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package main
import (
"bytes"
"crypto/sha256"
"encoding/base64"
"flag"
"fmt"
"image"
"image/color"
"image/png"
"regexp"
"strings"
)
var usernamePattern = regexp.MustCompile("[a-zA-Z][a-zA-Z0-9]+")
func main() {
username := flag.String("username", "", "username to encode as image (must contain only letters a-zA-Z0-9 and start with a letter)")
flag.Parse()
if strings.TrimSpace(*username) == "" {
flag.Usage()
return
}
if !usernamePattern.MatchString(*username) {
flag.Usage()
return
}
seed := hash(*username)
img := repeat(generateImage(seed))
str, err := encodeImage(img)
if err != nil {
fmt.Printf("%v\n", err)
return
}
fmt.Println(str)
}
func hash(username string) [32]byte {
return sha256.Sum256([]byte(username))
}
func generateImage(hash [32]byte) image.Image {
img := image.NewNRGBA(image.Rect(0, 0, 5, 5))
colorA := color.NRGBA{
R: hash[0],
G: hash[1],
B: hash[2],
A: 255,
}
colorB := color.NRGBA{
R: hash[3],
G: hash[4],
B: hash[5],
A: 255,
}
offset := 6
for x := 0; x < 5; x++ {
for y := 0; y < 5; y++ {
on := hash[offset] > 127
color := colorA
if on {
color = colorB
}
img.Set(x, y, color)
offset++
}
}
return img
}
func encodeImage(img image.Image) (string, error) {
var b bytes.Buffer
if err := png.Encode(&b, img); err != nil {
return "", err
}
return base64.StdEncoding.EncodeToString(b.Bytes()), nil
}
func repeat(img image.Image) image.Image {
newImg := image.NewNRGBA(image.Rect(0, 0, 10, 10))
for x := 0; x < 5; x++ {
for y := 0; y < 5; y++ {
newImg.Set(x, y, img.At(x, y))
newImg.Set(9-x, y, img.At(x, y))
newImg.Set(x, 9-y, img.At(x, y))
newImg.Set(9-x, 9-y, img.At(x, y))
}
}
return newImg
}
// func makeBigger(img image.Image) image.Image {
// newImg := image.NewNRGBA(image.Rect(0, 0, 200, 200))
// for x := 0; x < 10; x++ {
// for y := 0; y < 10; y++ {
// }
// }
// }
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