<?php
class captcha
{
var $session_key = null;
var $temp_dir = null;
var $width = 160;
var $height = 60;
var $jpg_quality = 15;


/**
* Constructor - Initializes Captcha class!
*
* @param string $session_key
* @param string $temp_dir
* @return captcha
*/
function captcha( $session_key, $temp_dir )
{
$this->session_key = $session_key;
$this->temp_dir = $temp_dir;
}


/**
* Generates Image file for captcha
*
* @param string $location
* @param string $char_seq
* @return unknown
*/
function _generate_image( $location, $char_seq )
{
$num_chars = strlen($char_seq);

$img = imagecreatetruecolor( $this->width, $this->height );
imagealphablending($img, 1);
imagecolortransparent( $img );

// generate background of randomly built ellipses
for ($i=1; $i<=200; $i++)
{
$r = round( rand( 0, 100 ) );
$g = round( rand( 0, 100 ) );
$b = round( rand( 0, 100 ) );
$color = imagecolorallocate( $img, $r, $g, $b );
imagefilledellipse( $img,round(rand(0,$this->width)), round(rand(0,$this->height)), round(rand(0,$this->width/16)), round(rand(0,$this->height/4)), $color );
}

$start_x = round($this->width / $num_chars);
$max_font_size = $start_x;
$start_x = round(0.5*$start_x);
$max_x_ofs = round($max_font_size*0.9);

// set each letter with random angle, size and color
for ($i=0;$i<=$num_chars;$i++)
{
$r = round( rand( 127, 255 ) );
$g = round( rand( 127, 255 ) );
$b = round( rand( 127, 255 ) );
$y_pos = ($this->height/2)+round( rand( 5, 20 ) );

$fontsize = round( rand( 18, $max_font_size) );
$color = imagecolorallocate( $img, $r, $g, $b);
$presign = round( rand( 0, 1 ) );
$angle = round( rand( 0, 25 ) );
if ($presign==true) $angle = -1*$angle;

ImageTTFText( $img, $fontsize, $angle, $start_x+$i*$max_x_ofs, $y_pos, $color, 'default.ttf', substr($char_seq,$i,1) );
}

// create image file
imagejpeg( $img, $location, $this->jpg_quality );
flush();
imagedestroy( $img );

return true;
}


/**
* Returns name of the new generated captcha image file
*
* @param unknown_type $num_chars
* @return unknown
*/
function get_pic( $num_chars=8 )
{
// define characters of which the captcha can consist
$alphabet = 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',
'1','2','3','4','5','6','7','8','9','0' );

$max = sizeof( $alphabet );

// generate random string
$captcha_str = '';
for ($i=1;$i<=$num_chars;$i++) // from 1..$num_chars
{
// choose randomly a character from alphabet and append it to string
$chosen = rand( 1, $max );
$captcha_str .= $alphabet[$chosen-1];
}

// generate a picture file that displays the random string
if ( $this->_generate_image( $this->temp_dir.'/'.'cap_'.md5( strtolower( $captcha_str )).'.jpg' , $captcha_str ) )
{
$fh = fopen( $this->temp_dir.'/'.'cap_'.$this->session_key.'.txt', "w" );
fputs( $fh, md5( strtolower( $captcha_str ) ) );
return( md5( strtolower( $captcha_str ) ) );
}
else
{
return false;
}
}

/**
* check hash of password against hash of searched characters
*
* @param string $char_seq
* @return boolean
*/
function verify( $char_seq )
{
$fh = fopen( $this->temp_dir.'/'.'cap_'.$this->session_key.'.txt', "r" );
$hash = fgets( $fh );

if (md5(strtolower($char_seq)) == $hash)
return true;
else
return false;
}
}


?>

<TABLE SUMMARY="Formular1" WIDTH="670" CELLPADDING="3" CELLSPACING="0" BORDER="0">
<TR VALIGN="top">
<TD WIDTH="100%" COLSPAN="2" CLASS="normal">
<IMG SRC="pics/transpix.gif" WIDTH="1" HEIGHT="1" VSPACE="1" HSPACE="155" ALT=""><BR>

<TABLE SUMMARY="Formular2" WIDTH="100%" CELLPADDING="10" CELLSPACING="0" BORDER="4" BGCOLOR="#EBFFC1">
<TR>
<TD>
<B>Meine Anfrage an die FN-Reitschule Conrad Beck.<A NAME="frm">*</A><BR></B><BR>
<?php
require_once( 'class.captcha.php' );

if (empty($_GET['session_code']))
{ $session_code = md5(round(rand(0,40000))); }
else
{ $session_code=$_GET['session_code']; }

$my_captcha = new captcha( $session_code, '__TEMP__/' );



$do = $_GET['do'];

if ($do == 'verify')
{
if ($my_captcha->verify( $_POST['password'] ) )
{
echo "Hier die Befehlszeile zu kontaktformbest.php";
exit;
}
}

$pic_url = $my_captcha->get_pic( 3 );

echo <<<FORM
<FORM NAME="Formular" METHOD="post" ACTION="$PHP_SELF?do=verify&session_code=$session_code?">
<FIELDSET>
<LEGEND><B>Absender</B></LEGEND>

...

<INPUT TYPE="submit" VALUE="Abschicken">

<INPUT TYPE="reset" VALUE="Verwerfen"><BR>
...
</TD></TR></TABLE>
</FIELDSET>

</FORM>
FORM;
?>
</TD></TR></TABLE>
</TD></TR></TABLE>

if ($name=='')

if ($_POST['name']=='')

$name = $_POST['name'];

<?
// Get gibts nicht, geh weg!
unset($_GET);

/*
Vars auswerten
*/
?>