ResizeModifier

src/Drivers/Abstract/AbstractImage.php

@@ -101,4 +101,11 @@ abstract class AbstractImage
             $this->resolveDriverClass('Modifiers\BlurModifier', $amount)
         );
     }
+
+    public function resize(int $width, int $height): ImageInterface
+    {
+        return $this->modify(
+            $this->resolveDriverClass('Modifiers\ResizeModifier', $width, $height)
+        );
+    }
 }

src/Drivers/Gd/Modifiers/ResizeModifier.php

@@ -0,0 +1,80 @@
+<?php
+
+namespace Intervention\Image\Drivers\Gd\Modifiers;
+
+use Intervention\Image\Interfaces\FrameInterface;
+use Intervention\Image\Interfaces\ImageInterface;
+use Intervention\Image\Interfaces\ModifierInterface;
+
+class ResizeModifier implements ModifierInterface
+{
+    protected $width;
+    protected $height;
+
+    public function __construct(int $width, int $height)
+    {
+        $this->width = $width;
+        $this->height = $height;
+    }
+
+    public function apply(ImageInterface $image): ImageInterface
+    {
+        foreach ($image as $frame) {
+            $this->modify($frame->getCore(), 0, 0, 0, 0, $this->width, $this->height, $image->getWidth(), $image->getHeight());
+        }
+
+        return $image;
+    }
+
+    /**
+     * Wrapper function for 'imagecopyresampled'
+     *
+     * @param  Image   $image
+     * @param  int     $dst_x
+     * @param  int     $dst_y
+     * @param  int     $src_x
+     * @param  int     $src_y
+     * @param  int     $dst_w
+     * @param  int     $dst_h
+     * @param  int     $src_w
+     * @param  int     $src_h
+     * @return boolean
+     */
+    protected function modify($gd, $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h)
+    {
+        // create new image
+        $modified = imagecreatetruecolor($dst_w, $dst_h);
+
+        // preserve transparency
+        $transIndex = imagecolortransparent($gd);
+
+        if ($transIndex != -1) {
+            $rgba = imagecolorsforindex($modified, $transIndex);
+            $transColor = imagecolorallocatealpha($modified, $rgba['red'], $rgba['green'], $rgba['blue'], 127);
+            imagefill($modified, 0, 0, $transColor);
+            imagecolortransparent($modified, $transColor);
+        } else {
+            imagealphablending($modified, false);
+            imagesavealpha($modified, true);
+        }
+
+        // copy content from gd
+        $result = imagecopyresampled(
+            $modified,
+            $gd,
+            $dst_x,
+            $dst_y,
+            $src_x,
+            $src_y,
+            $dst_w,
+            $dst_h,
+            $src_w,
+            $src_h
+        );
+
+        // set new content as recource
+        $image->setCore($modified);
+
+        return $result;
+    }
+}