1package main
 2
 3import (
 4	"bytes"
 5	"crypto/sha512"
 6	"image"
 7	"image/png"
 8)
 9
10func avatar(name string) []byte {
11	h := sha512.New()
12	h.Write([]byte(name))
13	s := h.Sum(nil)
14	img := image.NewNRGBA(image.Rect(0, 0, 64, 64))
15	for i := 0; i < 64; i++ {
16		for j := 0; j < 64; j++ {
17			p := i*img.Stride + j*4
18			xx := i/16*16 + j/16
19			x := s[xx]
20			if x < 64 {
21				img.Pix[p+0] = 32
22				img.Pix[p+1] = 0
23				img.Pix[p+2] = 64
24				img.Pix[p+3] = 255
25			} else if x < 128 {
26				img.Pix[p+0] = 32
27				img.Pix[p+1] = 0
28				img.Pix[p+2] = 92
29				img.Pix[p+3] = 255
30			} else if x < 192 {
31				img.Pix[p+0] = 64
32				img.Pix[p+1] = 0
33				img.Pix[p+2] = 128
34				img.Pix[p+3] = 255
35			} else {
36				img.Pix[p+0] = 96
37				img.Pix[p+1] = 0
38				img.Pix[p+2] = 160
39				img.Pix[p+3] = 255
40			}
41		}
42	}
43	var buf bytes.Buffer
44	png.Encode(&buf, img)
45	return buf.Bytes()
46}