Move icon generation into dedicated files

icons/icons.go

@@ -0,0 +1,64 @@
+package icons
+
+import (
+	"crypto/md5"
+	"encoding/hex"
+	"image"
+	"image/color"
+	"image/draw"
+	"regexp"
+)
+
+type IconGenerator interface {
+	GenIcon(id string, size int, f func([16]byte) color.RGBA) *image.NRGBA
+}
+
+func HashBytes(id string) [16]byte {
+	hash := [16]byte{}
+	md5RegExp := regexp.MustCompile("[a-f0-9]{32}")
+	if !md5RegExp.Match([]byte(id)) {
+		hash = md5.Sum([]byte(id))
+	} else {
+		dec, _ := hex.DecodeString(id)
+		for idx, b := range dec {
+			hash[idx] = b
+		}
+	}
+	return hash
+}
+
+func mirrorData(data []bool, blocks int) []bool {
+	for x := 0; x < blocks; x++ {
+		min := x*blocks + 1
+		for y := 0; y < blocks; y++ {
+			a := ((blocks - x - 1) * blocks) + y
+			b := min + y - 1
+			if data[a] {
+				data[b] = true
+			}
+		}
+	}
+	return data
+}
+
+func drawImage(data []bool, blocks int, size int, c color.Color) *image.NRGBA {
+	img := image.NewNRGBA(image.Rect(0, 0, size, size))
+
+	draw.Draw(img, img.Bounds(), &image.Uniform{color.Gray{240}}, image.Point{0, 0}, draw.Src)
+
+	blockSize := size / (blocks + 1)
+	border := (size - (blocks * blockSize)) / 2
+
+	for x := border; x < blockSize*blocks+border; x++ {
+		bx := (x - border) / blockSize
+		for y := border; y < blockSize*blocks+border; y++ {
+			by := (y - border) / blockSize
+			idx := bx*blocks + by
+			if data[idx] && (bx < blocks || by < blocks) {
+				img.Set(x, y, c)
+			}
+		}
+	}
+
+	return img
+}