<?php
	// captcha code
	session_start();
	if (isset($_POST['len'])) :
		$len = $_POST['len'];
	else :
		$len = 6;
	endif;
	//$md5 = md5(microtime() * mktime());
	//$string = strtolower(substr($md5,0,$len));
	$string = '';
	$possible = '23456789bcdfghjkmnprstvwxyz';
	$i = 0;
	while ($i < $len) :
		$string .= substr($possible, mt_rand(0, strlen($possible)-1), 1);
		$i++;
	endwhile;
	$display_string = '';
	for ($i=0; $i< $len; $i++) :
		$display_string = $display_string.substr($string,$i,1).' ';
	endfor;
	//$captcha = imagecreatefrompng("./captcha.png");
	$captcha = imagecreatetruecolor(100,31);
	$font_color = imagecolorallocate($captcha,211,205,214);
	$line_color = imagecolorallocate($captcha,211,205,214);
	$bg = imagecolorallocate($captcha,95,92,93);
	imagefill($captcha, 0, 0, $bg);
	//for ($i=1; $i<= intval($len * 1.5); $i++) :
	imagesetthickness ($captcha,1);
	for ($i=0; $i< 100; $i = $i + 25) :
		$x1 = rand($i,$i + 10);
		$x2 = rand($x1-20,$x1+20);
		$y1 = rand(0,31);
		$y2 = rand(0,31);
		imageline($captcha,$x1,3,$x2,28,$line_color);
	endfor;
	//imageline($captcha,40,0,64,29,$line_color);
	imagestring($captcha, 4, 5, 5, $display_string, $font_color);
	$_SESSION['captcha_key'] = md5($string);
	header("Content-type: image/png");
	imagepng($captcha);
	// end captcha code
?>