void tool_brightness::execute(Magick::Image &img)
{

    using_slider* param = (using_slider*) get_para();

    try{
        img.brightnessContrast(param->get_slider_val()*1.0, 0.0);
    }catch(Magick::Warning){
        //Det er denne exception som normalt blir eksekvert hved feil i ImageMagick
        err_listener->on_exception_occured(TOOLIDENT::BRIGTHEN, ERRORTYPE::WARNING);
    }catch(Magick::Error &error){
        err_listener->on_exception_occured(TOOLIDENT::BRIGTHEN, ERRORTYPE::MAGICK_EXCEPTION);
    }catch(std::exception &error){
        err_listener->on_exception_occured(TOOLIDENT::BRIGTHEN, ERRORTYPE::STDEXCEPTION);
    }
}
int main(int argc, char *argv[]) {
    char var[VARLEN];
    int maxlen = VARLEN;
    int first_n = 0;
    struct gp* groups = NULL;
    
    /* get parameter */
    if ((first_n = get_para(argc, argv)) < 0) {
        printf ("%s: input group flag n.\n", argv[0]);
        return -1;
    }

    while (readvar(var, maxlen) > 0) {
        add_to_groups(groups, var, first_n);
    }

    print_groups(groups);
    return 0;
}