Refactor code

src/Drivers/Gd/Encoders/PngEncoder.php

@@ -4,41 +4,30 @@
 
 namespace Intervention\Image\Drivers\Gd\Encoders;
 
-use GdImage;
 use Intervention\Image\EncodedImage;
 use Intervention\Image\Encoders\PngEncoder as GenericPngEncoder;
-use Intervention\Image\Exceptions\RuntimeException;
 use Intervention\Image\Interfaces\ImageInterface;
 use Intervention\Image\Interfaces\SpecializedInterface;
 
 class PngEncoder extends GenericPngEncoder implements SpecializedInterface
 {
     public function encode(ImageInterface $image): EncodedImage
     {
-        $output = $this->maybeToPalette(clone $image); // use clone because colors may be reduced
+        // use clone because colors may be reduced and original
+        // image should not be altered by encoder
+        $output = clone $image;
 
-        $data = $this->buffered(function () use ($output) {
-            imageinterlace($output, $this->interlaced);
-            imagesavealpha($output, true);
-            imagepng($output, null, -1);
+        if ($this->indexed) {
+            $output->reduceColors(256)->core()->native();
+        }
+
+        $gd = $output->core()->native();
+        $data = $this->buffered(function () use ($gd) {
+            imageinterlace($gd, $this->interlaced);
+            imagesavealpha($gd, true);
+            imagepng($gd, null, -1);
         });
 
         return new EncodedImage($data, 'image/png');
     }
-
-    /**
-     * Transform given image to indexed palette version according to encoder settings
-     *
-     * @param ImageInterface $image
-     * @throws RuntimeException
-     * @return GdImage
-     */
-    private function maybeToPalette(ImageInterface $image): GdImage
-    {
-        if ($this->indexed === false) {
-            return $image->core()->native();
-        }
-
-        return $image->reduceColors(256)->core()->native();
-    }
 }