Desaturate.php

<?php

namespace Drupal\system\Plugin\ImageToolkit\Operation\gd;


/**
 * Defines GD2 Desaturate operation.
 *
 * @ImageToolkitOperation(
 *   id = "gd_desaturate",
 *   toolkit = "gd",
 *   operation = "desaturate",
 *   label = @Translation("Desaturate"),
 *   description = @Translation("Converts an image to grayscale.")
 * )
 */
class Desaturate extends GDImageToolkitOperationBase {
    
    /**
     * {@inheritdoc}
     */
    protected function arguments() {
        // This operation does not use any parameters.
        return [];
    }
    
    /**
     * {@inheritdoc}
     */
    protected function execute(array $arguments) {
        // PHP installations using non-bundled GD do not have imagefilter.
        if (!function_exists('imagefilter')) {
            $this->logger
                ->notice("The image '@file' could not be desaturated because the imagefilter() function is not available in this PHP installation.", [
                '@file' => $this->getToolkit()
                    ->getSource(),
            ]);
            return FALSE;
        }
        return imagefilter($this->getToolkit()
            ->getResource(), IMG_FILTER_GRAYSCALE);
    }

}