From 81548edff996104a48b22b1d3c69a64d6e532cda Mon Sep 17 00:00:00 2001
From: NetterSilver <133535268+Silvertree2010@users.noreply.github.com>
Date: Mon, 19 Oct 2026 20:22:36 +0200
Subject: [PATCH] Resolve SVG font-size percentages against the parent font
 size

Found while testing crates/svg/src/lib.rs:624

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
---
 crates/svg/src/lib.rs   |  6 +++++-
 crates/svg/src/tests.rs | 15 +++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/crates/svg/src/lib.rs b/crates/svg/src/lib.rs
index 24cc584e0..82ab5943f 100644
--- a/crates/svg/src/lib.rs
+++ b/crates/svg/src/lib.rs
@@ -621,7 +621,11 @@ impl<'a, 'i> Parser<'a, 'i> {
         if let Some(c) = d.get("color").and_then(|v| parse_color(v)) {
             st.color = c;
         }
-        if let Some(v) = d.get("font-size").and_then(|v| self.length(v, 'o', st.font_size)) {
+        let font_size = d.get("font-size").and_then(|v| match v.trim().strip_suffix('%') {
+            Some(p) => p.trim().parse::<f64>().ok().map(|p| p / 100.0 * st.font_size),
+            None => self.length(v, 'o', st.font_size),
+        });
+        if let Some(v) = font_size.filter(|v| v.is_finite()) {
             st.font_size = v;
         }
         if let Some(p) = d.get("fill").and_then(|v| self.paint_ref(v)) {
diff --git a/crates/svg/src/tests.rs b/crates/svg/src/tests.rs
index 93db715c1..5c5838ebd 100644
--- a/crates/svg/src/tests.rs
+++ b/crates/svg/src/tests.rs
@@ -277,3 +277,18 @@ fn a_symbol_used_a_thousand_times_still_imports() {
     let doc = parse(svg.as_bytes()).unwrap();
     assert_eq!(depth_and_shapes(&doc.root).1, 3000);
 }
+
+#[test]
+fn font_size_percentage_resolves_against_the_parent_font_size() {
+    for (body, expected) in [
+        (r#"<g font-size="200%"><rect width="1em" height="1em"/></g>"#, 32.0),
+        (r#"<g font-size="200%"><rect width="2ex" height="1em"/></g>"#, 32.0),
+        (r#"<g font-size="200%"><g font-size="200%"><rect width="1em" height="1em"/></g></g>"#, 64.0),
+    ] {
+        let svg = format!(r#"<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100">{body}</svg>"#);
+        let d = parse(svg.as_bytes()).unwrap();
+        let shapes = d.flatten();
+        assert_eq!(shapes.len(), 1);
+        assert!(matches!(shapes[0].2.geom, Geom::Rect { w, .. } if w == expected), "{body}: {:?}", shapes[0].2.geom);
+    }
+}