feat: Add icon generation script and update README with new functionality

build/scripts/generate_icons.py

@@ -0,0 +1,150 @@
+#!/usr/bin/env python3
+"""Generate application icons for Windows (.ico) and macOS (.icns).
+
+This script creates both platform icon formats from a single master PNG so
+branding stays visually consistent across installers.
+
+Requirements:
+- Pillow (for .ico generation)
+- macOS tools `sips` and `iconutil` (for .icns generation)
+"""
+
+from __future__ import annotations
+
+import argparse
+import shutil
+import subprocess
+import sys
+import tempfile
+from pathlib import Path
+
+ICONSET_ENTRIES: list[tuple[str, int]] = [
+    ("icon_16x16.png", 16),
+    ("icon_16x16@2x.png", 32),
+    ("icon_32x32.png", 32),
+    ("icon_32x32@2x.png", 64),
+    ("icon_128x128.png", 128),
+    ("icon_128x128@2x.png", 256),
+    ("icon_256x256.png", 256),
+    ("icon_256x256@2x.png", 512),
+    ("icon_512x512.png", 512),
+    ("icon_512x512@2x.png", 1024),
+]
+
+ICO_SIZES = [(16, 16), (24, 24), (32, 32), (48, 48), (64, 64), (128, 128), (256, 256)]
+
+
+def _run(cmd: list[str]) -> None:
+    subprocess.run(cmd, check=True)
+
+
+def _require_tool(name: str) -> None:
+    if shutil.which(name):
+        return
+    raise RuntimeError(
+        f"Required tool '{name}' not found in PATH. "
+        f"Install it and retry."
+    )
+
+
+def generate_icns(source_png: Path, target_icns: Path) -> None:
+    """Generate macOS .icns using iconutil and sips."""
+    _require_tool("sips")
+    _require_tool("iconutil")
+
+    target_icns.parent.mkdir(parents=True, exist_ok=True)
+
+    with tempfile.TemporaryDirectory(prefix="webdrop_iconset_") as tmp:
+        iconset_dir = Path(tmp) / "app.iconset"
+        iconset_dir.mkdir(parents=True, exist_ok=True)
+
+        for filename, size in ICONSET_ENTRIES:
+            out_file = iconset_dir / filename
+            _run(
+                [
+                    "sips",
+                    "-z",
+                    str(size),
+                    str(size),
+                    str(source_png),
+                    "--out",
+                    str(out_file),
+                ]
+            )
+
+        _run(["iconutil", "-c", "icns", str(iconset_dir), "-o", str(target_icns)])
+
+
+def generate_ico(source_png: Path, target_ico: Path) -> None:
+    """Generate Windows .ico using Pillow."""
+    try:
+        from PIL import Image
+    except ImportError as exc:
+        raise RuntimeError(
+            "Pillow is required for .ico generation. "
+            "Install it with: pip install Pillow"
+        ) from exc
+
+    target_ico.parent.mkdir(parents=True, exist_ok=True)
+
+    with Image.open(source_png) as img:
+        rgba = img.convert("RGBA")
+        rgba.save(target_ico, format="ICO", sizes=ICO_SIZES)
+
+
+def parse_args() -> argparse.Namespace:
+    parser = argparse.ArgumentParser(
+        description="Generate .ico and .icns icons from a single PNG source"
+    )
+    parser.add_argument(
+        "--source",
+        default="resources/icons/app.png",
+        help="Master source PNG (default: resources/icons/app.png)",
+    )
+    parser.add_argument(
+        "--icon-ico",
+        default="resources/icons/app.ico",
+        help="Target .ico path (default: resources/icons/app.ico)",
+    )
+    parser.add_argument(
+        "--icon-icns",
+        default="resources/icons/app.icns",
+        help="Target .icns path (default: resources/icons/app.icns)",
+    )
+    parser.add_argument(
+        "--only",
+        choices=["all", "ico", "icns"],
+        default="all",
+        help="Generate all icons or only one format",
+    )
+    return parser.parse_args()
+
+
+def main() -> int:
+    args = parse_args()
+
+    source = Path(args.source).resolve()
+    icon_ico = Path(args.icon_ico).resolve()
+    icon_icns = Path(args.icon_icns).resolve()
+
+    if not source.exists():
+        print(f"ERROR: Source icon not found: {source}")
+        return 1
+
+    try:
+        if args.only in {"all", "ico"}:
+            generate_ico(source, icon_ico)
+            print(f"OK: Generated ICO: {icon_ico}")
+
+        if args.only in {"all", "icns"}:
+            generate_icns(source, icon_icns)
+            print(f"OK: Generated ICNS: {icon_icns}")
+
+        return 0
+    except (subprocess.CalledProcessError, RuntimeError) as exc:
+        print(f"ERROR: {exc}")
+        return 1
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())