README banner: the logo above the STEWARD wordmark

scripts/banner.py builds artwork/banner.svg from the web UI's logo and
wordmark, as Jarl's does; scripts/logo.py runs it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/banner.py

@@ -0,0 +1,75 @@
+#!/usr/bin/env python3
+# Builds artwork/banner.svg, the README's banner: the logo above the
+# "STEWARD" wordmark and its DHCP rule, laid out as on the web UI's login
+# page. It reads both from the web UI's own sources, so it matches the login
+# page:
+#
+#   internal/web/static/assets/logo.js   the logo's shapes (from scripts/logo.py)
+#   internal/web/static/assets/brand.js  the wordmark's letters and width
+#
+# The rule is drawn here with the same numbers as wordmark() in brand.js;
+# keep the two in step. The letters and rule take the UI's text and accent
+# colors, switching to the dark theme's when the viewer prefers dark. Needs
+# only Python; run from the repository root after changing either file
+# (scripts/logo.py runs it):
+#
+#   python3 scripts/banner.py
+import json
+import re
+import sys
+
+ASSETS = "internal/web/static/assets"
+OUT = "artwork/banner.svg"
+
+# The UI's --text and --accent (style.css), light and dark.
+STYLE = (".t{fill:#1d2330}.a{fill:#2f5fb3}.l{fill:none;stroke:#2f5fb3;stroke-width:2.6}"
+         ".g{fill:#2f5fb3;font:700 17px system-ui,sans-serif;letter-spacing:.5px}"
+         "@media (prefers-color-scheme:dark){.t{fill:#e3e7ee}.a,.g{fill:#6d9be8}.l{stroke:#6d9be8}}")
+
+
+def main():
+    logo = open(f"{ASSETS}/logo.js").read()
+    view_box = re.search(r'viewBox = "([^"]*)"', logo).group(1)
+    shapes = [json.loads(m) for m in re.findall(r"^  (\[.*\]),$", logo, re.M)]
+
+    brand = open(f"{ASSETS}/brand.js").read()
+    letters = re.findall(r'\{ x: (\d+), d: "([^"]*)" \}', brand)
+    w = int(re.search(r"^const W = (\d+);", brand, re.M).group(1))
+    if len(shapes) < 5 or len(letters) != 7:
+        sys.exit("banner.py: logo.js or brand.js no longer looks as expected; update the script")
+
+    # The login page's sizes in pixels (style.css): a 104px logo, 10px above
+    # a 290px wordmark whose viewBox is W+8 units wide.
+    mark_w, mark_h = w + 8, 162
+    unit = mark_w / 290
+    logo_size, gap = round(104 * unit, 1), round(10 * unit, 1)
+    height = logo_size + gap + mark_h
+
+    c = w / 2
+    rule = (f'<path class="a" d="M2 18 L{c - 60:g} 15.6 V20.4 Z M{w - 2} 18 L{c + 60:g} 15.6 V20.4 Z"/>'
+            f'<circle class="l" cx="{c - 52:g}" cy="18" r="4.6"/>'
+            f'<path class="l" d="M{c - 47.4:g} 18 H{c - 30:g} M{c + 30:g} 18 H{c + 47.4:g}"/>'
+            f'<circle class="l" cx="{c:g}" cy="18" r="30"/>'
+            f'<circle class="l" cx="{c + 52:g}" cy="18" r="4.6"/>'
+            f'<text class="g" x="{c:g}" y="24.5" text-anchor="middle">DHCP</text>')
+
+    def shape(tag, attrs):
+        return f"<{tag} " + " ".join(f'{k}="{v}"' for k, v in attrs.items()) + "/>"
+
+    svg = [f'<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 {mark_w} {height:g}" role="img" aria-label="Steward">',
+           f"<!-- Generated by scripts/banner.py from {ASSETS}/logo.js and brand.js. -->",
+           f"<title>Steward</title><style>{STYLE}</style>",
+           f'<svg x="{(mark_w - logo_size) / 2:g}" width="{logo_size:g}" height="{logo_size:g}" viewBox="{view_box}">'
+           + "".join(shape(t, a) for t, a in shapes) + "</svg>",
+           f'<svg y="{logo_size + gap:g}" width="{mark_w}" height="{mark_h}" viewBox="-4 -4 {mark_w} {mark_h}">'
+           '<g class="t" fill-rule="evenodd">'
+           + "".join(f'<path transform="translate({x} 0)" d="{d}"/>' for x, d in letters) + "</g>"
+           f'<g transform="translate(0 118)">{rule}</g></svg>',
+           "</svg>"]
+    with open(OUT, "w") as f:
+        f.write("\n".join(svg) + "\n")
+    print(f"{OUT}: {mark_w}x{height:g}")
+
+
+if __name__ == "__main__":
+    sys.exit(main())

scripts/logo.py

@@ -8,13 +8,15 @@
 #                                        logo appears together with the page
 #
 # The master is hand-written SVG: <g> elements whose attributes apply to
-# their <path> and <circle> children. Run from the repository root after
-# changing it:
+# their <path> and <circle> children. It then runs scripts/banner.py to
+# rebuild the README's banner. Run from the repository root after changing
+# it:
 #
 #   python3 scripts/logo.py
 import json
 import os
 import shutil
+import subprocess
 import sys
 import xml.etree.ElementTree as ET
 
@@ -51,6 +53,7 @@ def main():
     shutil.copyfile(MASTER, os.path.join(OUT, "logo.svg"))
     for name in ("logo.svg", "logo.js"):
         print(f"{OUT}/{name}: {os.path.getsize(os.path.join(OUT, name))} bytes")
+    subprocess.run([sys.executable, "scripts/banner.py"], check=True)
 
 
 if __name__ == "__main__":