apply (Imlib2::Image)

    /*
     * Apply an Imlib2::ColorModifier to the image
     *
     * Examples:
     *   # modify the contrast of the entire image
     *   cmod = Imlib2::ColorModifier.new
     *   cmod.contrast = 1.5
     *   image.apply_cmod color_mod
     *
     *   # adjust the gamma of the given rect
     *   cmod = Imlib2::ColorModifier.new
     *   cmod.gamma = 0.5
     *   rect = [10, 10, 20, 40]
     *   image.apply_color_modifier cmod, rect
     *
     */
    static VALUE image_apply_cmod(int argc, VALUE *argv, VALUE self) {