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blurhashfactors.go
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blurhashfactors.go
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package imagehash
import "image"
// factorsYCbCR uses *image.YCbCr to produce factors
func factorsYCbCR(img *image.YCbCr, factors []float64) {
var factor float64
var scale float64
var lr, lg, lb float64
height := img.Bounds().Max.Y
width := img.Bounds().Max.X
size := float64(width * height)
for y := 0; y < height; y++ {
for x := 0; x < width; x++ {
rt, gt, bt, _ := img.YCbCrAt(x, y).RGBA()
lr = channelToLinear[rt>>8]
lg = channelToLinear[gt>>8]
lb = channelToLinear[bt>>8]
for yc := 0; yc < yComponents; yc++ {
for xc := 0; xc < xComponents; xc++ {
if xc != 0 || yc != 0 {
scale = 2 / size
} else {
scale = 1 / size
}
factor = xvalues[x+width*xc] * yvalues[y+height*yc] * scale
factors[0+xc*3+yc*3*xComponents] += lr * factor
factors[1+xc*3+yc*3*xComponents] += lg * factor
factors[2+xc*3+yc*3*xComponents] += lb * factor
}
}
}
}
}
// factorsRGBA uses *image.RGBA to produce factors
func factorsRGBA(img *image.RGBA, factors []float64) {
var factor float64
var scale float64
var lr, lg, lb float64
height := img.Bounds().Max.Y
width := img.Bounds().Max.X
size := float64(width * height)
for y := 0; y < height; y++ {
for x := 0; x < width; x++ {
rt, gt, bt, _ := img.RGBAAt(x, y).RGBA()
lr = channelToLinear[rt>>8]
lg = channelToLinear[gt>>8]
lb = channelToLinear[bt>>8]
for yc := 0; yc < yComponents; yc++ {
for xc := 0; xc < xComponents; xc++ {
if xc != 0 || yc != 0 {
scale = 2 / size
} else {
scale = 1 / size
}
factor = xvalues[x+width*xc] * yvalues[y+height*yc] * scale
factors[0+xc*3+yc*3*xComponents] += lr * factor
factors[1+xc*3+yc*3*xComponents] += lg * factor
factors[2+xc*3+yc*3*xComponents] += lb * factor
}
}
}
}
}
// factorsDefault uses image.Image to produce factors
func factorsDefault(img image.Image, factors []float64) {
var factor float64
var scale float64
var lr, lg, lb float64
height := img.Bounds().Max.Y
width := img.Bounds().Max.X
size := float64(width * height)
for y := 0; y < height; y++ {
for x := 0; x < width; x++ {
rt, gt, bt, _ := img.At(x, y).RGBA()
lr = channelToLinear[rt>>8]
lg = channelToLinear[gt>>8]
lb = channelToLinear[bt>>8]
for yc := 0; yc < yComponents; yc++ {
for xc := 0; xc < xComponents; xc++ {
if xc != 0 || yc != 0 {
scale = 2 / size
} else {
scale = 1 / size
}
factor = xvalues[x+width*xc] * yvalues[y+height*yc] * scale
factors[0+xc*3+yc*3*xComponents] += lr * factor
factors[1+xc*3+yc*3*xComponents] += lg * factor
factors[2+xc*3+yc*3*xComponents] += lb * factor
}
}
}
}
}