Optimize YCbCr image resize
Charlie Vieth
parent
427b8d133e
commit
eefd4737aa
93
converter.go
93
converter.go
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@ -16,10 +16,7 @@ THIS SOFTWARE.
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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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import "image"
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// Keep value in [0,255] range.
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func clampUint8(in int32) uint8 {
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@ -257,19 +254,81 @@ func resizeGray16(in *image.Gray16, out *image.Gray16, scale float64, coeffs []i
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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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func resizeYCbCr(in *ycc, out *ycc, scale float64, coeffs []int16, 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 * 3
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maxX := (oldBounds.Max.X - oldBounds.Min.X - 1) * 3
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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 p [3]int32
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var sum int32
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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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coeff := coeffs[ci+i]
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if coeff != 0 {
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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 *= 3
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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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p[0] += int32(coeff) * int32(row[xi+0])
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p[1] += int32(coeff) * int32(row[xi+1])
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p[2] += int32(coeff) * int32(row[xi+2])
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sum += int32(coeff)
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}
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}
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xo := (y-newBounds.Min.Y)*out.Stride + (x-newBounds.Min.X)*3
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out.Pix[xo+0] = clampUint8(p[0] / sum)
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out.Pix[xo+1] = clampUint8(p[1] / sum)
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out.Pix[xo+2] = clampUint8(p[2] / sum)
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}
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}
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}
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func nearestYCbCr(in *ycc, out *ycc, 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 * 3
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maxX := (oldBounds.Max.X - oldBounds.Min.X - 1) * 3
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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 p [3]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 *= 3
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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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p[0] += float32(row[xi+0])
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p[1] += float32(row[xi+1])
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p[2] += float32(row[xi+2])
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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)*3
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out.Pix[xo+0] = floatToUint8(p[0] / sum)
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out.Pix[xo+1] = floatToUint8(p[1] / sum)
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out.Pix[xo+2] = floatToUint8(p[2] / sum)
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}
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}
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return out
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}
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16
nearest.go
16
nearest.go
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@ -1,3 +1,19 @@
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/*
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Copyright (c) 2014, Charlie Vieth <charlie.vieth@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 "image"
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@ -1,3 +1,19 @@
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/*
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Copyright (c) 2014, Charlie Vieth <charlie.vieth@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 "testing"
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40
resize.go
40
resize.go
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@ -129,35 +129,33 @@ func Resize(width, height uint, img image.Image, interp InterpolationFunction) i
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case *image.YCbCr:
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// 8-bit precision
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// accessing the YCbCr arrays in a tight loop is slow.
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// converting the image before filtering will improve performance.
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inputAsRGBA := convertYCbCrToRGBA(input)
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temp := image.NewRGBA(image.Rect(0, 0, input.Bounds().Dy(), int(width)))
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result := image.NewRGBA(image.Rect(0, 0, int(width), int(height)))
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// converting the image to ycc increases performance by 2x.
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temp := newYCC(image.Rect(0, 0, input.Bounds().Dy(), int(width)), input.SubsampleRatio)
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result := newYCC(image.Rect(0, 0, int(width), int(height)), input.SubsampleRatio)
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// horizontal filter, results in transposed temporary image
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coeffs, offset, filterLength := createWeights8(temp.Bounds().Dy(), input.Bounds().Min.X, taps, blur, scaleX, kernel)
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in := imageYCbCrToYCC(input)
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wg.Add(cpus)
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for i := 0; i < cpus; i++ {
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slice := makeSlice(temp, i, cpus).(*image.RGBA)
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slice := makeSlice(temp, i, cpus).(*ycc)
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go func() {
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defer wg.Done()
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resizeRGBA(inputAsRGBA, slice, scaleX, coeffs, offset, filterLength)
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resizeYCbCr(in, slice, scaleX, coeffs, offset, filterLength)
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}()
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}
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wg.Wait()
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// horizontal filter on transposed image, result is not transposed
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coeffs, offset, filterLength = createWeights8(result.Bounds().Dy(), temp.Bounds().Min.X, taps, blur, scaleY, kernel)
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wg.Add(cpus)
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for i := 0; i < cpus; i++ {
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slice := makeSlice(result, i, cpus).(*image.RGBA)
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slice := makeSlice(result, i, cpus).(*ycc)
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go func() {
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defer wg.Done()
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resizeRGBA(temp, slice, scaleY, coeffs, offset, filterLength)
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resizeYCbCr(temp, slice, scaleY, coeffs, offset, filterLength)
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}()
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}
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wg.Wait()
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return result
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return result.YCbCr()
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case *image.RGBA64:
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// 16-bit precision
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temp := image.NewRGBA64(image.Rect(0, 0, input.Bounds().Dy(), int(width)))
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@ -315,35 +313,33 @@ func resizeNearest(width, height uint, scaleX, scaleY float64, img image.Image,
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case *image.YCbCr:
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// 8-bit precision
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// accessing the YCbCr arrays in a tight loop is slow.
