class ColorizeImageEffect

class ColorizeImageEffect extends ConfigurableImageEffectBase {
    
    /**
     * {@inheritdoc}
     */
    public function applyEffect(ImageInterface $image) {
        $data = $this->configuration;
        // Verify that Drupal is using the PHP GD library for image manipulations
        // since this effect depends on functions implemented by the GD extension.
        if ($image->getToolkitId() != 'gd') {
            $this->logger
                ->info('Image colorize failed on %file. The image does not use the GD toolkit.', [
                '%file' => $image->getSource(),
            ]);
            return FALSE;
        }
        // phpcs:disable Drupal.Commenting.InlineComment.InvalidEndChar
        // Not all GD installations are created equal. It is a good idea to check
        // for the existence of image manipulation functions before using them.
        // PHP installations using non-bundled GD do not have imagefilter(). See the
        // @link http://www.php.net/manual/en/book.image.php PHP manual @endlink for
        // more information about image manipulation functions.
        // phpcs:enable
        if (!function_exists('imagefilter')) {
            $this->logger
                ->error('The image %image could not be colorized because the imagefilter() function is not available in this PHP installation.', [
                '%file' => $image->getSource(),
            ]);
            return FALSE;
        }
        if (!Color::validateHex($data['color'])) {
            // Use the default value, if the stored value is invalid.
            $data['color'] = '#FF6633';
        }
        $rgb = Color::hexToRgb($data['color']);
        // $source contains the \GdImage instance passed to GD functions.
        // This line only works with the GD toolkit implemented by Drupal core.
        // Other toolkits could not implement getImage(), or that method could
        // return a different value.
        $source = $image->getToolkit()
            ->getImage();
        // First desaturate the image, and then apply the new color.
        imagefilter($source, IMG_FILTER_GRAYSCALE);
        imagefilter($source, IMG_FILTER_COLORIZE, $rgb['red'], $rgb['green'], $rgb['blue']);
        return TRUE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getSummary() {
        if (Color::validateHex($this->configuration['color'])) {
            $color = $this->configuration['color'];
        }
        else {
            // Use the default value, if the stored value is invalid.
            $color = '#FF6633';
        }
        $summary = [
            '#markup' => $color,
        ];
        $summary += parent::getSummary();
        return $summary;
    }
    
    /**
     * {@inheritdoc}
     */
    public function defaultConfiguration() {
        return [
            'color' => '#FF6633',
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
        // You do not need to worry about saving/updating/deleting the collected
        // data. The Image module will automatically serialize and store all the
        // data associated with an effect.
        $form['color'] = [
            '#type' => 'textfield',
            '#title' => $this->t('Color'),
            '#description' => $this->t('The color to use when colorizing the image. Use web-style hex colors, for example %long-value, or %short-value.', [
                '%long-value' => '#FF6633',
                '%short-value' => 'F63',
            ]),
            '#default_value' => $this->configuration['color'] ?? '',
            '#size' => 7,
            '#max_length' => 7,
            '#required' => TRUE,
        ];
        return $form;
    }

}