settings.php

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Provides some custom settings for the certificate module
 *
 * @package    mod
 * @subpackage simplecertificate
 * @copyright  Carlos Alexandre S. da Fonseca <carlos.alexandre@outlook.com>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

defined('MOODLE_INTERNAL') || die;

if ($ADMIN->fulltree) {
    require_once("$CFG->dirroot/mod/simplecertificate/lib.php");

    // General settings.
    $settings->add(new admin_setting_configtext('simplecertificate/width', get_string('defaultwidth', 'simplecertificate'),
        get_string('size_help', 'simplecertificate'), 297, PARAM_INT));
    $settings->add(new admin_setting_configtext('simplecertificate/height', get_string('defaultheight', 'simplecertificate'),
        get_string('size_help', 'simplecertificate'), 210, PARAM_INT));

    $settings->add(new admin_setting_configtext('simplecertificate/certificatetextx',
                    get_string('defaultcertificatetextx', 'simplecertificate'),
        get_string('textposition_help', 'simplecertificate'), 50, PARAM_INT));
    $settings->add(new admin_setting_configtext('simplecertificate/certificatetexty',
                    get_string('defaultcertificatetexty', 'simplecertificate'),
        get_string('textposition_help', 'simplecertificate'), 50, PARAM_INT));

    $settings->add(new admin_setting_configselect('simplecertificate/certdate', get_string('printdate', 'simplecertificate'),
        get_string('printdate_help', 'simplecertificate'), -2, simplecertificate_get_date_options()));


    $settings->add(new admin_setting_configtext('simplecertificate/certlifetime', get_string('certlifetime', 'simplecertificate'),
        get_string('certlifetime_help', 'simplecertificate'), 60, PARAM_INT));

    // QR CODE.
    $settings->add(new admin_setting_configcheckbox('simplecertificate/printqrcode',
        get_string('printqrcode', 'simplecertificate'), get_string('printqrcode_help', 'simplecertificate'), 1));
    $settings->add(new admin_setting_configtext('simplecertificate/codex', get_string('defaultcodex', 'simplecertificate'),
        get_string('qrcodeposition_help', 'simplecertificate'), 10, PARAM_INT));
    $settings->add(new admin_setting_configtext('simplecertificate/codey', get_string('defaultcodey', 'simplecertificate'),
        get_string('qrcodeposition_help', 'simplecertificate'), 10, PARAM_INT));
    $settings->add(new admin_setting_configcheckbox('simplecertificate/qrcodefirstpage',
            get_string('qrcodefirstpage', 'simplecertificate'), get_string('qrcodefirstpage_help', 'simplecertificate'), 0));

    // Certificate back page.
    $settings->add(new admin_setting_configcheckbox('simplecertificate/enablesecondpage',
            get_string('enablesecondpage', 'simplecertificate'), get_string('enablesecondpage_help', 'simplecertificate'), 0));

    // Pagination.
    $settings->add(new admin_setting_configtext('simplecertificate/perpage', get_string('defaultperpage', 'simplecertificate'),
            get_string('defaultperpage_help', 'simplecertificate'), 30, PARAM_INT));


}