From a44b98c3588ef6f18f77e76abc93d7ab493116bf Mon Sep 17 00:00:00 2001
From: lumiscosity <averyrudelphe@gmail.com>
Date: Thu, 4 Sep 2025 09:08:37 +0200
Subject: [PATCH] script: preserve 2D on DOMMatrix invert (#39113)

More small geometry fixes.

Testing: Covered by WPT
(css/geometry/DOMMatrix-invert-preserves-2d.html)

---------

Signed-off-by: lumiscosity <averyrudelphe@gmail.com>
---
 components/script/dom/dommatrixreadonly.rs       | 16 +++++++++++-----
 .../DOMMatrix-invert-preserves-2d.html.ini       |  3 ---
 2 files changed, 11 insertions(+), 8 deletions(-)
 delete mode 100644 tests/wpt/meta/css/geometry/DOMMatrix-invert-preserves-2d.html.ini

diff --git a/components/script/dom/dommatrixreadonly.rs b/components/script/dom/dommatrixreadonly.rs
index d53bceb8f43..aa0aae18764 100644
--- a/components/script/dom/dommatrixreadonly.rs
+++ b/components/script/dom/dommatrixreadonly.rs
@@ -409,12 +409,18 @@ impl DOMMatrixReadOnly {
         // Step 2 in DOMMatrix.SkewYSelf
     }
 
-    // https://drafts.fxtf.org/geometry-1/#dom-dommatrix-invertself
+    /// <https://drafts.fxtf.org/geometry-1/#dom-dommatrix-invertself>
     pub(crate) fn invert_self(&self) {
         let mut matrix = self.matrix.borrow_mut();
-        // Step 1.
-        *matrix = matrix.inverse().unwrap_or_else(|| {
-            // Step 2.
+        // Step 1. Invert the current matrix.
+        let inverted = match self.is2D() {
+            true => matrix.to_2d().inverse().map(|m| m.to_3d()),
+            false => matrix.inverse(),
+        };
+
+        // Step 2. If the current matrix is not invertible set all attributes to NaN
+        // and set is 2D to false.
+        *matrix = inverted.unwrap_or_else(|| -> Transform3D<f64> {
             self.is2D.set(false);
             Transform3D::new(
                 f64::NAN,
@@ -434,7 +440,7 @@ impl DOMMatrixReadOnly {
                 f64::NAN,
                 f64::NAN,
             )
-        })
+        });
         // Step 3 in DOMMatrix.InvertSelf
     }
 }
diff --git a/tests/wpt/meta/css/geometry/DOMMatrix-invert-preserves-2d.html.ini b/tests/wpt/meta/css/geometry/DOMMatrix-invert-preserves-2d.html.ini
deleted file mode 100644
index 36eb63e7acf..00000000000
--- a/tests/wpt/meta/css/geometry/DOMMatrix-invert-preserves-2d.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[DOMMatrix-invert-preserves-2d.html]
-  [scale]
-    expected: FAIL