feat: github implementation working; cleanup needed

main.go

@@ -1,8 +1,10 @@
 package main
 
 import (
+	"crypto/md5"
 	"crypto/sha1"
 	"fmt"
+	"math"
 	"slices"
 	"strconv"
 
@@ -12,11 +14,170 @@ import (
 func main() {
 	dc := gg.NewContext(800, 800)
 
-	XBitPolygons(dc, "Jaybee18", 8, 8)
+	GitHub(dc, "64578396")
+	// XBitPolygons(dc, "BigBor14", 6, 6)
+	// FourBitSquares(dc, "Jaybee18")
 
 	dc.SavePNG("out.png")
 }
 
+// Bit font character overlay mit xor
+
+func hue_to_rgb(a float32, b float32, hue float32) float32 {
+	var h float32
+	if hue < 0.0 {
+		h = hue + 1.0
+	} else if hue > 1.0 {
+		h = hue - 1.0
+	} else {
+		h = hue
+	}
+
+	if h < 1.0 / 6.0 {
+		return a + (b - a) * 6.0 * h
+	}
+
+	if h < 1.0 / 2.0 {
+		return b
+	}
+
+	if h < 2.0 / 3.0 {
+		return a + (b - a) * (2.0 / 3.0 - h) * 6.0
+	}
+
+	return a
+}
+
+func foreground(source []uint8) (int, int, int) {
+	h1 := (uint16(source[12]) & 0x0f) << 8;
+	h2 := uint16(source[13])
+
+	h := uint32(h1 | h2)
+	s := uint32(source[14])
+	l := uint32(source[15])
+
+	hue := float32(h * 360) / float32(4095)
+	sat := float32(s * 20) / float32(255)
+	lum := float32(l * 20) / float32(255)
+
+	sat = 65.0 - sat
+	lum = 75.0 - lum
+
+	hue = hue / 360.0
+	sat = sat / 100.0
+	lum = lum / 100.0
+
+	var b float32
+	if lum <= 0.5 {
+		b = lum * (sat + 1.0)
+	} else {
+		b = lum + sat - lum * sat
+	}
+	a := lum * 2.0 - b
+
+	r := hue_to_rgb(a, b, hue + 1.0 / 3.0)
+	g := hue_to_rgb(a, b, hue)
+	b = hue_to_rgb(a, b, hue - 1.0 / 3.0)
+
+	return int(math.Round(float64(r * 255))), int(math.Round(float64(g * 255))), int(math.Round(float64(b * 255)))
+}
+
+// Translated to Go from: https://github.com/dgraham/identicon
+func GitHub(dc *gg.Context, userId string) {
+	fmt.Printf("md5.Sum([]byte(userId)): %v\n", md5.Sum([]byte(userId)))
+	hash := md5.Sum([]byte(userId))
+	// userIdHash := "da02efbbbe97337447671769e0f50c4a" // ohne newline (richtiges symbol)
+	w := 800
+	h := 800
+	cols := 5
+	rows := 5
+	pw := w / cols
+	ph := h / rows
+
+	// Background
+	dc.SetRGB255(240, 240, 240)
+	dc.DrawRectangle(0, 0, float64(w), float64(h))
+	dc.Fill()
+
+	// Convert to bytes
+	// bytes := []uint8{}
+	// for i := 0; i < 32; i+=2 {
+	// 	integer, _ := strconv.ParseUint(string(userIdHash[i]) + string(userIdHash[i+1]), 16, 8)
+	// 	bytes = append(bytes, uint8(integer))
+	// }
+	// fmt.Println(bytes)
+
+	dc.SetRGB255(foreground(hash[:]))
+
+	// Foreground
+	enabledVertices := make([]bool, 25)
+	// for i, character := range userIdHash[:15] {
+	// 	integer, _ := strconv.ParseUint(string(character), 16, 8)
+	// 	fmt.Println(integer)
+	// 	painted := integer % 2 == 0
+
+	// 	rowIdx := i % 5
+	// 	colIdx := 2 - i / 5
+	// 	mirrColIdx := 2 + i / 5
+
+	// 	enabledVertices[rowIdx * 5 + colIdx] = painted
+	// 	enabledVertices[rowIdx * 5 + mirrColIdx] = painted
+	// }
+
+	for i := range 15 {
+		// integer, _ := strconv.ParseUint(string(character), 16, 8)
+		byte := hash[i/2]
+		var nibble uint8 // 4 bits are called a nibble
+		if i % 2 == 0 {
+			nibble = (byte & 0xf0) >> 4 // left side
+		} else {
+			nibble = byte & 0x0f // right side
+		}
+		painted := nibble % 2 == 0
+
+		rowIdx := i % 5
+		colIdx := 2 - i / 5
+		mirrColIdx := 2 + i / 5
+
+		enabledVertices[rowIdx * 5 + colIdx] = painted
+		enabledVertices[rowIdx * 5 + mirrColIdx] = painted
+	}
+
+
+	// 216 166 130
+	// Foreground color
+	// da02efbbbe97337447671769e0f50c4a
+	// h1 = 3 -> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 -> 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0
+	// h2 = 3 -> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1
+	// h = 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 1 1 = 771
+	// s = 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 = 7
+	// l = 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 = 4
+	// hue = 277560 / 4095 = 67,78021978 (73710)
+	// sat = 140 / 255 = 0,54901961
+	// lum = 80 / 255 = 0,31372549
+	//
+	// 67.78021978, 64.45098039, 74.68627451
+	// ---
+	//
+	// l = 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1 0 1 1 0 1 1 1 0 0 0 1 = 23409
+	// hue = 73710 / 4095 = 21.538462
+	// sat = 3213 / 255 = 12.6
+	// lum = 1836 / 255 = 7.2
+	// Solution: 18, 64.3, 69.2
+
+	for row, pix := range slices.Collect(slices.Chunk(enabledVertices, 5)) {
+		for col, painted := range pix {
+			if painted {
+				x := col * pw
+				y := row * ph
+
+				dc.DrawRectangle(float64(x), float64(y), float64(pw), float64(ph))
+				dc.Fill()
+			}
+		}
+	}
+}
+
 func XBitPolygons(dc *gg.Context, username string, columns int, rows int) {
 	hash := hash(username)
 
@@ -208,3 +369,11 @@ func hasBit(n uint64, pos int) bool {
     val := n & (1 << pos)
     return (val > 0)
 }
+
+func Map[T any, M any](a []T, f func(T) M) []M {
+    n := make([]M, len(a))
+    for i, e := range a {
+        n[i] = f(e)
+    }
+    return n
+}