Method execute

/**
 * Method to apply a filter to an image resource.
 *
 * @param   array  $options  An array of options for the filter.
 *
 * @return  void
 *
 * @since   2.5.0
 * @throws  \InvalidArgumentException
 */
public function execute(array $options = [])
{
    // Validate that the contrast value exists and is an integer.
    if (!isset($options[IMG_FILTER_CONTRAST]) || !\is_int($options[IMG_FILTER_CONTRAST])) {
        throw new \InvalidArgumentException('No valid contrast value was given.  Expected integer.');
    }
    // Perform the contrast filter.
    imagefilter($this->handle, IMG_FILTER_CONTRAST, $options[IMG_FILTER_CONTRAST]);
}