Adding the addFrame method to ImageMedium (#3323)

* Update ImageMediaTrait.php

Add needed magic actions to enable image frame creation.

* Update ImageMedium.php

Adds addFrame method that can be (recursively) called from Twig.

system/src/Grav/Common/Media/Traits/ImageMediaTrait.php

@@ -56,7 +56,7 @@ trait ImageMediaTrait
         'resize', 'forceResize', 'cropResize', 'crop', 'zoomCrop',
         'negate', 'brightness', 'contrast', 'grayscale', 'emboss',
         'smooth', 'sharp', 'edge', 'colorize', 'sepia', 'enableProgressive',
-        'rotate', 'flip', 'fixOrientation', 'gaussianBlur', 'format'
+        'rotate', 'flip', 'fixOrientation', 'gaussianBlur', 'format', 'create', 'fill', 'merge'
     ];
 
     /** @var array */

system/src/Grav/Common/Page/Medium/ImageMedium.php

@@ -337,6 +337,37 @@ class ImageMedium extends Medium implements ImageMediaInterface, ImageManipulate
         return $this;
     }
 
+    /**
+     * Add a frame to image
+     *
+     * @return $this
+     */
+    public function addFrame(int $border = 10, string $color = '0x000000')
+    {
+      if(is_int(intval($border)) && $border>0 && preg_match('/^0x[a-f0-9]{6}$/i', $color)) { // $border must be an integer and bigger than 0; $color must be formatted as an HEX value (0x??????).
+        $image = ImageFile::open($this->path());
+      }
+      else {
+        return $this;
+      }
+
+      $dst_width = $image->width()+2*$border;
+      $dst_height = $image->height()+2*$border;
+
+      $frame = ImageFile::create($dst_width, $dst_height);
+
+      $frame->__call('fill', [$color]);
+
+      $this->image = $frame;
+
+      $this->__call('merge', [$image, $border, $border]);
+
+      $this->saveImage();
+
+      return $this;
+
+    }
+
     /**
      * Forward the call to the image processing method.
      *
@@ -344,6 +375,7 @@ class ImageMedium extends Medium implements ImageMediaInterface, ImageManipulate
      * @param mixed $args
      * @return $this|mixed
      */
+    
     public function __call($method, $args)
     {
         if (!in_array($method, static::$magic_actions, true)) {