Google reCAPTCHA Integration with PHP<\/a> tutorial earlier. But, if you want to create a custom PHP library for Captcha verification, this step-by-step guide helps you a lot.<\/p>\nYou can build custom CAPTCHA library to generate Captcha image and verify Captcha code using PHP. In this tutorial, we will show you how to create CAPTCHA image<\/b> and integrate Captcha verification functionality with PHP custom library.<\/p>\n
Before getting started take a look at the file structure of the Simple PHP Captcha<\/b> script.<\/p>\nphp_captcha\/<\/span>\r\n\u251c\u2500\u2500 index.php\r\n\u251c\u2500\u2500 get_captcha.php\r\n\u251c\u2500\u2500 Captcha.class.php\r\n\u251c\u2500\u2500 fonts\/<\/span>\r\n| \u2514\u2500\u2500 monofont.ttf\r\n\u251c\u2500\u2500 css\/<\/span>\r\n \u2514\u2500\u2500 style.css\r\n<\/pre>\nPHP Captcha Library (Captcha.class.php)<\/h2>\n
This Captcha class is a custom library that is used to generate images with CAPTCHA code using PHP.<\/p>\n
\n- The
createCaptcha()<\/code> function generates a random alphanumeric code and creates an image using the PHP GD library.<\/li>\n- The Captcha code is stored in $_SESSION for further verification.<\/li>\n
- Various configuration options are defined to customize the Captcha image with PHP.<\/li>\n<\/ul>\n
<?php
<\/span>class <\/span>Captcha
<\/span>{
<\/span>\/\/ Configuration Options
<\/span>var <\/span>$word <\/span>= <\/span>'0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'<\/span>;
var <\/span>$length <\/span>= <\/span>5<\/span>;
var <\/span>$img_width <\/span>= <\/span>160<\/span>;
var <\/span>$img_height <\/span>= <\/span>50<\/span>;
var <\/span>$font_path <\/span>= <\/span>''<\/span>;
var <\/span>$font_size <\/span>= <\/span>25<\/span>;
var <\/span>$expiration <\/span>= <\/span>7200<\/span>;
var <\/span>$bg_color <\/span>= <\/span>'#ffffff'<\/span>;
var <\/span>$border_color <\/span>= <\/span>'#996666'<\/span>;
var <\/span>$text_color <\/span>= <\/span>'#cc9999'<\/span>;
var <\/span>$grid_color <\/span>= <\/span>'#ffb6b6'<\/span>;
var <\/span>$shadow_color <\/span>= <\/span>'#fff0f0'<\/span>;
public function <\/span>__construct<\/span>(<\/span>$config <\/span>= array()){
<\/span>ob_start<\/span>();
<\/span>session_start<\/span>();
if (<\/span>count<\/span>(<\/span>$config<\/span>) > <\/span>0<\/span>){
foreach (<\/span>$config <\/span>as <\/span>$key <\/span>=> <\/span>$val<\/span>){
if (isset(<\/span>$this<\/span>-><\/span>$key<\/span>)){
<\/span>$method <\/span>= <\/span>'set_'<\/span>.<\/span>$key<\/span>;
if (<\/span>method_exists<\/span>(<\/span>$this<\/span>, <\/span>$method<\/span>)){
<\/span>$this<\/span>-><\/span>$method<\/span>(<\/span>$val<\/span>);
}else{
<\/span>$this<\/span>-><\/span>$key <\/span>= <\/span>$val<\/span>;
}
}
}
}
if ( ! <\/span>extension_loaded<\/span>(<\/span>'gd'<\/span>)){
return <\/span>FALSE<\/span>;
}
}
public function <\/span>createCaptcha<\/span>(){
<\/span>$str <\/span>= <\/span>''<\/span>;
for (<\/span>$i <\/span>= <\/span>0<\/span>; <\/span>$i <\/span>< <\/span>$this<\/span>-><\/span>length<\/span>; <\/span>$i<\/span>++){
<\/span>$str <\/span>.= <\/span>substr<\/span>(<\/span>$this<\/span>-><\/span>word<\/span>, <\/span>mt_rand<\/span>(<\/span>0<\/span>, <\/span>strlen<\/span>(<\/span>$this<\/span>-><\/span>word<\/span>) -<\/span>1<\/span>), <\/span>1<\/span>);
}
<\/span>$word <\/span>= <\/span>$str<\/span>;
<\/span>\/* Determine angle and position *\/
<\/span>$length <\/span>= <\/span>strlen<\/span>(<\/span>$word<\/span>);
<\/span>$angle <\/span>= (<\/span>$length <\/span>>= <\/span>6<\/span>) ? <\/span>rand<\/span>(-(<\/span>$length<\/span>-<\/span>6<\/span>), (<\/span>$length<\/span>-<\/span>6<\/span>)) : <\/span>0<\/span>;
<\/span>$x_axis <\/span>= <\/span>rand<\/span>(<\/span>6<\/span>, (<\/span>360<\/span>\/<\/span>$length<\/span>)-<\/span>16<\/span>);
<\/span>$y_axis <\/span>= (<\/span>$angle <\/span>>= <\/span>0 <\/span>) ? <\/span>rand<\/span>(<\/span>$this<\/span>-><\/span>img_height<\/span>, <\/span>$this<\/span>-><\/span>img_width<\/span>) : <\/span>rand<\/span>(<\/span>6<\/span>, <\/span>$this<\/span>-><\/span>img_height<\/span>);
<\/span>\/* Create image *\/
<\/span>if (<\/span>function_exists<\/span>(<\/span>'imagecreatetruecolor'<\/span>)){
<\/span>$im <\/span>= <\/span>imagecreatetruecolor<\/span>(<\/span>$this<\/span>-><\/span>img_width<\/span>, <\/span>$this<\/span>-><\/span>img_height<\/span>);
}else{
<\/span>$im <\/span>= <\/span>imagecreate<\/span>(<\/span>$this<\/span>-><\/span>img_width<\/span>, <\/span>$this<\/span>-><\/span>