<?
session_start();

//Set these avriables as you wish
$fontsize = 20;
$numcharacters = 5;
$bgcolor = "AE0000";
$textcolor = "FFFFFF";
$num_interference_lines = 3;

//At least one of these MUST be true
$str_includes_numbers = true;
$str_includes_uppercase = true;
$str_includes_lowercase = false;

//Generate Captcha String
$_SESSION['captcha'] = RandString($numcharacters, $str_includes_numbers, $str_includes_uppercase, $str_includes_lowercase);

//Send a generated image to the browser
create_image($numcharacters, $fontsize, $bgcolor, $textcolor, $num_interference_lines);
exit();

function create_image($length, $fontsize, $bgcolor, $textcolor, $numlines)
{

    //Set the image width and height
	$trifont = 1.5 * $fontsize;
    $width = ($trifont * $length);
    $height = 3 * $fontsize;

    //Create the image resource 
    $image = imagecreate($width, $height);  

    //We are making colors
    $forecolor = imagecolorallocate($image, hexdec(substr($textcolor,0,2)), hexdec(substr($textcolor,2,2)), hexdec(substr($textcolor,4,2)));
    $backcolor = imagecolorallocate($image, hexdec(substr($bgcolor,0,2)), hexdec(substr($bgcolor,2,2)), hexdec(substr($bgcolor,4,2)));

    //Make the background backcolor 
    imagefill($image, 0, 0, $backcolor); 

    //Add randomly generated string in forecolor to the image
    //imagestring($image, 7, 30, 3, $pass, $forecolor); 

    //Tell the browser what kind of file will display 
    header("Content-Type: image/jpeg");
	
	//imageloadfont("chick.ttf");
	
	for($i = 0; $i < $length; $i++) {
		$source = imagecreate($trifont, $trifont);

		//We are making colors
		$forecolors = imagecolorallocate($source, hexdec(substr($textcolor,0,2)), hexdec(substr($textcolor,2,2)), hexdec(substr($textcolor,4,2)));
		$backcolors = imagecolorallocate($source, hexdec(substr($bgcolor,0,2)), hexdec(substr($bgcolor,2,2)), hexdec(substr($bgcolor,4,2)));

		imagefill($source, 0, 0, $backcolors); 
		
		//imagestring($source, 5, 3, 0, substr($_SESSION['captcha'], $i, 1), $forecolors); 
		
		
		imagettftext($source, $fontsize, 0, 0, 18, $forecolors, "Alpha Romanie G98.ttf", substr($_SESSION['captcha'], $i, 1));

        //Rotate Somehow
		switch(mt_rand(1,8)) {
            case 1:
				$source = imagerotate($source, -20, $backcolors);
                break;
            case 2:
				$source = imagerotate($source, 20, $backcolors);
                break;
            case 3:
				$source = imagerotate($source, -15, $backcolors);
                break;
            case 4:
				$source = imagerotate($source, 15, $backcolors);
                break;
            case 5:
				$source = imagerotate($source, -10, $backcolors);
                break;
            case 6:
				$source = imagerotate($source, 10, $backcolors);
                break;
            case 7:
				$source = imagerotate($source, -2, $backcolors);
                break;
            case 8:
				$source = imagerotate($source, 2, $backcolors);
                break;
		}
        //Set Location variables
		$loc_x = 5+($trifont*$i);
		$loc_y = $trifont/2 + mt_rand((-1 * $fontsize/10),($fontsize/10));
		//Set Size Variables
		$size_x = $trifont * (mt_rand(100, 110) / 100);
		$size_y = $trifont * (mt_rand(100, 110) / 100);
		
		imagecopymerge($image,$source,$loc_x,$loc_y,0,0,$size_x,$size_y,90);

		imagedestroy($source);
	}
	
    /*Throw in some lines to make it a little bit harder for any bots to break */
	imagesetstyle($image, array($forecolor, $forecolor, $forecolor, $forecolor, $forecolor, $forecolor, $forecolor, $forecolor, IMG_COLOR_TRANSPARENT, IMG_COLOR_TRANSPARENT, IMG_COLOR_TRANSPARENT, IMG_COLOR_TRANSPARENT, IMG_COLOR_TRANSPARENT, IMG_COLOR_TRANSPARENT, IMG_COLOR_TRANSPARENT, IMG_COLOR_TRANSPARENT));
    imagerectangle($image,0,0,$width-1,$height-1,$forecolor);
	//for($i = 1; $i < mt_rand(1,5); $i++) {
	for($i = 1; $i < (1 + $numlines); $i++) {
		$from_x = mt_rand(0, $width);
		$from_y = mt_rand(0, $height);
		$to_x = mt_rand(0, $width);
		$to_y = mt_rand(0, $height);
		imageline($image, $from_x, $from_y, $to_x, $to_y, IMG_COLOR_STYLED); 
	}
 
    //Output the newly created image in jpeg format 
    imagejpeg($image);
   
    //Free up resources
    imagedestroy($image);
}

function RandString($len, $num, $uc, $lc) {
    if (!$len || $len<1 || $len>100) {
        print "Error: \"Length\" out of range (1-100)<br>\n";
        return;
    }
    if (!$num && !$uc && !$lc) {
        print "Error: No character types specified<br>\n";
        return;
    }

    $s="";
    $i=0;
    do {
        switch(mt_rand(1,3)) {
            // get number - ASCII characters (0:48 through 9:57)
            case 1:
                if ($num==1) {
                    $s .= chr(mt_rand(48,57));
                    $i++;
                }
                break;

            // get uppercase letter - ASCII characters (a:65 through z:90)
            case 2:
                if ($uc==1) {
                    $s .= chr(mt_rand(65,90));
                    $i++;
                }
                break;

            // get lowercase letter - ASCII characters (A:97 through Z:122)
            case 3:
                if ($lc==1) {
                    $s .= chr(mt_rand(97,122));
                    $i++;
                }
                break;
        }
    } while ($i<$len);

    return $s;
}
?>