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// converting the image before filtering will improve performance.
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inputAsRGBA := convertYCbCrToRGBA(input)
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temp := image.NewRGBA(image.Rect(0, 0, input.Bounds().Dy(), int(width)))
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result := image.NewRGBA(image.Rect(0, 0, int(width), int(height)))
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// converting the image to ycc increases performance by 2x.
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temp := newYCC(image.Rect(0, 0, input.Bounds().Dy(), int(width)), input.SubsampleRatio)
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result := newYCC(image.Rect(0, 0, int(width), int(height)), input.SubsampleRatio)
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// horizontal filter, results in transposed temporary image
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coeffs, offset, filterLength := createWeightsNearest(temp.Bounds().Dy(), input.Bounds().Min.X, taps, blur, scaleX)
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in := imageYCbCrToYCC(input)
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wg.Add(cpus)
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for i := 0; i < cpus; i++ {
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slice := makeSlice(temp, i, cpus).(*image.RGBA)
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slice := makeSlice(temp, i, cpus).(*ycc)
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go func() {
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defer wg.Done()
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nearestRGBA(inputAsRGBA, slice, scaleX, coeffs, offset, filterLength)
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nearestYCbCr(in, slice, scaleX, coeffs, offset, filterLength)
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}()
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}
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wg.Wait()
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// horizontal filter on transposed image, result is not transposed
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coeffs, offset, filterLength = createWeightsNearest(result.Bounds().Dy(), temp.Bounds().Min.X, taps, blur, scaleY)
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wg.Add(cpus)
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for i := 0; i < cpus; i++ {
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slice := makeSlice(result, i, cpus).(*image.RGBA)
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slice := makeSlice(result, i, cpus).(*ycc)
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go func() {
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defer wg.Done()
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nearestRGBA(temp, slice, scaleY, coeffs, offset, filterLength)
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nearestYCbCr(temp, slice, scaleY, coeffs, offset, filterLength)
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}()
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}
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wg.Wait()
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return result
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return result.YCbCr()
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case *image.RGBA64:
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// 16-bit precision
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temp := image.NewRGBA64(image.Rect(0, 0, input.Bounds().Dy(), int(width)))
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@ -0,0 +1,226 @@
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/*
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Copyright (c) 2014, Charlie Vieth <charlie.vieth@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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// ycc is an in memory YCbCr image. The Y, Cb and Cr samples are held in a
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// single slice to increase resizing performance.
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type ycc struct {
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// Pix holds the image's pixels, in Y, Cb, Cr order. The pixel at
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// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*3].
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Pix []uint8
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// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
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Stride int
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// Rect is the image's bounds.
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Rect image.Rectangle
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// SubsampleRatio is the subsample ratio of the original YCbCr image.
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SubsampleRatio image.YCbCrSubsampleRatio
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}
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// PixOffset returns the index of the first element of Pix that corresponds to
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// the pixel at (x, y).
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func (p *ycc) PixOffset(x, y int) int {
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return (y * p.Stride) + (x * 3)
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}
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func (p *ycc) Bounds() image.Rectangle {
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return p.Rect
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}
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func (p *ycc) ColorModel() color.Model {
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return color.YCbCrModel
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}
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func (p *ycc) At(x, y int) color.Color {
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if !(image.Point{x, y}.In(p.Rect)) {
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return color.YCbCr{}
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}
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i := p.PixOffset(x, y)
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return color.YCbCr{
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p.Pix[i+0],
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p.Pix[i+1],
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p.Pix[i+2],
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}
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}
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func (p *ycc) Opaque() bool {
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return true
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}
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// SubImage returns an image representing the portion of the image p visible
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// through r. The returned value shares pixels with the original image.
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func (p *ycc) SubImage(r image.Rectangle) image.Image {
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r = r.Intersect(p.Rect)
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if r.Empty() {
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return &ycc{SubsampleRatio: p.SubsampleRatio}
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}
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i := p.PixOffset(r.Min.X, r.Min.Y)
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return &ycc{
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Pix: p.Pix[i:],
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Stride: p.Stride,
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Rect: r,
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SubsampleRatio: p.SubsampleRatio,
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}
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}
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// newYCC returns a new ycc with the given bounds and subsample ratio.
