<?php
/**
* This file is part of Aksara CMS, both framework and publishing
* platform.
*
* @author Aby Dahana <abydahana@gmail.com>
* @copyright (c) Aksara Laboratory <https://aksaracms.com>
* @license MIT License
*
* This source file is subject to the MIT license that is bundled
* with this source code in the LICENSE.txt file.
*
* When the signs come, those who don't believe at "that time"
* will have only two choices, commit suicide or become brutal.
*/
if (! function_exists('create_captcha')) {
/**
* Create CAPTCHA
*
* @param array|string $data Data for the CAPTCHA or word
* @param string $img_path Path to create the image in
* @param string $img_url URL to the CAPTCHA image folder
* @param string $font_path Server path to font
*/
function create_captcha(array|string $data = [], string $img_path = '', string $img_url = '', string $font_path = ''): array|bool
{
$defaults = [
'word' => '',
'img_path' => $img_path,
'img_url' => $img_url,
'font_path' => $font_path,
'img_width' => 150,
'img_height' => 35,
'font_size' => 16,
'expiration' => 7200,
'word_length' => 6,
'img_id' => 'captcha-' . uniqid(),
'pool' => '23456789abcdefghjkmnpqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ',
'colors' => [
'background' => [255, 255, 255],
'border' => [200, 200, 200],
'text' => [50, 50, 50],
'grid' => [235, 235, 235]
]
];
// Merge configuration
$config = is_array($data) ? array_merge($defaults, $data) : $defaults;
// Check for GD extension and basic requirements
if (! extension_loaded('gd') || empty($config['img_path']) || ! is_dir($config['img_path']) || ! is_writable($config['img_path'])) {
return false;
}
// -----------------------------------
// 1. Generate Word
// -----------------------------------
$word = $config['word'];
if (empty($word)) {
$word = '';
$pool_length = strlen($config['pool']);
for ($i = 0; $i < $config['word_length']; $i++) {
try {
$word .= $config['pool'][random_int(0, $pool_length - 1)];
} catch (\Throwable $e) {
$word .= $config['pool'][mt_rand(0, $pool_length - 1)];
}
}
}
// -----------------------------------
// 2. Image Creation (With Distortion)
// -----------------------------------
try {
$now = microtime(true);
$width = (int) $config['img_width'];
$height = (int) $config['img_height'];
// Temporary image for text before distortion
$im_tmp = imagecreatetruecolor($width, $height);
$im = imagecreatetruecolor($width, $height);
if (! $im_tmp instanceof \GdImage || ! $im instanceof \GdImage) {
return false;
}
// Assign colors
$colors = [];
$colors_tmp = [];
foreach ($config['colors'] as $key => $rgb) {
$colors[$key] = imagecolorallocate($im, $rgb[0], $rgb[1], $rgb[2]);
$colors_tmp[$key] = imagecolorallocate($im_tmp, $rgb[0], $rgb[1], $rgb[2]);
}
// Background for both
imagefilledrectangle($im_tmp, 0, 0, $width, $height, $colors_tmp['background']);
imagefilledrectangle($im, 0, 0, $width, $height, $colors['background']);
// -----------------------------------
// 3. Write Text to Temp Image
// -----------------------------------
$use_font = (! empty($config['font_path']) && file_exists($config['font_path']));
$x = 10;
$length = strlen($word);
for ($i = 0; $i < $length; $i++) {
// Random color for each character
$char_color = imagecolorallocate($im_tmp, mt_rand(0, 150), mt_rand(0, 150), mt_rand(0, 150));
if ($use_font) {
$angle = mt_rand(-15, 15);
$y = mt_rand((int) ($height / 1.4), $height - 5);
imagettftext($im_tmp, (int) $config['font_size'], $angle, (int) $x, (int) $y, $char_color, $config['font_path'], $word[$i]);
} else {
$y = mt_rand(2, (int) ($height / 4));
imagestring($im_tmp, 5, (int) $x, (int) $y, $word[$i], $char_color);
}
$x += ($width - 20) / $length;
}
// -----------------------------------
// 4. Apply Sinusoidal Distortion
// -----------------------------------
