA64, scale float64, coeffs []bool, offset []int, filterLength int) {
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oldBounds := in.Bounds()
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newBounds := out.Bounds()
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minX := oldBounds.Min.X * 8
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maxX := (oldBounds.Max.X - oldBounds.Min.X - 1) * 8
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for x := newBounds.Min.X; x < newBounds.Max.X; x++ {
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row := in.Pix[(x-oldBounds.Min.Y)*in.Stride:]
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for y := newBounds.Min.Y; y < newBounds.Max.Y; y++ {
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var rgba [4]float32
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var sum float32
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start := offset[y]
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ci := (y - newBounds.Min.Y) * filterLength
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for i := 0; i < filterLength; i++ {
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if coeffs[ci+i] {
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xi := start + i
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switch {
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case uint(xi) < uint(oldBounds.Max.X):
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xi *= 8
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case xi >= oldBounds.Max.X:
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xi = maxX
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default:
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xi = minX
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}
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rgba[0] += float32(uint16(row[xi+0])<<8 | uint16(row[xi+1]))
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rgba[1] += float32(uint16(row[xi+2])<<8 | uint16(row[xi+3]))
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rgba[2] += float32(uint16(row[xi+4])<<8 | uint16(row[xi+5]))
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rgba[3] += float32(uint16(row[xi+6])<<8 | uint16(row[xi+7]))
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sum++
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}
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}
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xo := (y-newBounds.Min.Y)*out.Stride + (x-newBounds.Min.X)*8
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value := floatToUint16(rgba[0] / sum)
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out.Pix[xo+0] = uint8(value >> 8)
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out.Pix[xo+1] = uint8(value)
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value = floatToUint16(rgba[1] / sum)
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out.Pix[xo+2] = uint8(value >> 8)
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out.Pix[xo+3] = uint8(value)
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value = floatToUint16(rgba[2] / sum)
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out.Pix[xo+4] = uint8(value >> 8)
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out.Pix[xo+5] = uint8(value)
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value = floatToUint16(rgba[3] / sum)
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out.Pix[xo+6] = uint8(value >> 8)
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out.Pix[xo+7] = uint8(value)
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}
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}
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}
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func nearestGray(in *image.Gray, out *image.Gray, scale float64, coeffs []bool, offset []int, filterLength int) {
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oldBounds := in.Bounds()
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newBounds := out.Bounds()
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minX := oldBounds.Min.X
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maxX := (oldBounds.Max.X - oldBounds.Min.X - 1)
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for x := newBounds.Min.X; x < newBounds.Max.X; x++ {
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row := in.Pix[(x-oldBounds.Min.Y)*in.Stride:]
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for y := newBounds.Min.Y; y < newBounds.Max.Y; y++ {
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var gray float32
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var sum float32
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start := offset[y]
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ci := (y - newBounds.Min.Y) * filterLength
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for i := 0; i < filterLength; i++ {
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if coeffs[ci+i] {
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xi := start + i
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switch {
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case uint(xi) < uint(oldBounds.Max.X):
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break
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case xi >= oldBounds.Max.X:
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xi = maxX
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default:
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xi = minX
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}
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gray += float32(row[xi])
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sum++
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}
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}
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offset := (y-newBounds.Min.Y)*out.Stride + (x - newBounds.Min.X)
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out.Pix[offset] = floatToUint8(gray / sum)
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}
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}
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}
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func nearestGray16(in *image.Gray16, out *image.Gray16, scale float64, coeffs []bool, offset []int, filterLength int) {
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oldBounds := in.Bounds()
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newBounds := out.Bounds()
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minX := oldBounds.Min.X * 2
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maxX := (oldBounds.Max.X - oldBounds.Min.X - 1) * 2
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for x := newBounds.Min.X; x < newBounds.Max.X; x++ {
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row := in.Pix[(x-oldBounds.Min.Y)*in.Stride:]
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for y := newBounds.Min.Y; y < newBounds.Max.Y; y++ {
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var gray float32
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var sum float32
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start := offset[y]
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ci := (y - newBounds.Min.Y) * filterLength
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for i := 0; i < filterLength; i++ {
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if coeffs[ci+i] {
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xi := start + i
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switch {
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case uint(xi) < uint(oldBounds.Max.X):
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xi *= 2
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case xi >= oldBounds.Max.X:
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xi = maxX
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default:
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xi = minX
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}
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gray += float32(uint16(row[xi+0])<<8 | uint16(row[xi+1]))
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sum++
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}
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}
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offset := (y-newBounds.Min.Y)*out.Stride + (x-newBounds.Min.X)*2
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value := floatToUint16(gray / sum)
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out.Pix[offset+0] = uint8(value >> 8)
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out.Pix[offset+1] = uint8(value)
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}
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}
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}
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