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func newYCC(r image.Rectangle, s image.YCbCrSubsampleRatio) *ycc {
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w, h := r.Dx(), r.Dy()
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buf := make([]uint8, 3*w*h)
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return &ycc{Pix: buf, Stride: 3 * w, Rect: r, SubsampleRatio: s}
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}
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// YCbCr converts ycc to a YCbCr image with the same subsample ratio
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// as the YCbCr image that ycc was generated from.
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func (p *ycc) YCbCr() *image.YCbCr {
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ycbcr := image.NewYCbCr(p.Rect, p.SubsampleRatio)
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var off int
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switch ycbcr.SubsampleRatio {
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case image.YCbCrSubsampleRatio422:
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for y := ycbcr.Rect.Min.Y; y < ycbcr.Rect.Max.Y; y++ {
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yy := (y - ycbcr.Rect.Min.Y) * ycbcr.YStride
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cy := (y - ycbcr.Rect.Min.Y) * ycbcr.CStride
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for x := ycbcr.Rect.Min.X; x < ycbcr.Rect.Max.X; x++ {
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xx := (x - ycbcr.Rect.Min.X)
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yi := yy + xx
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ci := cy + xx/2
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ycbcr.Y[yi] = p.Pix[off+0]
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ycbcr.Cb[ci] = p.Pix[off+1]
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ycbcr.Cr[ci] = p.Pix[off+2]
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off += 3
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}
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}
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case image.YCbCrSubsampleRatio420:
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for y := ycbcr.Rect.Min.Y; y < ycbcr.Rect.Max.Y; y++ {
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yy := (y - ycbcr.Rect.Min.Y) * ycbcr.YStride
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cy := (y/2 - ycbcr.Rect.Min.Y/2) * ycbcr.CStride
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for x := ycbcr.Rect.Min.X; x < ycbcr.Rect.Max.X; x++ {
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xx := (x - ycbcr.Rect.Min.X)
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yi := yy + xx
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ci := cy + xx/2
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ycbcr.Y[yi] = p.Pix[off+0]
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ycbcr.Cb[ci] = p.Pix[off+1]
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ycbcr.Cr[ci] = p.Pix[off+2]
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off += 3
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}
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}
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case image.YCbCrSubsampleRatio440:
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for y := ycbcr.Rect.Min.Y; y < ycbcr.Rect.Max.Y; y++ {
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yy := (y - ycbcr.Rect.Min.Y) * ycbcr.YStride
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cy := (y/2 - ycbcr.Rect.Min.Y/2) * ycbcr.CStride
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for x := ycbcr.Rect.Min.X; x < ycbcr.Rect.Max.X; x++ {
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xx := (x - ycbcr.Rect.Min.X)
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yi := yy + xx
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ci := cy + xx
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ycbcr.Y[yi] = p.Pix[off+0]
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ycbcr.Cb[ci] = p.Pix[off+1]
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ycbcr.Cr[ci] = p.Pix[off+2]
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off += 3
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}
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}
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default:
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// Default to 4:4:4 subsampling.
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for y := ycbcr.Rect.Min.Y; y < ycbcr.Rect.Max.Y; y++ {
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yy := (y - ycbcr.Rect.Min.Y) * ycbcr.YStride
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cy := (y - ycbcr.Rect.Min.Y) * ycbcr.CStride
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for x := ycbcr.Rect.Min.X; x < ycbcr.Rect.Max.X; x++ {
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xx := (x - ycbcr.Rect.Min.X)
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yi := yy + xx
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ci := cy + xx
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ycbcr.Y[yi] = p.Pix[off+0]
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ycbcr.Cb[ci] = p.Pix[off+1]
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ycbcr.Cr[ci] = p.Pix[off+2]
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off += 3
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}
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}
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}
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return ycbcr
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}
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// imageYCbCrToYCC converts a YCbCr image to a ycc image for resizing.
