genesis

go.mod

@@ -0,0 +1,3 @@
+module forge.sunglocto.net/sunglocto/xep0392
+
+go 1.25.1

main.go

@@ -0,0 +1,59 @@
+package xep0392
+
+import (
+    "crypto/sha1"
+    "encoding/binary"
+    "fmt"
+    "image"
+    "image/color"
+    "math"
+)
+
+// TODO: import "github.com/hsluv/go-hsluv"
+func HsluvToRGB(h, s, l float64) (r, g, b float64) {
+    return 0, 0, 0
+}
+
+func ColorFromString(id string) color.RGBA {
+    hue := hueFromString(id)
+    s := 100.0
+    l := 50.0
+    r, g, b := HsluvToRGB(hue, s, l)
+    return color.RGBA{
+        R: uint8(clamp01(r) * 255),
+        G: uint8(clamp01(g) * 255),
+        B: uint8(clamp01(b) * 255),
+        A: 255,
+    }
+}
+
+func ImageWithColor(id string, width, height int) *image.RGBA {
+    c := ColorFromString(id)
+    img := image.NewRGBA(image.Rect(0, 0, width, height))
+    for y := 0; y < height; y++ {
+        for x := 0; x < width; x++ {
+            img.SetRGBA(x, y, c)
+        }
+    }
+    return img
+}
+
+func hueFromString(s string) float64 {
+    h := sha1.Sum([]byte(s))
+    v := binary.LittleEndian.Uint16(h[18:20])
+    hue := float64(v) * 360.0 / 65536.0
+    if hue >= 360.0 {
+        hue = math.Mod(hue, 360.0)
+    }
+    return hue
+}
+
+func clamp01(f float64) float64 {
+    if f < 0 {
+        return 0
+    }
+    if f > 1 {
+        return 1
+    }
+    return f
+}