only run imagedestroy on resources

On PHP 8+, the GD library no longer works on resources that need to be
manually destroyed. Instead Image objects are passed around that are
automatically garbage collected.

Author: splitbrain

phpunit.xml

@@ -1,23 +1,23 @@
 <?xml version="1.0" encoding="UTF-8"?>
-
-<phpunit backupGlobals="false"
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"
+         backupGlobals="false"
          backupStaticAttributes="false"
-         bootstrap="vendor/autoload.php"
+         bootstrap="tests/bootstrap.php"
          colors="true"
          convertErrorsToExceptions="true"
          convertNoticesToExceptions="true"
          convertWarningsToExceptions="true"
          processIsolation="false"
          stopOnFailure="false">
-
+    <coverage processUncoveredFiles="true">
+        <include>
+            <directory suffix=".php">./src/</directory>
+        </include>
+    </coverage>
     <testsuites>
         <testsuite name="all">
             <directory suffix="Test.php">./tests</directory>
         </testsuite>
     </testsuites>
-    <filter>
-        <whitelist processUncoveredFilesFromWhitelist="true">
-            <directory suffix=".php">./src/</directory>
-        </whitelist>
-    </filter>
 </phpunit>

src/GdAdapter.php

@@ -30,6 +30,7 @@ public function __construct($imagepath, $options = [])
      */
     public function __destruct()
     {
+        // destroy the GD image resource (only needed on PHP < 8.0)
         if (is_resource($this->image)) {
             imagedestroy($this->image);
         }
@@ -106,7 +107,7 @@ public function rotate($orientation)
             imageflip($image, IMG_FLIP_HORIZONTAL);
         }
 
-        imagedestroy($this->image);
+        $this->__destruct(); // destroy old image
         $this->image = $image;
 
         //keep png alpha channel if possible
@@ -163,7 +164,7 @@ public function save($path, $extension = '')
             $saver($this->image, $path);
         }
 
-        imagedestroy($this->image);
+        $this->__destruct();
     }
 
     /**
@@ -436,7 +437,7 @@ protected function resizeOperation($toWidth, $toHeight, $offsetX = 0, $offsetY =
         }
 
         // destroy original GD image ressource and replace with new one
-        imagedestroy($this->image);
+        $this->__destruct();
         $this->image = $newimg;
         $this->width = $toWidth;
         $this->height = $toHeight;

tests/TestCase.php

@@ -99,7 +99,9 @@ public function getColor($path, $position)
         $image = $opener($path);
         $rgb = imagecolorat($image, $x, $y);
         $found = imagecolorsforindex($image, $rgb);
-        imagedestroy($image);
+        if(is_resource($image)) {
+            imagedestroy($image);
+        }
         return $found;
     }