From c080f17266c4fb8c5cba57ef17cca31c92f95eb9 Mon Sep 17 00:00:00 2001
From: Till Berger <till@mellthas.de>
Date: Sat, 11 Jun 2022 12:28:34 +0200
Subject: [PATCH] Always return a list for the `transform` property

---
 src/Css/Style.php |  6 +++---
 src/Renderer.php  | 10 ++++++----
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/Css/Style.php b/src/Css/Style.php
index 10953737a..c310b7ff5 100644
--- a/src/Css/Style.php
+++ b/src/Css/Style.php
@@ -153,7 +153,7 @@
  * @property float|string    $text_indent                 Length in pt or a percentage value
  * @property string          $text_transform
  * @property float|string    $top                         Length in pt, a percentage value, or `auto`
- * @property array           $transform
+ * @property array           $transform                   List of transforms
  * @property array           $transform_origin
  * @property string          $unicode_bidi
  * @property string          $unicode_range
@@ -3440,7 +3440,7 @@ protected function _compute_size(string $val)
 
     /**
      * @param string $computed
-     * @return array|null
+     * @return array
      *
      * @link https://www.w3.org/TR/css-transforms-1/#transform-property
      */
@@ -3453,7 +3453,7 @@ protected function _get_transform($computed)
         $angle = "\s*([^,\s]+(?:deg|rad)?)\s*";
 
         if (!preg_match_all("/[a-z]+\([^\)]+\)/i", $computed, $parts, PREG_SET_ORDER)) {
-            return null;
+            return [];
         }
 
         $functions = [
diff --git a/src/Renderer.php b/src/Renderer.php
index d7ff8b9de..36966fb38 100644
--- a/src/Renderer.php
+++ b/src/Renderer.php
@@ -65,19 +65,21 @@ public function render(Frame $frame)
 
         $style = $frame->get_style();
 
-        if (in_array($style->visibility, ["hidden", "collapse"])) {
+        if (in_array($style->visibility, ["hidden", "collapse"], true)) {
             return;
         }
 
         $display = $style->display;
+        $transformList = $style->transform;
+        $hasTransform = $transformList !== [];
 
         // Starts the CSS transformation
-        if ($style->transform && is_array($style->transform)) {
+        if ($hasTransform) {
             $this->_canvas->save();
             list($x, $y) = $frame->get_padding_box();
             $origin = $style->transform_origin;
 
-            foreach ($style->transform as $transform) {
+            foreach ($transformList as $transform) {
                 list($function, $values) = $transform;
                 if ($function === "matrix") {
                     $function = "transform";
@@ -200,7 +202,7 @@ public function render(Frame $frame)
             $this->_canvas->clipping_end();
         }
 
-        if ($style->transform && is_array($style->transform)) {
+        if ($hasTransform) {
             $this->_canvas->restore();
         }