From e5b9aa71fb5e1153e9819183f3d3b3b6a0efae54 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Top=C3=B3r?= <toporek16@gmail.com>
Date: Mon, 6 Apr 2026 18:37:07 +0200
Subject: [PATCH] Add prefixing support for mask-position-x and mask-position-y

Add -webkit-mask-position-x and -webkit-mask-position-y to the
css-masks feature prefix list. These properties have 97%+ global
browser support and were missing from the prefixer.

Closes #1537
---
 data/prefixes.js                 | 2 ++
 test/autoprefixer.test.js        | 4 ++++
 test/cases/mask-position.css     | 5 +++++
 test/cases/mask-position.out.css | 8 ++++++++
 4 files changed, 19 insertions(+)
 create mode 100644 test/cases/mask-position.css
 create mode 100644 test/cases/mask-position.out.css

diff --git a/data/prefixes.js b/data/prefixes.js
index e4e26b5d0..073a78c93 100644
--- a/data/prefixes.js
+++ b/data/prefixes.js
@@ -750,6 +750,8 @@ f(prefixCssMasks, browsers => {
     [
       'mask',
       'mask-position',
+      'mask-position-x',
+      'mask-position-y',
       'mask-size',
       'mask-border',
       'mask-border-outset',
diff --git a/test/autoprefixer.test.js b/test/autoprefixer.test.js
index 658b1aafc..4da9fd6c3 100644
--- a/test/autoprefixer.test.js
+++ b/test/autoprefixer.test.js
@@ -817,6 +817,10 @@ test('supports mask-composite', () => {
   check('mask-composite')
 })
 
+test('supports mask-position-x and mask-position-y', () => {
+  check('mask-position')
+})
+
 test('supports image-set()', () => {
   check('image-set')
 })
diff --git a/test/cases/mask-position.css b/test/cases/mask-position.css
new file mode 100644
index 000000000..c0415a511
--- /dev/null
+++ b/test/cases/mask-position.css
@@ -0,0 +1,5 @@
+a {
+  mask-position: center;
+  mask-position-x: 10px;
+  mask-position-y: 20px;
+}
diff --git a/test/cases/mask-position.out.css b/test/cases/mask-position.out.css
new file mode 100644
index 000000000..7942add0d
--- /dev/null
+++ b/test/cases/mask-position.out.css
@@ -0,0 +1,8 @@
+a {
+  -webkit-mask-position: center;
+          mask-position: center;
+  -webkit-mask-position-x: 10px;
+          mask-position-x: 10px;
+  -webkit-mask-position-y: 20px;
+          mask-position-y: 20px;
+}