DesaturateImageEffect.php

<?php

namespace Drupal\image\Plugin\ImageEffect;

use Drupal\Core\Image\ImageInterface;
use Drupal\image\ImageEffectBase;

/**
 * Desaturates (grayscale) an image resource.
 *
 * @ImageEffect(
 *   id = "image_desaturate",
 *   label = @Translation("Desaturate"),
 *   description = @Translation("Desaturate converts an image to grayscale.")
 * )
 */
class DesaturateImageEffect extends ImageEffectBase {
    
    /**
     * {@inheritdoc}
     */
    public function applyEffect(ImageInterface $image) {
        if (!$image->desaturate()) {
            $this->logger
                ->error('Image desaturate failed using the %toolkit toolkit on %path (%mimetype, %dimensions)', [
                '%toolkit' => $image->getToolkitId(),
                '%path' => $image->getSource(),
                '%mimetype' => $image->getMimeType(),
                '%dimensions' => $image->getWidth() . 'x' . $image->getHeight(),
            ]);
            return FALSE;
        }
        return TRUE;
    }

}