From 815969f4d08a5c81282f53da214209eda7b0284c Mon Sep 17 00:00:00 2001
From: Elena Torro <elenatorro@gmail.com>
Date: Wed, 10 Jun 2026 13:22:44 +0200
Subject: [PATCH] :zap: drop identity matrices before FFI output

---
 render-wasm/src/shapes/modifiers.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/render-wasm/src/shapes/modifiers.rs b/render-wasm/src/shapes/modifiers.rs
index 3da9bd73fb..613681785e 100644
--- a/render-wasm/src/shapes/modifiers.rs
+++ b/render-wasm/src/shapes/modifiers.rs
@@ -498,8 +498,11 @@ pub fn propagate_modifiers(
         }
     }
 
+    // Drop identity matrices: the reflow-mark inserts a no-op entry for every
+    // descendant of a reflowed subtree; emitting them floods the FFI output.
     Ok(modifiers
         .iter()
+        .filter(|(_, val)| !identitish(val))
         .map(|(key, val)| TransformEntry::from_input(*key, *val))
         .collect())
 }