ponepaste/includes/captcha.php

<?php

use JetBrains\PhpStorm\ArrayShape;

#[ArrayShape(['code' => "mixed|string", 'image_src' => "string"])]
function captcha($color, $mode, $mul, $allowed) : array {
    $bg_path = __DIR__ . '/../public/assets/img/captcha/';
    $font_path = __DIR__ . '/../public/assets/fonts/';

    if ($mul == "on") {
        $captcha_config = array(
            'code' => '',
            'min_length' => 5,
            'max_length' => 6,
            'backgrounds' => array(
                $bg_path . 'text3.png',
                $bg_path . 'text2.png',
                $bg_path . 'text1.png'
            ),
            'fonts' => array(
                $font_path . 'LMS Pretty Pony.ttf',
                $font_path . 'PonyvilleMedium0.4.ttf',
                $font_path . 'PonyvilleMedium0.4.ttf'
            ),
            'characters' => $allowed,
            'min_font_size' => 20,
            'max_font_size' => 28,
            'color' => $color,
            'angle_min' => 0,
            'angle_max' => 5,
            'shadow' => true,
            'shadow_color' => '#fff',
            'shadow_offset_x' => -2,
            'shadow_offset_y' => 4
        );
    } else {
        $captcha_config = array(
            'code' => '',
            'min_length' => 5,
            'max_length' => 5,
            'backgrounds' => array(
                $bg_path . 'text2.png'
            ),
            'fonts' => array(
                $font_path . 'times_new_yorker.ttf'
            ),
            'characters' => $allowed,
            'min_font_size' => 28,
            'max_font_size' => 28,
            'color' => $color,
            'angle_min' => 0,
            'angle_max' => 10,
            'shadow' => true,
            'shadow_color' => '#fff',
            'shadow_offset_x' => -1,
            'shadow_offset_y' => 1
        );
    }

    // Overwrite defaults with custom config values
    if (!empty($config) && is_array($config)) {
        foreach ($config as $key => $value)
            $captcha_config[$key] = $value;
    }

    // Restrict certain values
    if ($captcha_config['min_length'] < 1)
        $captcha_config['min_length'] = 1;
    if ($captcha_config['angle_min'] < 0)
        $captcha_config['angle_min'] = 0;
    if ($captcha_config['angle_max'] > 10)
        $captcha_config['angle_max'] = 10;
    if ($captcha_config['angle_max'] < $captcha_config['angle_min'])
        $captcha_config['angle_max'] = $captcha_config['angle_min'];
    if ($captcha_config['min_font_size'] < 10)
        $captcha_config['min_font_size'] = 10;
    if ($captcha_config['max_font_size'] < $captcha_config['min_font_size'])
        $captcha_config['max_font_size'] = $captcha_config['min_font_size'];


    // Generate CAPTCHA code if not set by user
    if (empty($captcha_config['code'])) {
        $captcha_config['code'] = '';
        $length = rand($captcha_config['min_length'], $captcha_config['max_length']);
        while (strlen($captcha_config['code']) < $length) {
            $captcha_config['code'] .= substr($captcha_config['characters'], rand() % (strlen($captcha_config['characters'])), 1);
        }
    }

    // Generate HTML for image src
    $image_src = '/captcha?_CAPTCHA&_R=' . urlencode(rand());

    $_SESSION['_CAPTCHA']['config'] = serialize($captcha_config);

    return [
        'code' => $captcha_config['code'],
        'image_src' => $image_src
    ];
}

if (!function_exists('hex2rgb')) {
    function hex2rgb($hex_str) : array|null {
        $hex_str = preg_replace("/[^0-9A-Fa-f]/", '', $hex_str); // Gets a proper hex string

        if (strlen($hex_str) == 6) {
            $color_val = hexdec($hex_str);
            return [
                'r' => 0xFF & ($color_val >> 0x10),
                'g' => 0xFF & ($color_val >> 0x8),
                'b' => 0xFF & $color_val
            ];
        } elseif (strlen($hex_str) == 3) {
            return [
                'r' => hexdec(str_repeat(substr($hex_str, 0, 1), 2)),
                'g' => hexdec(str_repeat(substr($hex_str, 1, 1), 2)),
                'b' => hexdec(str_repeat(substr($hex_str, 2, 1), 2))
            ];
        }

        return null;
    }
}