nstdio / SVGMagick

        }

    }

    public static function gamma(ContainerInterface $container, $amplitude, $exponent, $offset = 0, $filterId = null)

    {

        $config = ['id' => $filterId, 'type' => __FUNCTION__];

        self::buildConfig($config, [

            'amplitude' => $amplitude,

            'exponent'  => $exponent,

            'offset'    => $offset,

        ]);

        return self::createAndAppend($container, $config);

    }

    public static function brightness(ContainerInterface $container, $amount, $filterId = null)

    {

        return self::createAndAppend($container, $config);

    }

    public static function contrast(ContainerInterface $container, $amount, $filterId = null)

    {

        $config = ['id' => $filterId, 'type' => 'linear'];

        $intercept = 0.5 - (0.5 * $amount);

        self::buildConfig($config, [

            'slope'     => $amount,

            'intercept' => $intercept,

        ]);

        return self::createAndAppend($container, $config);

    }

}