LiipImagineBundle placeholder outline filter

PlaceholderOutlineFilter.php

<?php

namespace App\Service;

use Imagine\Image\Box;
use Imagine\Image\ImageInterface;
use Imagine\Image\Point;
use Liip\ImagineBundle\Imagine\Filter\Loader\LoaderInterface;

class PlaceholderOutlineFilter implements LoaderInterface
{
    /**
     * Extends the image by 1 pixel in all directions using the current border colors.
     */
    public function load(ImageInterface $image, array $options = []): ImageInterface
    {
        $width = $image->getSize()->getWidth() + 2;
        $height = $image->getSize()->getHeight() + 2;
        $newSize = new Box($width, $height);

        $originalImage = $image->copy();

        $image->resize($newSize);

        $pastePoints = [
            [0, 0], // corners first
            [2, 0],
            [0, 2],
            [2, 2],
            [1, 0], // edges
            [0, 1],
            [2, 1],
            [1, 2],
            [1, 1], // center
        ];

        foreach ($pastePoints as $pastePoint) {
            $point = new Point($pastePoint[0], $pastePoint[1]);
            $image->paste($originalImage, $point);
        }

        return $image;
    }
}

services.yaml

services:
  App\Service\PlaceholderOutlineFilter:
    tags:
      - { name: "liip_imagine.filter.loader", loader: placeholder }