зеркало из https://github.com/mislav/hub.git
141 строка
2.8 KiB
Go
141 строка
2.8 KiB
Go
package utils
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import (
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"fmt"
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"math"
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"os"
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"strconv"
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)
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var (
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Black *Color
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White *Color
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)
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func init() {
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initColorCube()
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Black, _ = NewColor("000000")
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White, _ = NewColor("ffffff")
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}
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type Color struct {
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Red uint8
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Green uint8
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Blue uint8
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}
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func NewColor(hex string) (*Color, error) {
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red, err := strconv.ParseUint(hex[0:2], 16, 8)
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if err != nil {
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return nil, err
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}
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green, err := strconv.ParseUint(hex[2:4], 16, 8)
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if err != nil {
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return nil, err
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}
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blue, err := strconv.ParseUint(hex[4:6], 16, 8)
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if err != nil {
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return nil, err
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}
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return &Color{
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Red: uint8(red),
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Green: uint8(green),
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Blue: uint8(blue),
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}, nil
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}
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func (c *Color) Distance(other *Color) float64 {
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return math.Sqrt(math.Pow(float64(c.Red-other.Red), 2) +
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math.Pow(float64(c.Green-other.Green), 2) +
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math.Pow(float64(c.Blue-other.Blue), 2))
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}
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func rgbComponentToBoldValue(component uint8) float64 {
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srgb := float64(component) / 255
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if srgb <= 0.03928 {
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return srgb / 12.92
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}
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return math.Pow(((srgb + 0.055) / 1.055), 2.4)
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}
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func (c *Color) Luminance() float64 {
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return 0.2126*rgbComponentToBoldValue(c.Red) +
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0.7152*rgbComponentToBoldValue(c.Green) +
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0.0722*rgbComponentToBoldValue(c.Blue)
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}
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func (c *Color) ContrastRatio(other *Color) float64 {
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L := c.Luminance()
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otherL := other.Luminance()
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var L1, L2 float64
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if L > otherL {
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L1, L2 = L, otherL
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} else {
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L1, L2 = otherL, L
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}
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ratio := (L1 + 0.05) / (L2 + 0.05)
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return ratio
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}
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var x6colorIndexes = [6]uint8{0, 95, 135, 175, 215, 255}
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var x6colorCube [216]Color
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func initColorCube() {
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i := 0
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for iR := 0; iR < 6; iR++ {
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for iG := 0; iG < 6; iG++ {
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for iB := 0; iB < 6; iB++ {
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x6colorCube[i] = Color{
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x6colorIndexes[iR],
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x6colorIndexes[iG],
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x6colorIndexes[iB],
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}
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i++
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}
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}
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}
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}
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func ditherTo256ColorCode(color *Color) (code int) {
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iMatch := -1
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minDistance := float64(99999)
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for i := 0; i < 216; i++ {
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distance := color.Distance(&x6colorCube[i])
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if distance < minDistance {
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iMatch = i
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minDistance = distance
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}
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}
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return iMatch + 16
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}
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var non24bitColorTerms = []string{
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"Apple_Terminal",
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}
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var isTerm24bitColorCapableCache bool
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var isTerm24bitColorCapableCacheIsInit bool = false
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func isTerm24bitColorCapable() bool {
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if !isTerm24bitColorCapableCacheIsInit {
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isTerm24bitColorCapableCache = true
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myTermProg := os.Getenv("TERM_PROGRAM")
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for _, brokenTerm := range non24bitColorTerms {
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if myTermProg == brokenTerm {
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isTerm24bitColorCapableCache = false
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break
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}
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}
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isTerm24bitColorCapableCacheIsInit = true
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}
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return isTerm24bitColorCapableCache
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}
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func RgbToTermColorCode(color *Color) string {
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if isTerm24bitColorCapable() {
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return fmt.Sprintf("2;%d;%d;%d", color.Red, color.Green, color.Blue)
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}
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intCode := ditherTo256ColorCode(color)
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return fmt.Sprintf("5;%d", intCode)
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}
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