70 lines
1.3 KiB
Go
70 lines
1.3 KiB
Go
package utils
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import (
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"fmt"
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"math"
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)
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const (
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Pred float64 = 0.299
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Pgreen float64 = 0.587
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Pblue float64 = 0.114
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)
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func IsDarkColor(r, g, b uint8) bool {
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lum := Luminance(r, g, b)
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return lum <= 130
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}
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func IntToRgb(color uint32) (uint8, uint8, uint8) {
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b := color % 256
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g := color / 256 % 256
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r := color / (256 * 256) % 256
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return uint8(r), uint8(g), uint8(b)
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}
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func RgbToString(r, g, b uint8) string {
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return fmt.Sprintf("#%02x%02x%02x", r, g, b)
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}
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func AltColor(r, g, b uint8) (uint8, uint8, uint8) {
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brightnessAmount := -0.6
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if IsDarkColor(r, g, b) {
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brightnessAmount = 0.85
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}
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return Brighten(r, g, b, brightnessAmount)
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}
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func Brighten(r, g, b uint8, amount float64) (uint8, uint8, uint8) {
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return multiply(r, amount), multiply(g, amount), multiply(b, amount)
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}
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func multiply(i uint8, amount float64) uint8 {
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iF := float64(i)
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return uint8(
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math.Max(
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0,
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math.Min(
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255, iF+255*amount,
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),
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),
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)
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}
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func Luminance(r, g, b uint8) float64 {
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rC := Pred * math.Pow(float64(r), 2)
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gC := Pgreen * math.Pow(float64(g), 2)
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bC := Pblue * math.Pow(float64(b), 2)
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return math.Sqrt(rC + gC + bC)
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}
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func WCAGRatio(l1, l2 float64) float64 {
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if l1 < l2 {
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return (l1 + 0.05) / (l2 + 0.05)
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} else {
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return (l2 + 0.05) / (l1 + 0.05)
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}
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}
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