Generate app icons from SVG at build time

data/icons/generate_icons.py

@@ -0,0 +1,121 @@
+#!/usr/bin/env python3
+import argparse
+import contextlib
+import pathlib
+import shutil
+import subprocess
+import tempfile
+
+SIZES = [16, 24, 32, 40, 48, 64, 96, 128, 256]
+
+
+def run(cmd):
+    subprocess.run(cmd, check=True)
+
+
+def try_run(cmd):
+    result = subprocess.run(cmd, text=True, capture_output=True)
+    return result.returncode == 0, result.stderr.strip()
+
+
+def magick_cmd():
+    magick = shutil.which('magick')
+    if not magick:
+        raise RuntimeError('missing tool: install ImageMagick (magick)')
+    return magick
+
+
+@contextlib.contextmanager
+def magick_svg(svg):
+    text = pathlib.Path(svg).read_text(encoding='utf-8')
+    fixed = text.replace('href="image/', 'href="data:image/')
+    fixed = fixed.replace('xlink:href="image/', 'xlink:href="data:image/')
+    if fixed == text:
+        yield str(svg)
+        return
+    with tempfile.NamedTemporaryFile('w', suffix='.svg', delete=False, encoding='utf-8') as tmp:
+        tmp.write(fixed)
+        tmp_path = tmp.name
+    try:
+        yield tmp_path
+    finally:
+        pathlib.Path(tmp_path).unlink(missing_ok=True)
+
+
+def render_png(svg, out_png, size):
+    errors = []
+    rsvg = shutil.which('rsvg-convert')
+    if rsvg:
+        ok, err = try_run([rsvg, '-w', str(size), '-h', str(size), '-o', str(out_png), str(svg)])
+        if ok:
+            return
+        errors.append(err)
+    inkscape = shutil.which('inkscape')
+    if inkscape:
+        ok, err = try_run([
+            inkscape,
+            str(svg),
+            '--export-type=png',
+            '--export-width',
+            str(size),
+            '--export-height',
+            str(size),
+            '--export-filename',
+            str(out_png),
+        ])
+        if ok:
+            return
+        errors.append(err)
+    with magick_svg(svg) as svg_for_magick:
+        ok, err = try_run([
+            magick_cmd(),
+            svg_for_magick,
+            '-background',
+            'none',
+            '-resize',
+            f'{size}x{size}',
+            str(out_png),
+        ])
+    if ok:
+        return
+    errors.append(err)
+    raise RuntimeError('failed to render png: ' + ' | '.join(e for e in errors if e))
+
+
+def build_ico(svg, out_ico):
+    with magick_svg(svg) as svg_for_magick:
+        run([
+            magick_cmd(),
+            svg_for_magick,
+            '-background',
+            'none',
+            '-define',
+            'icon:auto-resize=' + ','.join(str(size) for size in SIZES),
+            str(out_ico),
+        ])
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(prog='generate_icons.py')
+    parser.add_argument('input_svg')
+    parser.add_argument('output_png')
+    parser.add_argument('--ico', dest='output_ico')
+    parser.add_argument('--size', type=int, default=48)
+    return parser.parse_args()
+
+
+def main():
+    args = parse_args()
+    magick_cmd()
+    svg = pathlib.Path(args.input_svg)
+    out_png = pathlib.Path(args.output_png)
+    out_png.parent.mkdir(parents=True, exist_ok=True)
+    render_png(svg, out_png, args.size)
+    if args.output_ico:
+        out_ico = pathlib.Path(args.output_ico)
+        out_ico.parent.mkdir(parents=True, exist_ok=True)
+        build_ico(svg, out_ico)
+
+
+if __name__ == '__main__':
+    main()