honk/avatar.go

62 lines
1.6 KiB
Go

//
// Copyright (c) 2019 Ted Unangst <tedu@tedunangst.com>
//
// Permission to use, copy, modify, and distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
package main
import (
"bytes"
"crypto/sha512"
"image"
"image/png"
)
func avatar(name string) []byte {
h := sha512.New()
h.Write([]byte(name))
s := h.Sum(nil)
img := image.NewNRGBA(image.Rect(0, 0, 64, 64))
for i := 0; i < 64; i++ {
for j := 0; j < 64; j++ {
p := i*img.Stride + j*4
xx := i/16*16 + j/16
x := s[xx]
if x < 64 {
img.Pix[p+0] = 32
img.Pix[p+1] = 0
img.Pix[p+2] = 64
img.Pix[p+3] = 255
} else if x < 128 {
img.Pix[p+0] = 32
img.Pix[p+1] = 0
img.Pix[p+2] = 92
img.Pix[p+3] = 255
} else if x < 192 {
img.Pix[p+0] = 64
img.Pix[p+1] = 0
img.Pix[p+2] = 128
img.Pix[p+3] = 255
} else {
img.Pix[p+0] = 96
img.Pix[p+1] = 0
img.Pix[p+2] = 160
img.Pix[p+3] = 255
}
}
}
var buf bytes.Buffer
png.Encode(&buf, img)
return buf.Bytes()
}