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Comparator rework and fixes

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nxshock 2017-06-25 16:52:58 +05:00
parent ab1c13e694
commit eff44ff1cc
5 changed files with 117 additions and 16 deletions
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43
comparators.go
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@ -6,27 +6,48 @@ import (
)
// comparator is a function that returns a difference between two colors in
// range 0.0..1.0.
// range 0.0..1.0 (0.0 - same colors, 1.0 - totally different colors).
type comparator func(color.Color, color.Color) float64
// CmpSquareRGBComponentsDiff returns difference of two colors
func CmpSquareRGBComponentsDiff(color1 color.Color, color2 color.Color) float64 {
// CmpEuclidean returns Euclidean difference of two colors.
// https://en.wikipedia.org/wiki/Color_difference#Euclidean
func CmpEuclidean(color1 color.Color, color2 color.Color) float64 {
const maxDiff = 113509.94967402637 // Difference between black and white colors
r1, g1, b1, _ := color1.RGBA()
r2, g2, b2, _ := color2.RGBA()
return math.Sqrt(math.Pow(float64(r2)-float64(r1), 2.0)+
math.Pow(float64(g2)-float64(g1), 2.0)+
math.Pow(float64(b2)-float64(b1), 2.0)) / maxDiff
return math.Sqrt(distance(float64(r2), float64(r1))+
distance(float64(g2), float64(g1))+
distance(float64(b2), float64(b1))) / maxDiff
}
// CmpRGBComponentsDiff returns difference of two colors.
func CmpRGBComponentsDiff(color1 color.Color, color2 color.Color) float64 {
const maxDiff = 765 // Difference between black and white colors
// CmpRGBComponents returns RGB components difference of two colors.
func CmpRGBComponents(color1 color.Color, color2 color.Color) float64 {
const maxDiff = 195075.0 // Difference between black and white colors
r1, g1, b1, _ := color1.RGBA()
r2, g2, b2, _ := color2.RGBA()
return math.Sqrt(math.Abs(float64(r2)-float64(r1))+
math.Abs(float64(g2)-float64(g1))+
return (math.Abs(float64(r2)-float64(r1)) +
math.Abs(float64(g2)-float64(g1)) +
math.Abs(float64(b2)-float64(b1))) / maxDiff
}
// CmpCIE76 returns difference of two colors defined in CIE76 standart.
// https://en.wikipedia.org/wiki/Color_difference#CIE76
func CmpCIE76(color1 color.Color, color2 color.Color) float64 {
const maxDiff = 150.8463301377893 // Difference between blue and white colors
r1, g1, b1, _ := color1.RGBA()
r2, g2, b2, _ := color2.RGBA()
cl1, ca1, cb1 := xyztoLAB(rgbtoXYZ(r1/255, g1/255, b1/255))
cl2, ca2, cb2 := xyztoLAB(rgbtoXYZ(r2/255, g2/255, b2/255))
return math.Sqrt(distance(cl2, cl1) + distance(ca2, ca1) + distance(cb2, cb1))
}
func distance(x, y float64) float64 {
return (x - y) * (x - y)
}