From 7c80f5ce7e44b95d16e19de40de0f8079377c6b9 Mon Sep 17 00:00:00 2001
From: yyamashita <yyamashita@hetzner.yyamashita.com>
Date: Sat, 22 Aug 2026 19:21:12 +0900
Subject: Initial commit: todo app with passkey auth and PWA support

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 scripts/gen-icons.mjs | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 scripts/gen-icons.mjs

(limited to 'scripts')

diff --git a/scripts/gen-icons.mjs b/scripts/gen-icons.mjs
new file mode 100644
index 0000000..ea23326
--- /dev/null
+++ b/scripts/gen-icons.mjs
@@ -0,0 +1,98 @@
+import { deflateSync } from "zlib";
+import { writeFileSync, mkdirSync } from "fs";
+
+const CRC_TABLE = (() => {
+  const t = new Uint32Array(256);
+  for (let n = 0; n < 256; n++) {
+    let c = n;
+    for (let k = 0; k < 8; k++) c = c & 1 ? 0xedb88320 ^ (c >>> 1) : c >>> 1;
+    t[n] = c;
+  }
+  return t;
+})();
+
+function crc32(buf) {
+  let crc = 0xffffffff;
+  for (let i = 0; i < buf.length; i++) crc = CRC_TABLE[(crc ^ buf[i]) & 0xff] ^ (crc >>> 8);
+  return (crc ^ 0xffffffff) >>> 0;
+}
+
+function chunk(type, data) {
+  const typeBytes = Buffer.from(type, "ascii");
+  const crcVal = crc32(Buffer.concat([typeBytes, data]));
+  const out = Buffer.allocUnsafe(4 + 4 + data.length + 4);
+  out.writeUInt32BE(data.length, 0);
+  typeBytes.copy(out, 4);
+  data.copy(out, 8);
+  out.writeUInt32BE(crcVal, 8 + data.length);
+  return out;
+}
+
+// Purple #6c63ff = rgb(108, 99, 255)
+// With a white checkmark drawn on it
+function createIcon(size) {
+  const sig = Buffer.from([137, 80, 78, 71, 13, 10, 26, 10]);
+
+  const ihdr = Buffer.allocUnsafe(13);
+  ihdr.writeUInt32BE(size, 0);
+  ihdr.writeUInt32BE(size, 4);
+  ihdr[8] = 8; // bit depth
+  ihdr[9] = 2; // color type RGB
+  ihdr[10] = ihdr[11] = ihdr[12] = 0;
+
+  // Draw pixels: purple bg with white checkmark
+  const pixels = Buffer.alloc(size * size * 3);
+  const scale = size / 64;
+
+  // Fill purple
+  for (let i = 0; i < size * size; i++) {
+    pixels[i * 3] = 108;
+    pixels[i * 3 + 1] = 99;
+    pixels[i * 3 + 2] = 255;
+  }
+
+  // Draw white checkmark: ✓
+  // Checkmark path: (14,34)→(26,46)→(50,18) scaled to icon size
+  function setPixel(x, y) {
+    const xi = Math.round(x * scale);
+    const yi = Math.round(y * scale);
+    const thick = Math.max(2, Math.round(4 * scale));
+    for (let dy = -thick; dy <= thick; dy++) {
+      for (let dx = -thick; dx <= thick; dx++) {
+        const px = xi + dx;
+        const py = yi + dy;
+        if (px >= 0 && px < size && py >= 0 && py < size) {
+          pixels[(py * size + px) * 3] = 255;
+          pixels[(py * size + px) * 3 + 1] = 255;
+          pixels[(py * size + px) * 3 + 2] = 255;
+        }
+      }
+    }
+  }
+
+  // Left leg: (14,34) → (26,46)
+  const steps = 40;
+  for (let i = 0; i <= steps; i++) {
+    setPixel(14 + (26 - 14) * (i / steps), 34 + (46 - 34) * (i / steps));
+  }
+  // Right leg: (26,46) → (50,18)
+  for (let i = 0; i <= steps; i++) {
+    setPixel(26 + (50 - 26) * (i / steps), 46 + (18 - 46) * (i / steps));
+  }
+
+  // Build scanlines with filter=0 prefix
+  const raw = Buffer.allocUnsafe(size * (1 + size * 3));
+  for (let y = 0; y < size; y++) {
+    raw[y * (1 + size * 3)] = 0;
+    pixels.copy(raw, y * (1 + size * 3) + 1, y * size * 3, (y + 1) * size * 3);
+  }
+
+  const compressed = deflateSync(raw);
+
+  return Buffer.concat([sig, chunk("IHDR", ihdr), chunk("IDAT", compressed), chunk("IEND", Buffer.alloc(0))]);
+}
+
+mkdirSync("public/icons", { recursive: true });
+writeFileSync("public/icons/icon-192.png", createIcon(192));
+writeFileSync("public/icons/icon-512.png", createIcon(512));
+console.log("Icons generated: public/icons/icon-{192,512}.png");
-- 
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