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<?php
session_start();
$_SESSION = array();
include("simple-php-captcha.php");
$_SESSION['captcha'] = simple_php_captcha();
?>
<!DOCTYPE html>
<html>
<head>
<title>Example &raquo; A simple PHP CAPTCHA script</title>
<style type="text/css">
pre {
border: solid 1px #bbb;
padding: 10px;
margin: 2em;
}
img {
border: solid 1px #ccc;
margin: 0 2em;
}
</style>
</head>
<body>
<h1>
CAPTCHA Example
</h1>
<h2>Usage</h2>
<p>
The following code will prepare a CAPTCHA image and keep the code in a session
variable for later use:
</p>
<pre>
&lt;?php
session_start();
include("simple-php-captcha.php");
$_SESSION['captcha'] = simple_php_captcha();
?&gt;
</pre>
<p>
After the call to <code>simple_php_captcha()</code> above,
<code>$_SESSION['captcha']</code> will be something like this:
</p>
<pre>
<?php
print_r($_SESSION['captcha']);
?>
</pre>
<p>
To display the CAPTCHA image, create an HTML <code>&lt;img&gt;</code> using
<code>$_SESSION['captcha']['image_src']</code> as the <code>src</code> attribute:
</p>
<p>
<?php
echo '<img src="' . $_SESSION['captcha']['image_src'] . '" alt="CAPTCHA code">';
?>
</p>
<p>
To verify the CAPTCHA value on the next page load (or in an AJAX request), test
against <code>$_SESSION['captcha']['code']</code>. You can use
<code>strtolower()</code> or <code>strtoupper()</code> to perform a
case-insensitive match.
</p>
<h2>Configuration</h2>
<p>
Configuration is easy and all values are optional. To specify one or more options,
do this:
</p>
<pre>
&lt;?php
$_SESSION['captcha'] = simple_php_captcha( array(
'min_length' => 5,
'max_length' => 5,
'backgrounds' => array(image.png', ...),
'fonts' => array('font.ttf', ...),
'characters' => 'ABCDEFGHJKLMNPRSTUVWXYZabcdefghjkmnprstuvwxyz23456789',
'min_font_size' => 28,
'max_font_size' => 28,
'color' => '#666',
'angle_min' => 0,
'angle_max' => 10,
'shadow' => true,
'shadow_color' => '#fff',
'shadow_offset_x' => -1,
'shadow_offset_y' => 1
));
&gt;
</pre>
<h2>Notes</h2>
<ul>
<li>
<strong>Important!</strong> Make sure you call <code>session_start()</code> before
calling the <code>simple_php_captcha()</code> function
</li>
<li>
Requires PHP GD2 library
</li>
<li>
Backgound images must be in PNG format
</li>
<li>
Fonts must be either TTF or OTF
</li>
<li>
Backgrounds and fonts must be specified using their full paths (tip: use
<code>$_SERVER['DOCUMENT_ROOT'] . '/' . [path-to-file]</code>)
</li>
<li>
Angles should not exceed approximately 15 degrees, as the text will sometimes
appear outside of the viewable area
</li>
<li>
Creates a function called <code>simple_php_captcha()</code> in the global namespace
</li>
<li>
Uses the <code>$_SESSION['simple-php-captcha']</code> session variable
</li>
</ul>
</body>
</html>
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