61 lines
1.1 KiB
Go
61 lines
1.1 KiB
Go
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package identicon
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import (
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"crypto/md5"
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colorful "github.com/lucasb-eyer/go-colorful"
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"image/color"
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)
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const (
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defaultSaturation = 0.5
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defaultLightness = 0.7
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)
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type Identicon struct {
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bitmap []byte
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color color.Color
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}
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func generate(key string) Identicon {
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hash := md5.Sum([]byte(key))
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return Identicon{
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convertPatternToBinarySwitch(generatePatternFromHash(hash)),
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getColorFromHash(hash),
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}
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}
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func getColorFromHash(h [16]byte) color.Color {
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// Take the last 3 relevant bytes, and convert to a float between [0..360]
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var sum float64 = float64(h[13]) + float64(h[14]) + float64(h[15])
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t := (sum / 765) * 360
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return colorful.Hsl(t, defaultSaturation, defaultLightness)
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}
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func generatePatternFromHash(sum [16]byte) []byte {
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p := make([]byte, 25)
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for i := 0; i < 5; i++ {
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for j := 0; j < 5; j++ {
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jCount := j
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if j > 2 {
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jCount = 4 - j
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}
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p[5*i+j] = sum[3*i+jCount]
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}
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}
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return p
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}
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func convertPatternToBinarySwitch(pattern []byte) []byte {
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b := make([]byte, 25)
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for i, v := range pattern {
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if v%2 == 0 {
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b[i] = 1
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} else {
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b[i] = 0
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}
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}
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return b
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}
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