$freq = mt_rand(5, 8) / 100; // Frequency
$amp = mt_rand(3, 5); // Amplitude
$phase = mt_rand(0, 10); // Phase shift
for ($i = 0; $i < $width; $i++) {
$offset = (int) (sin($i * $freq + $phase) * $amp);
imagecopy($im, $im_tmp, $i, $offset, $i, 0, 1, $height);
}
// -----------------------------------
// 5. Draw Noise (Foreground - Balanced)
// -----------------------------------
// Draw grid OVER the text (less dense)
for ($i = 0; $i < $width; $i += 20) {
imageline($im, $i, 0, $i, $height, $colors['grid']);
}
for ($i = 0; $i < $height; $i += 20) {
imageline($im, 0, $i, $width, $i, $colors['grid']);
}
// Lighter crossing lines (only 2)
for ($i = 0; $i < 2; $i++) {
$line_color = imagecolorallocate($im, mt_rand(180, 220), mt_rand(180, 220), mt_rand(180, 220));
imageline($im, 0, mt_rand(0, $height), $width, mt_rand(0, $height), $line_color);
}
// Random arcs (only 2, lighter)
for ($i = 0; $i < 2; $i++) {
$arc_color = imagecolorallocate($im, mt_rand(180, 220), mt_rand(180, 220), mt_rand(180, 220));
imagearc($im, mt_rand(0, $width), mt_rand(0, $height), mt_rand(50, 150), mt_rand(30, 100), mt_rand(0, 360), mt_rand(0, 360), $arc_color);
}
// Random noise pixels (back to 50)
for ($i = 0; $i < 50; $i++) {
imagesetpixel($im, mt_rand(0, $width), mt_rand(0, $height), $colors['text']);
}
// Add Border
imagerectangle($im, 0, 0, $width - 1, $height - 1, $colors['border']);
// -----------------------------------
// 6. Output & Cleanup
// -----------------------------------
$img_filename = $now . '.png';
$img_url = rtrim($config['img_url'], '/') . '/';
if (! imagepng($im, $config['img_path'] . $img_filename)) {
return false;
}
imagedestroy($im);
imagedestroy($im_tmp);
return [
'word' => $word,
'time' => $now,
'image' => '<img id="' . $config['img_id'] . '" src="' . $img_url . $img_filename . '" style="width: ' . $width . 'px; height: ' . $height . 'px; border: 0;" alt="CAPTCHA" />',
'filename' => $img_filename
];
} catch (\Throwable $e) {
return false;
}
}
}
if (! function_exists('generate_captcha')) {
/**
* Generate CAPTCHA wrapper
*/
function generate_captcha(): array
{
$string = '23456789ABCDEFGHJKMNPQRSTUVWXYZ';
$length = 6;
$captcha = [];
if (is_writable(UPLOAD_PATH)) {
if (! is_dir(UPLOAD_PATH . DIRECTORY_SEPARATOR . 'captcha')) {
try {
mkdir(UPLOAD_PATH . DIRECTORY_SEPARATOR . 'captcha', 0755, true);
} catch (\Throwable $e) {
// Safe abstraction
}
}
if (is_dir(UPLOAD_PATH . DIRECTORY_SEPARATOR . 'captcha') && is_writable(UPLOAD_PATH . DIRECTORY_SEPARATOR . 'captcha')) {
// Try to use a smoother TTF font from vendor if available
$font_path = ROOTPATH . 'vendor' . DIRECTORY_SEPARATOR . 'mpdf' . DIRECTORY_SEPARATOR . 'mpdf' . DIRECTORY_SEPARATOR . 'ttfonts' . DIRECTORY_SEPARATOR . 'DejaVuSans.ttf';
$captcha = create_captcha([
'img_path' => UPLOAD_PATH . DIRECTORY_SEPARATOR . 'captcha' . DIRECTORY_SEPARATOR,
'img_url' => base_url(UPLOAD_PATH . '/captcha'),
'img_width' => 120,
'img_height' => 35,
'font_path' => (file_exists($font_path) ? $font_path : ''),
'font_size' => 14,
'expiration' => 3600,
'word_length' => $length,
'pool' => $string,
'colors' => [
'background' => [255, 255, 255],
'border' => [255, 255, 255],
'grid' => [0, 0, 0],
'text' => [0, 0, 0]
]
]);
}
}
if (! $captcha) {
$captcha = [
'word' => substr(str_shuffle(str_repeat($string, ceil($length / strlen($string)))), 1, $length),
'filename' => null
];
}
// Set captcha word into session, used to next validation
set_userdata([
'captcha' => $captcha['word'],
'captcha_file' => $captcha['filename']
]);
return [
'image' => ($captcha['filename'] ? base_url(UPLOAD_PATH . '/captcha/' . $captcha['filename']) : null),
'string' => (! $captcha['filename'] ? $captcha['word'] : null)
];
}
}
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