复制代码 代码如下:

<?php
/**
 * 仿QQ验证码
*/
//Session保存路径
$sessSavePath = dirname(__FILE__).\"/../data/sessions/\";
if(is_writeable($sessSavePath) && is_readable($sessSavePath)){ session_save_path($sessSavePath); }
session_start();
//获取随机字符
$rndstring = \'\';
for($i=0; $i<4; $i++) $rndstring .= chr(mt_rand(65,90));
$img_height=45;    //先定义图片的长、宽
$img_width=10;
//如果支持GD，则绘图
if(function_exists(\"imagecreate\"))
{
 //Firefox部份情况会多次请求的问题，5秒内刷新页面将不改变session
 $ntime = time();
 if(empty($_SESSION[\'dd_ckstr_last\']) || empty($_SESSION[\'dd_ckstr\']) || ($ntime - $_SESSION[\'dd_ckstr_last\'] > 5))
 {
  $_SESSION[\'dd_ckstr\'] = strtolower($rndstring);
  $_SESSION[\'dd_ckstr_last\'] = $ntime;
 }
 $rndstring = $_SESSION[\'dd_ckstr\'];
 $rndcodelen = strlen($rndstring);
 //创建图片，并设置背景色
 $im = imagecreate(46,20);
 ImageColorAllocate($im, 240,243,248);
 //干扰线
 $lineColor1 = ImageColorAllocate($im, mt_rand(174,218),mt_rand(190,225),mt_rand(217,237));
 for($j=1;$j<=2;$j=$j+3)
 {
  imageline($im,0,$j+mt_rand(1,15),48,$j+mt_rand(1,15),$lineColor1);
 }
 //输出文字
 $fontColor = ImageColorAllocate($im, mt_rand(0,150),mt_rand(0,150),mt_rand(0,150));
 for($i=0;$i<$rndcodelen;$i++)
 {
  $bc = mt_rand(0,1);
  $rndstring[$i] = strtoupper($rndstring[$i]);
  imagestring($im,mt_rand(3,5),$i*$img_height/4+mt_rand(1,5),mt_rand(1,$img_width/2), $rndstring[$i], $fontColor);
 }
 header(\"Pragma:no-cache\"r\"n\");
 header(\"Cache-Control:no-cache\"r\"n\");
 header(\"Expires:0\"r\"n\");
 //输出特定类型的图片格式，优先级为 gif -> jpg ->png
 if(function_exists(\"imagepng\"))
 {
  header(\"content-type:image/png\"r\"n\");
  imagepng($im);
 }
 else
 {
  header(\"content-type:image/jpeg\"r\"n\");
  imagejpeg($im);
 }
 ImageDestroy($im);
 exit();
}
else
{
 //不支持GD，只输出字母 ABCD
 $_SESSION[\'dd_ckstr\'] = \"abcd\";
 $_SESSION[\'dd_ckstr_last\'] = \'\';
 header(\"content-type:image/png\"r\"n\");
 header(\"Pragma:no-cache\"r\"n\");
 header(\"Cache-Control:no-cache\"r\"n\");
 header(\"Expires:0\"r\"n\");
 $fp = fopen(\"data/vdcode.jpg\",\"r\");
 echo fread($fp,filesize(\"data/vdcode.jpg\"));
 fclose($fp);
 exit();
}
?>