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func imageYCbCrToYCC(in *image.YCbCr) *ycc {
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w, h := in.Rect.Dx(), in.Rect.Dy()
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buf := make([]uint8, 3*w*h)
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p := ycc{Pix: buf, Stride: 3 * w, Rect: in.Rect, SubsampleRatio: in.SubsampleRatio}
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var off int
|
||||
|
||||
switch in.SubsampleRatio {
|
||||
case image.YCbCrSubsampleRatio422:
|
||||
for y := in.Rect.Min.Y; y < in.Rect.Max.Y; y++ {
|
||||
yy := (y - in.Rect.Min.Y) * in.YStride
|
||||
cy := (y - in.Rect.Min.Y) * in.CStride
|
||||
for x := in.Rect.Min.X; x < in.Rect.Max.X; x++ {
|
||||
xx := (x - in.Rect.Min.X)
|
||||
yi := yy + xx
|
||||
ci := cy + xx/2
|
||||
p.Pix[off+0] = in.Y[yi]
|
||||
p.Pix[off+1] = in.Cb[ci]
|
||||
p.Pix[off+2] = in.Cr[ci]
|
||||
off += 3
|
||||
}
|
||||
}
|
||||
case image.YCbCrSubsampleRatio420:
|
||||
for y := in.Rect.Min.Y; y < in.Rect.Max.Y; y++ {
|
||||
yy := (y - in.Rect.Min.Y) * in.YStride
|
||||
cy := (y/2 - in.Rect.Min.Y/2) * in.CStride
|
||||
for x := in.Rect.Min.X; x < in.Rect.Max.X; x++ {
|
||||
xx := (x - in.Rect.Min.X)
|
||||
yi := yy + xx
|
||||
ci := cy + xx/2
|
||||
p.Pix[off+0] = in.Y[yi]
|
||||
p.Pix[off+1] = in.Cb[ci]
|
||||
p.Pix[off+2] = in.Cr[ci]
|
||||
off += 3
|
||||
}
|
||||
}
|
||||
case image.YCbCrSubsampleRatio440:
|
||||
for y := in.Rect.Min.Y; y < in.Rect.Max.Y; y++ {
|
||||
yy := (y - in.Rect.Min.Y) * in.YStride
|
||||
cy := (y/2 - in.Rect.Min.Y/2) * in.CStride
|
||||
for x := in.Rect.Min.X; x < in.Rect.Max.X; x++ {
|
||||
xx := (x - in.Rect.Min.X)
|
||||
yi := yy + xx
|
||||
ci := cy + xx
|
||||
p.Pix[off+0] = in.Y[yi]
|
||||
p.Pix[off+1] = in.Cb[ci]
|
||||
p.Pix[off+2] = in.Cr[ci]
|
||||
off += 3
|
||||
}
|
||||
}
|
||||
default:
|
||||
// Default to 4:4:4 subsampling.
|
||||
for y := in.Rect.Min.Y; y < in.Rect.Max.Y; y++ {
|
||||
yy := (y - in.Rect.Min.Y) * in.YStride
|
||||
cy := (y - in.Rect.Min.Y) * in.CStride
|
||||
for x := in.Rect.Min.X; x < in.Rect.Max.X; x++ {
|
||||
xx := (x - in.Rect.Min.X)
|
||||
yi := yy + xx
|
||||
ci := cy + xx
|
||||
p.Pix[off+0] = in.Y[yi]
|
||||
p.Pix[off+1] = in.Cb[ci]
|
||||
p.Pix[off+2] = in.Cr[ci]
|
||||
off += 3
|
||||
}
|
||||
}
|
||||
}
|
||||
return &p
|
||||
}
|
||||
|
|
@ -0,0 +1,121 @@
|
|||
/*
|
||||
Copyright (c) 2014, Charlie Vieth <charlie.vieth@gmail.com>
|
||||
|
||||
Permission to use, copy, modify, and/or distribute this software for any purpose
|
||||
with or without fee is hereby granted, provided that the above copyright notice
|
||||
and this permission notice appear in all copies.
|
||||
|
||||
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
|
||||
REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
|
||||
FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
|
||||
INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
|
||||
OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
|
||||
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
|
||||
THIS SOFTWARE.
|
||||
*/
|
||||
|
||||
package resize
|
||||
|
||||
import (
|
||||
"image"
|
||||
"testing"
|
||||
)
|
||||
|
||||
type Image interface {
|
||||
image.Image
|
||||
SubImage(image.Rectangle) image.Image
|
||||
}
|
||||
|
||||
func TestImage(t *testing.T) {
|
||||
testImage := []Image{
|
||||
newYCC(image.Rect(0, 0, 10, 10), image.YCbCrSubsampleRatio420),
|
||||
newYCC(image.Rect(0, 0, 10, 10), image.YCbCrSubsampleRatio422),
|
||||
newYCC(image.Rect(0, 0, 10, 10), image.YCbCrSubsampleRatio440),
|
||||
newYCC(image.Rect(0, 0, 10, 10), image.YCbCrSubsampleRatio444),
|
||||
}
|
||||
for _, m := range testImage {
|
||||
if !image.Rect(0, 0, 10, 10).Eq(m.Bounds()) {
|
||||
t.Errorf("%T: want bounds %v, got %v",
|
||||
m, image.Rect(0, 0, 10, 10), m.Bounds())
|
||||
continue
|
||||
}
|
||||
m = m.SubImage(image.Rect(3, 2, 9, 8)).(Image)
|
||||
if !image.Rect(3, 2, 9, 8).Eq(m.Bounds()) {
|
||||
t.Errorf("%T: sub-image want bounds %v, got %v",
|
||||
m, image.Rect(3, 2, 9, 8), m.Bounds())
|
||||
continue
|
||||
}
|
||||
// Test that taking an empty sub-image starting at a corner does not panic.
