From 42513af1a5e81dae05699fb4acdb79cad67a258c Mon Sep 17 00:00:00 2001
From: kevin9327 <kevin9327@users.noreply.github.com>
Date: Wed, 21 Oct 2026 20:30:35 +0900
Subject: [PATCH] Read the stage size from <svg id="stage"> and accept
 single-quoted viewBox

---
 skills/motion2code/scripts/_m2c.py        | 12 +++++--
 skills/motion2code/scripts/render_anim.py |  2 +-
 tests/test_stage_size.py                  | 44 +++++++++++++++++++++++
 3 files changed, 54 insertions(+), 4 deletions(-)
 create mode 100644 tests/test_stage_size.py

diff --git a/skills/motion2code/scripts/_m2c.py b/skills/motion2code/scripts/_m2c.py
index 64d638e..a33291c 100644
--- a/skills/motion2code/scripts/_m2c.py
+++ b/skills/motion2code/scripts/_m2c.py
@@ -126,10 +126,16 @@ def launch(p):
 
 
 def stage_size(html: str | Path) -> tuple[int, int]:
-    """Stage size from the first <svg viewBox> (falls back to 1920x1080)."""
+    """Stage size from the viewBox of <svg id="stage">, else the first <svg viewBox> (falls back to 1920x1080)."""
     txt = Path(html).read_text(encoding="utf-8", errors="ignore")
-    m = re.search(r'<svg[^>]*viewBox="\s*[-\d.]+[\s,]+[-\d.]+[\s,]+([\d.]+)[\s,]+([\d.]+)', txt)
-    return (int(float(m.group(1))), int(float(m.group(2)))) if m else (1920, 1080)
+    vb = r"""\bviewBox=["']\s*[-\d.]+[\s,]+[-\d.]+[\s,]+([\d.]+)[\s,]+([\d.]+)"""
+    svgs = re.findall(r"<svg\b[^>]*>", txt, flags=re.I)
+    stage = [t for t in svgs if re.search(r"""\bid=["']stage["']""", t)]
+    for tag in stage + svgs:
+        m = re.search(vb, tag)
+        if m:
+            return int(float(m.group(1))), int(float(m.group(2)))
+    return 1920, 1080
 
 
 def parse_size(s: str | None, html: str | Path) -> tuple[int, int]:
diff --git a/skills/motion2code/scripts/render_anim.py b/skills/motion2code/scripts/render_anim.py
index aac04d5..3c7e668 100644
--- a/skills/motion2code/scripts/render_anim.py
+++ b/skills/motion2code/scripts/render_anim.py
@@ -53,7 +53,7 @@ def main():
     ap.add_argument("--fps", type=float, default=24)
     ap.add_argument("--duration", type=float, help="seconds to render (default: window.anim.duration)")
     ap.add_argument("--start", type=float, default=0.0)
-    ap.add_argument("--size", help="viewport WxH (default: the first <svg viewBox>, else 1920x1080)")
+    ap.add_argument("--size", help="viewport WxH (default: the viewBox of <svg id="stage">, else the first <svg viewBox>, else 1920x1080)")
     ap.add_argument("--width", type=int, help="scale the output video to this width")
     ap.add_argument("--crf", type=int, default=16)
     ap.add_argument("--root", help="folder to serve (default: the page's folder)")
diff --git a/tests/test_stage_size.py b/tests/test_stage_size.py
new file mode 100644
index 0000000..28220dd
--- /dev/null
+++ b/tests/test_stage_size.py
@@ -0,0 +1,44 @@
+#!/usr/bin/env python3
+"""Unit tests for _m2c.stage_size (stdlib only).
+
+  python3 tests/test_stage_size.py
+"""
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent / "skills" / "motion2code" / "scripts"))
+from _m2c import stage_size  # noqa: E402
+
+
+def size_of(html: str):
+    with tempfile.NamedTemporaryFile("w", suffix=".html", delete=False) as f:
+        f.write(html)
+    try:
+        return stage_size(f.name)
+    finally:
+        Path(f.name).unlink()
+
+
+class StageSize(unittest.TestCase):
+    def test_plain_stage(self):
+        self.assertEqual(size_of('<svg id="stage" viewBox="0 0 1080 1920"></svg>'), (1080, 1920))
+
+    def test_stage_after_icon_sprite(self):
+        html = ('<svg class="icon" viewBox="0 0 24 24"><path d="M0 0"/></svg>'
+                '<svg id="stage" viewBox="0 0 1080 1920"></svg>')
+        self.assertEqual(size_of(html), (1080, 1920))
+
+    def test_single_quoted_viewbox(self):
+        self.assertEqual(size_of("<svg id='stage' viewBox='0 0 1080 1920'></svg>"), (1080, 1920))
+
+    def test_no_stage_id_uses_first_svg(self):
+        self.assertEqual(size_of('<svg viewBox="0 0 800 600"></svg>'), (800, 600))
+
+    def test_fallback(self):
+        self.assertEqual(size_of("<div></div>"), (1920, 1080))
+
+
+if __name__ == "__main__":
+    unittest.main()