<?
session_start();

$passlen = 4;
$height = 40;
$width = 192;

$gradient_red = 99;
$gradient_green = 175;
$gradient_blue = 255;

// Create the image
$im = imageCreateTrueColor($width, $height);

// Create some colors
$white = imagecolorallocate($im, 255, 255, 255);
$grey = imagecolorallocate($im, 128, 128, 128);
$lightgrey = imagecolorallocate($im, 170, 170, 170);
$lightestgrey = imagecolorallocate($im, 204, 204, 204);
$black = imagecolorallocate($im, 0, 0, 0);

imagefilledrectangle($im, 0, 0, $width, $height, $white);


$possiblechars = "ABCDEFGHJKLMNPQRSTWXYZbcdefghjkmnprstwxyz2345678";
$noisepossiblechars = "!@#$%^&*()_+=-<>?,./\|{}[]':;~`ABCDEFGHJKLMNPQRSTWXYZabcdefghjkmnpqrstwxyz23456789";
$code = "";

// generate code random letters
for($i = 0; $i<$passlen; $i++)
{
	$code = $code .
	substr($possiblechars,rand(0,strlen($possiblechars)-1),1);
}

// generate noise
for($i = 0; $i<($passlen*2); $i++)
{
	$noise = $noise .
	substr($noisepossiblechars,rand(0,strlen($noisepossiblechars)-1),1);
}

// generate more noise
for($i = 0; $i<($passlen*2); $i++)
{
	$noise2 = $noise2 .
	substr($noisepossiblechars,rand(0,strlen($noisepossiblechars)-1),1);
}

// lowercase > hash > store in session-variable
$_SESSION['code'] = strtolower($code);

//$image = imageCreateTrueColor($width, $height);

// make a gradient
for ($i = 0; $i < $width ; $i++)
{
$j = ($i+$gradient_red)*180/($width+$gradient_red)+75;
$k = ($i+$gradient_green)*180/($width+$gradient_green)+75;
$l = ($i+$gradient_blue)*180/($width+$gradient_blue)+75;
//$color = imagecolorallocate($image, $i*180/$width+75,$i*180/$width+75, $i*180/$width+75);
 
$color = imagecolorallocate($im, $j, $k, $l);
imageline($im, $i, 0, $i, $height, $color);
}


// print out noise
for($i=0; $i<$passlen; $i++)
{
  	$font = rand(3,5);
  	imagestring($im, $font, $width/$passlen*$i+rand(4,30),
	$height/rand(1,8)-rand(imagefontheight($font)/rand(1,8), imagefontheight(rand(1,5))),
	substr($noise,$i,1), $lightgrey);

	
    $ttfont = '/fonts/captcha3.ttf';
	$size = rand(8,21);
    $angle = rand(-30,30);
	$text_box = rand($size,$size+24);
    $text_separation = $width/$passlen*$i+rand(1,15);
    imagettftext($im, $size, $angle, $text_separation ,$text_box, $lightgrey, $ttfont, substr($noise,$i,1));
}

// print out noise2
for($i=0; $i<$passlen; $i++)
{
    $ttfont = '/fonts/captcha.ttf';
	$size = rand(8,21);
    $angle = rand(-30,30);
	$text_box = rand($size,$size+24);
    $text_separation = $width/$passlen*$i+rand(3,20);
    imagettftext($im, $size, $angle, $text_separation ,$text_box, $lightestgrey, $ttfont, substr($noise2,$i,1));
}

// print out the letters
for($i=0; $i<$passlen; $i++)
{
    $ttfont = '/fonts/captcha2.ttf';
	$size = rand(14,21);
    $angle = rand(-30,30);
	$text_box = rand($size,$size+12);
    $text_separation = $width/$passlen*$i+rand(4,7);
	
//  	imagestring($im, $font, $width/$passlen*$i+rand(4,7),
//	$height/2-rand(imagefontheight($font)/2, imagefontheight($font)),
//	substr($code,$i,1), $textcolor);
   
   imagettftext($im, $size, $angle, $text_separation+1 ,$text_box+1, $grey, $ttfont, substr($code,$i,1));
   imagettftext($im, $size, $angle, $text_separation ,$text_box, $black, $ttfont, substr($code,$i,1));
}

// draw border
$bordercolor = imagecolorallocate($im, 171, 173, 179);
imagerectangle($im,0,0,$width-1,$height-1,$bordercolor);

// fix headers to avoid caching
header("Expires: Wed, 1 Jan 1997 00:00:00 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");

header('Content-type: image/gif'); // set content-type

// Using imagepng() results in clearer text compared with imagejpeg() or imageGIF()

// output the image
imageGIF($im);
imagedestroy($im);
?>