|
||||
m.SubImage(image.Rect(0, 0, 0, 0))
|
||||
m.SubImage(image.Rect(10, 0, 10, 0))
|
||||
m.SubImage(image.Rect(0, 10, 0, 10))
|
||||
m.SubImage(image.Rect(10, 10, 10, 10))
|
||||
}
|
||||
}
|
||||
|
||||
func TestConvertYCbCr(t *testing.T) {
|
||||
testImage := []Image{
|
||||
image.NewYCbCr(image.Rect(0, 0, 50, 50), image.YCbCrSubsampleRatio420),
|
||||
image.NewYCbCr(image.Rect(0, 0, 50, 50), image.YCbCrSubsampleRatio422),
|
||||
image.NewYCbCr(image.Rect(0, 0, 50, 50), image.YCbCrSubsampleRatio440),
|
||||
image.NewYCbCr(image.Rect(0, 0, 50, 50), image.YCbCrSubsampleRatio444),
|
||||
}
|
||||
|
||||
for _, img := range testImage {
|
||||
m := img.(*image.YCbCr)
|
||||
for y := m.Rect.Min.Y; y < m.Rect.Max.Y; y++ {
|
||||
for x := m.Rect.Min.X; x < m.Rect.Max.X; x++ {
|
||||
yi := m.YOffset(x, y)
|
||||
ci := m.COffset(x, y)
|
||||
m.Y[yi] = uint8(16*y + x)
|
||||
m.Cb[ci] = uint8(y + 16*x)
|
||||
m.Cr[ci] = uint8(y + 16*x)
|
||||
}
|
||||
}
|
||||
|
||||
// test conversion from YCbCr to ycc
|
||||
yc := imageYCbCrToYCC(m)
|
||||
for y := m.Rect.Min.Y; y < m.Rect.Max.Y; y++ {
|
||||
for x := m.Rect.Min.X; x < m.Rect.Max.X; x++ {
|
||||
ystride := 3 * (m.Rect.Max.X - m.Rect.Min.X)
|
||||
xstride := 3
|
||||
yi := m.YOffset(x, y)
|
||||
ci := m.COffset(x, y)
|
||||
si := (y * ystride) + (x * xstride)
|
||||
if m.Y[yi] != yc.Pix[si] {
|
||||
t.Errorf("Err Y - found: %d expected: %d x: %d y: %d yi: %d si: %d",
|
||||
m.Y[yi], yc.Pix[si], x, y, yi, si)
|
||||
}
|
||||
if m.Cb[ci] != yc.Pix[si+1] {
|
||||
t.Errorf("Err Cb - found: %d expected: %d x: %d y: %d ci: %d si: %d",
|
||||
m.Cb[ci], yc.Pix[si+1], x, y, ci, si+1)
|
||||
}
|
||||
if m.Cr[ci] != yc.Pix[si+2] {
|
||||
t.Errorf("Err Cr - found: %d expected: %d x: %d y: %d ci: %d si: %d",
|
||||
m.Cr[ci], yc.Pix[si+2], x, y, ci, si+2)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// test conversion from ycc back to YCbCr
|
||||
ym := yc.YCbCr()
|
||||
for y := m.Rect.Min.Y; y < m.Rect.Max.Y; y++ {
|
||||
for x := m.Rect.Min.X; x < m.Rect.Max.X; x++ {
|
||||
yi := m.YOffset(x, y)
|
||||
ci := m.COffset(x, y)
|
||||
if m.Y[yi] != ym.Y[yi] {
|
||||
t.Errorf("Err Y - found: %d expected: %d x: %d y: %d yi: %d",
|
||||
m.Y[yi], ym.Y[yi], x, y, yi)
|
||||
}
|
||||
if m.Cb[ci] != ym.Cb[ci] {
|
||||
t.Errorf("Err Cb - found: %d expected: %d x: %d y: %d ci: %d",
|
||||
m.Cb[ci], ym.Cb[ci], x, y, ci)
|
||||
}
|
||||
if m.Cr[ci] != ym.Cr[ci] {
|
||||
t.Errorf("Err Cr - found: %d expected: %d x: %d y: %d ci: %d",
|
||||
m.Cr[ci], ym.Cr[ci], x, y, ci)
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue