016a61cd31
This is a complete rewrite! The tight scaling loop needs data locality for optimal performance. The old version used lots of pointer redirections to access image data which was bad for data locality. By providing the complete loop for each image type, this problem is solved. Unfortunately this increases code duplication but the result should be worth it: I could measure a ~6x speed-up for certain test cases!
257 lines
7.7 KiB
Go
257 lines
7.7 KiB
Go
/*
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Copyright (c) 2012, Jan Schlicht <jan.schlicht@gmail.com>
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Permission to use, copy, modify, and/or distribute this software for any purpose
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with or without fee is hereby granted, provided that the above copyright notice
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and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
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REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
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INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
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OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
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THIS SOFTWARE.
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*/
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package resize
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import (
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"image"
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"image/color"
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)
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// Keep value in [0,255] range.
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func clampUint8(in int32) uint8 {
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if in < 0 {
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return 0
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}
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if in > 255 {
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return 255
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}
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return uint8(in)
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}
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// Keep value in [0,65535] range.
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func clampUint16(in int64) uint16 {
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if in < 0 {
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return 0
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}
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if in > 65535 {
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return 65535
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}
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return uint16(in)
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}
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func resizeGeneric(in image.Image, out *image.RGBA64, scale float64, coeffs []int32, 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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interpX := scale*(float64(y)+0.5) + float64(oldBounds.Min.X)
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start := int(interpX) - filterLength/2 + 1
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var rgba [4]int64
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var sum int64
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for i := 0; i < filterLength; i++ {
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xx := start + i
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if xx < oldBounds.Min.X {
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xx = oldBounds.Min.X
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} else if xx >= oldBounds.Max.X {
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xx = oldBounds.Max.X - 1
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}
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coeff := coeffs[(y-newBounds.Min.Y)*filterLength+i]
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r, g, b, a := in.At(xx, x).RGBA()
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rgba[0] += int64(coeff) * int64(r)
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rgba[1] += int64(coeff) * int64(g)
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rgba[2] += int64(coeff) * int64(b)
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rgba[3] += int64(coeff) * int64(a)
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sum += int64(coeff)
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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 := clampUint16(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 = clampUint16(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 = clampUint16(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 = clampUint16(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 resizeRGBA(in *image.RGBA, out *image.RGBA, scale float64, coeffs []int16, 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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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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interpX := scale*(float64(y)+0.5) + float64(oldBounds.Min.X)
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start := int(interpX) - filterLength/2 + 1
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var rgba [4]int32
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var sum int32
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for i := 0; i < filterLength; i++ {
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xx := start + i
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if xx < oldBounds.Min.X {
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xx = oldBounds.Min.X
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} else if xx >= oldBounds.Max.X {
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xx = oldBounds.Max.X - 1
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}
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coeff := coeffs[(y-newBounds.Min.Y)*filterLength+i]
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offset := (xx - oldBounds.Min.X) * 4
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rgba[0] += int32(coeff) * int32(row[offset+0])
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rgba[1] += int32(coeff) * int32(row[offset+1])
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rgba[2] += int32(coeff) * int32(row[offset+2])
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rgba[3] += int32(coeff) * int32(row[offset+3])
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sum += int32(coeff)
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}
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offset := (y-newBounds.Min.Y)*out.Stride + (x-newBounds.Min.X)*4
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out.Pix[offset+0] = clampUint8(rgba[0] / sum)
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out.Pix[offset+1] = clampUint8(rgba[1] / sum)
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out.Pix[offset+2] = clampUint8(rgba[2] / sum)
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out.Pix[offset+3] = clampUint8(rgba[3] / sum)
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}
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}
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}
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func resizeRGBA64(in *image.RGBA64, out *image.RGBA64, scale float64, coeffs []int32, 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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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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interpX := scale*(float64(y)+0.5) + float64(oldBounds.Min.X)
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start := int(interpX) - filterLength/2 + 1
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var rgba [4]int64
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var sum int64
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for i := 0; i < filterLength; i++ {
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xx := start + i
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if xx < oldBounds.Min.X {
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xx = oldBounds.Min.X
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} else if xx >= oldBounds.Max.X {
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xx = oldBounds.Max.X - 1
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}
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coeff := coeffs[(y-newBounds.Min.Y)*filterLength+i]
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offset := (xx - oldBounds.Min.X) * 8
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rgba[0] += int64(coeff) * int64(uint16(row[offset+0])<<8|uint16(row[offset+1]))
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rgba[1] += int64(coeff) * int64(uint16(row[offset+2])<<8|uint16(row[offset+3]))
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rgba[2] += int64(coeff) * int64(uint16(row[offset+4])<<8|uint16(row[offset+5]))
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rgba[3] += int64(coeff) * int64(uint16(row[offset+6])<<8|uint16(row[offset+7]))
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sum += int64(coeff)
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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 := clampUint16(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 = clampUint16(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 = clampUint16(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 = clampUint16(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 resizeGray(in *image.Gray, out *image.Gray, scale float64, coeffs []int16, 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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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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interpX := scale*(float64(y)+0.5) + float64(oldBounds.Min.X)
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start := int(interpX) - filterLength/2 + 1
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var gray int32
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var sum int32
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for i := 0; i < filterLength; i++ {
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xx := start + i
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if xx < oldBounds.Min.X {
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xx = oldBounds.Min.X
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} else if xx >= oldBounds.Max.X {
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xx = oldBounds.Max.X - 1
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}
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coeff := coeffs[(y-newBounds.Min.Y)*filterLength+i]
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offset := (xx - oldBounds.Min.X)
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gray += int32(coeff) * int32(row[offset])
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sum += int32(coeff)
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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] = clampUint8(gray / sum)
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}
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}
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}
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func resizeGray16(in *image.Gray16, out *image.Gray16, scale float64, coeffs []int32, 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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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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interpX := scale*(float64(y)+0.5) + float64(oldBounds.Min.X)
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start := int(interpX) - filterLength/2 + 1
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var gray int64
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var sum int64
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for i := 0; i < filterLength; i++ {
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xx := start + i
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if xx < oldBounds.Min.X {
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xx = oldBounds.Min.X
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} else if xx >= oldBounds.Max.X {
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xx = oldBounds.Max.X - 1
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}
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coeff := coeffs[(y-newBounds.Min.Y)*filterLength+i]
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offset := (xx - oldBounds.Min.X) * 2
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gray += int64(coeff) * int64(uint16(row[offset+0])<<8|uint16(row[offset+1]))
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sum += int64(coeff)
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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 := clampUint16(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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func convertYCbCrToRGBA(in *image.YCbCr) *image.RGBA {
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out := image.NewRGBA(in.Bounds())
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for y := 0; y < out.Bounds().Dy(); y++ {
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for x := 0; x < out.Bounds().Dx(); x++ {
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p := out.Pix[y*out.Stride+4*x:]
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yi := in.YOffset(x, y)
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ci := in.COffset(x, y)
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r, g, b := color.YCbCrToRGB(in.Y[yi], in.Cb[ci], in.Cr[ci])
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p[0] = r
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p[1] = g
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p[2] = b
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p[3] = 0xff
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}
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}
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return out
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}
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