chore: add documentation logos

logos/README.md

@@ -16,6 +16,31 @@ This directory contains the Anemoi logo in three variants:
   <img src="logo-text-right.svg" alt="Logo with text on the right" height="160">
 </p>
 
+## Documentation logos (Read the Docs)
+
+To produce a logo with a custom sub-title under the "anemoi" wordmark — for
+example one per documentation site on Read the Docs — use `make_logo.py`. It
+reads [`docs-logo-template.svg`](docs-logo-template.svg), substitutes your
+string, and centres it automatically (glyph widths are embedded in the script,
+so it has no dependencies and needs no network or font files).
+
+Create the SVG:
+
+```bash
+python3 make_logo.py metadata        # writes metadata.svg
+```
+
+Then rasterise it to a 640-pixel-wide PNG (see
+[Creating PNGs from the SVGs](#creating-pngs-from-the-svgs) for installing a
+converter):
+
+```bash
+rsvg-convert -w 640 metadata.svg -o metadata.png
+```
+
+Pass `-o` to choose a different SVG filename, e.g.
+`python3 make_logo.py "inference" -o logo-inference.svg`.
+
 ## About SVG
 
 The logos are provided as **SVG** (Scalable Vector Graphics). SVG is a vector

logos/make_logo.py

@@ -0,0 +1,188 @@
+#!/usr/bin/env python3
+# (C) Copyright 2026 Anemoi contributors.
+#
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation
+# nor does it submit to any jurisdiction.
+
+"""Render a logo SVG from docs-logo-template.svg with a custom sub-title string.
+
+Reads ``docs-logo-template.svg``, replaces the ``template`` text with the given
+string, and horizontally centres it using the glyph-width table embedded below.
+
+The centre line is taken from the "anemoi" text element in the template, so the
+sub-title always sits centred under the logo word — even if the template moves.
+
+Usage:
+    ./make_logo.py metadata                  # -> metadata.svg
+    ./make_logo.py "inference" -o foo.svg
+"""
+
+import argparse
+import re
+import sys
+
+TEMPLATE = "docs-logo-template.svg"
+
+# Advance widths in em units (fraction of font size), keyed by codepoint.
+
+_WIDTHS = {
+    32: 0.296,
+    33: 0.444,
+    34: 0.52,
+    35: 0.592,
+    36: 0.592,
+    37: 0.907,
+    38: 0.759,
+    39: 0.296,
+    40: 0.314,
+    41: 0.314,
+    42: 0.482,
+    43: 0.666,
+    44: 0.296,
+    45: 0.296,
+    46: 0.296,
+    47: 0.407,
+    48: 0.592,
+    49: 0.592,
+    50: 0.592,
+    51: 0.592,
+    52: 0.592,
+    53: 0.592,
+    54: 0.592,
+    55: 0.592,
+    56: 0.592,
+    57: 0.592,
+    58: 0.296,
+    59: 0.296,
+    60: 0.666,
+    61: 0.666,
+    62: 0.666,
+    63: 0.556,
+    64: 0.8,
+    65: 0.741,
+    66: 0.648,
+    67: 0.685,
+    68: 0.759,
+    69: 0.63,
+    70: 0.593,
+    71: 0.778,
+    72: 0.759,
+    73: 0.296,
+    74: 0.5,
+    75: 0.722,
+    76: 0.537,
+    77: 0.944,
+    78: 0.815,
+    79: 0.832,
+    80: 0.63,
+    81: 0.852,
+    82: 0.648,
+    83: 0.574,
+    84: 0.574,
+    85: 0.741,
+    86: 0.704,
+    87: 1.0,
+    88: 0.722,
+    89: 0.648,
+    90: 0.63,
+    91: 0.296,
+    92: 0.407,
+    93: 0.296,
+    94: 0.666,
+    95: 0.5,
+    96: 0.26,
+    97: 0.537,
+    98: 0.63,
+    99: 0.482,
+    100: 0.63,
+    101: 0.574,
+    102: 0.37,
+    103: 0.63,
+    104: 0.574,
+    105: 0.26,
+    106: 0.26,
+    107: 0.556,
+    108: 0.26,
+    109: 0.87,
+    110: 0.574,
+    111: 0.61,
+    112: 0.63,
+    113: 0.63,
+    114: 0.407,
+    115: 0.463,
+    116: 0.407,
+    117: 0.574,
+    118: 0.556,
+    119: 0.833,
+    120: 0.556,
+    121: 0.556,
+    122: 0.5,
+    123: 0.37,
+    124: 0.222,
+    125: 0.37,
+    126: 0.666,
+}
+
+
+def text_width(string, size):
+    missing = [c for c in string if ord(c) not in _WIDTHS]
+    if missing:
+        sys.exit(f"error: no width for {missing!r}; only printable ASCII is supported")
+    return sum(_WIDTHS[ord(c)] for c in string) * size
+
+
+def attr(tag, name):
+    m = re.search(rf'{name}="([^"]*)"', tag)
+    if not m:
+        sys.exit(f"error: attribute {name!r} not found in: {tag}")
+    return m.group(1)
+
+
+def find_text(svg, ident):
+    """Return the full <text id="ident" ...>content</text> element."""
+    m = re.search(rf'<text id="{ident}"[^>]*>.*?</text>', svg)
+    if not m:
+        sys.exit(f'error: no <text id="{ident}"> in template')
+    return m.group(0)
+
+
+def main(argv=None):
+    p = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
+    p.add_argument("text", help="sub-title string to render")
+    p.add_argument("-o", "--output", help="output SVG (default: <text>.svg)")
+    p.add_argument("--white", action="store_true", help="render sub-title text in white (for dark mode)")
+    p.add_argument("--template", default=TEMPLATE)
+    args = p.parse_args(argv)
+
+    svg = open(args.template, encoding="utf-8").read()
+
+    # Centre line = centre of the "anemoi" logo word.
+    anemoi = find_text(svg, "anemoi")
+    a_x = float(attr(anemoi, "x"))
+    a_size = float(attr(anemoi, "font-size"))
+    a_content = re.search(r">([^<]*)</text>", anemoi).group(1)
+    centre = a_x + text_width(a_content, a_size) / 2
+
+    # Replace the template sub-title, re-centred on `centre`.
+    tmpl = find_text(svg, "template")
+    t_size = float(attr(tmpl, "font-size"))
+    new_x = centre - text_width(args.text, t_size) / 2
+
+    new_tag = re.sub(r'x="[^"]*"', f'x="{new_x:.4f}"', tmpl, count=1)
+    new_tag = re.sub(r">([^<]*)</text>", f">{args.text}</text>", new_tag, count=1)
+    if args.white:
+        new_tag = re.sub(r'fill="[^"]*"', 'fill="#ffffff"', new_tag, count=1)
+
+    out_svg = svg.replace(tmpl, new_tag, 1)
+    out_path = args.output or f"{args.text}.svg"
+    with open(out_path, "w", encoding="utf-8") as fh:
+        fh.write(out_svg)
+    print(f"wrote {out_path}: {args.text!r} centred on x={centre:.3f} (x={new_x:.4f})", file=sys.stderr)
+
+
+if __name__ == "__main__":
+    main()