有需要的朋友，參考下吧。
復制代碼 代碼如下:
<?php
/**
* 仿QQ驗證碼
*/
//Session保存路徑
$sessSavePath = dirname(__FILE__)."/../data/sessions/";
if(is_writeable($sessSavePath) && is_readable($sessSavePath)){ session_save_path($sessSavePath); }
session_start();
//獲取隨機字符
$rndstring = '';
for($i=0; $i<4; $i++) $rndstring .= chr(mt_rand(65,90));
$img_height=45; //先定義圖片的長、寬
$img_width=10;
//如果支持GD，則繪圖
if(function_exists("imagecreate"))
{
//Firefox部份情況會多次請求的問題，5秒內刷新頁面將不改變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);
//創建圖片，並設置背景色
$im = imagecreate(46,20);
ImageColorAllocate($im, 240,243,248);
//干擾線
$lineColor1 = ImageColorAllocate($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);
}
//輸出文字
$fontColor = ImageColorAllocate($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], $fontColor);
}
header("Pragma:no-cache"r"n");
header("Cache-Control:no-cache"r"n");
header("Expires:0"r"n");
//輸出特定類型的圖片格式，優先級為 gif -> jpg ->png
if(function_exists("imagepng"))
{
header("content-type:image/png"r"n");
imagepng($im);
}
else
{
header("content-type:image/jpeg"r"n");
imagejpeg($im);
}
ImageDestroy($im);
exit();
}
else
{
//不支持GD，只輸出字母 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();
}
?>
