Ciao a tutti,
Ho trovato questo CPTCHA free su un sito.
Questo è l’index
Codice PHP:
<?php session_start();
if(isset($_POST["captcha"]))
{
    if (isset($_SESSION["captcha"]) && $_SESSION["captcha"]==$_POST["captcha"])
    { header("Location: salva.php");}
} 
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-gb" lang="en-gb" >
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Captcha</title>
<script type="text/javascript">
function reloadCaptcha() {
now = new Date();
var capObj = document.getElementById('phoca-captcha');
if (capObj) {
capObj.src = capObj.src + (capObj.src.indexOf('?') > -1 ? '&' : '?') + Math.ceil(Math.random()*(now.getTime()));
}
}
</script>
<style type="text/css">
body{font-family:sans-serif;}
a img {border:0}
</style>

</head>
<body>
<form action="index.php" method="post" name="phoca-form" id="phoca-form">
<table border="0">
<tr>
<td width="5">Title: </td>
<td colspan="4"><input type="text" name="title" id="title" size="32" maxlength="200" style="border:1px solid #cccccc" width:"300px" value="<?php
if(isset($title)){ print "$title"; }
?>" /></td>
</tr>

<tr>
<td>Content: </td>
<td colspan="4"><textarea name="testo" cols="32" rows="10" id="testo" style="border:1px solid #cccccc" ><?php
if(isset($testo)){ print "$testo"; }
?></textarea>
</td>
</tr>

<tr>
<td>Image Verification: </td>

<td width="5" align="left">[img]image.php[/img]</td>
<td width="5" align="left"><input type="text" id="captcha" name="captcha" size="6" maxlength="6" style="border:1px solid #cccccc"/></td>

<td width="5" align="left">[img]./images/icon-reload.gif[/img]</td>
<td align="left"><small style="color:#fc0000;"></small></td>
</tr>
<tr>
<td></td>
<td colspan="4"><input type="submit" name="save" value="Submit" /> <input type="reset" name="reset" value="Reset" /></td>
</tr>
</table>
</form>
<hr />
</body>
</html>

Questa invece è la classe che viene richiamata

Codice PHP:

<?php
/*
 * @class Phoca Captcha
 * @copyright Copyright (C) Jan Pavelka [url]www.phoca.cz[/url]
 * @license [url]http://www.gnu.org/copyleft/gpl.html[/url] GNU/GPL
 */
class PhocaCaptcha
{
    function displayCaptcha()
    {
        session_start();
        #header("Expires: Sun, 1 Jan 2000 12:00:00 GMT"); 
        #header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT"); 
        #header("Cache-Control: no-store, no-cache, must-revalidate"); 
        #header("Cache-Control: post-check=0, pre-check=0", false);
        #header("Pragma: no-cache");

        $rand_char = PhocaCaptcha::generateRandomChar(6);
        $_SESSION['captcha'] = $rand_char;
        $rand_char_array = array (            $rand_char[0]."          ",
                                        "  ".$rand_char[1]."        "    ,
                                          "    ".$rand_char[2]."      "    ,
                                      "      ".$rand_char[3]."    "   ,
                                     "        ".$rand_char[4]."  "    ,
                                    "          ".$rand_char[5]);

        $image_name     = PhocaCaptcha::getRandomImage();
        $image             = @ImageCreateFromJPEG('images/'.$image_name);
 
        foreach ($rand_char_array as $key => $value)
        {
         $font_color     = PhocaCaptcha::getRandomFontColor();
         $position_x     = PhocaCaptcha::getRandomPositionX();
         $position_y     = PhocaCaptcha::getRandomPositionY();
         $font_size     = PhocaCaptcha::getRandomFontSize();
         
         ImageString($image, $font_size, $position_x, $position_y, $value, ImageColorAllocate ($image, $font_color[0], $font_color[1], $font_color[2]));
        }
        
        header ('Content-type: image/jpeg');
        ImageJPEG($image,NULL,100);
        ImageDestroy($image);
    }


    function generateRandomChar($string_length)
    {
        
        $digit = array(0,1,2,3,4,5,6,7,8,9);
        $lower = array('a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z');
        $upper = array('A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z');
        
        $char_group = array_merge ($digit, $lower, $upper);
        
        srand ((double) microtime() * 1000000);
        
        $random_string = '';
        
        for($ch=0;$ch<$string_length;$ch++)
        {
            $char_group_start    = 0;
            $char_group_end     = sizeof($char_group)-1;
            $random_char_group     = rand($char_group_start, $char_group_end);
            $random_string        .= $char_group[$random_char_group];
        }
        return $random_string;
    }

    function getRandomImage()
    {
        $rand     = mt_rand(1,6);
        $image     = '0'.$rand.'.jpg';
        return $image;
    }

    function getRandomPositionX()
    {
        $rand     = mt_rand(2,3);
        return $rand;
    }

    function getRandomPositionY()
    {
        $rand     = mt_rand(1,4);
        return $rand;
    }

    function getRandomFontSize()
    {
        $rand = mt_rand(4,5);
        return $rand;
    }

    function getRandomFontColor()
    {
        $rand = mt_rand(1,6);
        if ($rand == 1) {$font_color[0] = 10;     $font_color[1] = 0;     $font_color[2] = 0;}
        if ($rand == 2) {$font_color[0] = 0;     $font_color[1] = 0;     $font_color[2] = 153;}
        if ($rand == 3) {$font_color[0] = 0;     $font_color[1] = 102;     $font_color[2] = 0;}
        if ($rand == 4) {$font_color[0] = 102;     $font_color[1] = 51;     $font_color[2] = 0;}
        if ($rand == 5) {$font_color[0] = 163;     $font_color[1] = 0;     $font_color[2] = 0;}
        if ($rand == 6) {$font_color[0] = 0;     $font_color[1] = 82;     $font_color[2] = 163;}
        return $font_color;
    }
}
?>
Vorrei cambiare il font dei caratteri e la grandezza.

C’è chi mi sa dire come fare?

Grazie