QQ空间的“神奇”图片

<?php

error_reporting(0);

ob_start();

header('Content-Type: image/png');

define('IMG_NO', "no.png"); #刚开始显示的提示信息

define('IMG_BACKGROUND', "background.png");

define('IMG_WIDTH', 400);

define('IMG_HEIGHT', 128);

define('FONT_NAME', "AdobeHeitiStd-Regular.otf"); #字体文件名

define('CACHE_PATH', rtrim(realpath("./cache"), '/').'/'); #缓存目录

define('CACHE_EXPIRE', 60*60); #缓存时间，单位秒

#(!is_dir(CACHE_PATH) && is_writable(CACHE_PATH)) || die;

/*

$remote: 远程URL

$local: 本地缓存路径

$expire: 过期时间。为-1时，永久不更新缓存

*/

function load_from_cache($remote, $local, $expire = CACHE_EXPIRE, $as_path = false) {

#过滤潜在的危险字符

$local = preg_replace("/[.\/\\\?\*\'\"\|\:\<\>]/", "_", $local);

$cache = CACHE_PATH.$local;

#查找缓存

if(file_exists($cache) && ($expire = -1 || filemtime($cache) - time() < $expire))

return $as_path ? $cache : file_get_contents($cache);

#文件不存在或缓存过期，重新下载

$content = file_get_contents($remote);

file_put_contents($cache, $content);

return $as_path ? $cache : $content;

}

/*

返回客户端信息。

*/

function client_info() {

$url = "http://ip.taobao.com/service/getIpInfo.php?ip=";

$ip = ($_SERVER["HTTP_VIA"] && $_SERVER["HTTP_X_FORWARDED_FOR"] ?

$_SERVER["HTTP_X_FORWARDED_FOR"] : $_SERVER["REMOTE_ADDR"]);

$info = explode('"', load_from_cache($url.$ip, $ip, -1));

$string = $info[7].$info[23].$info[31].$info[47];

return json_decode('"'.$string.'"');

}

$referer = $_SERVER['HTTP_REFERER'];

#$referer = "http://user.qzone.qq.com/123456789/infocenter";

$pattern = "/http:\/\/user.qzone.qq.com\/(\d+)\/infocenter/";

if(preg_match($pattern, $referer, $matches)) {

#获取QQ号码

$uin = $matches[1];

$info = explode('"', load_from_cache(

"http://base.qzone.qq.com/fcg-bin/cgi_get_portrait.fcg?uins=".$uin, $uin));

$avatar = $info[3];

$nickname = iconv("GBK", "UTF-8//IGNORE", $info[5]);

$client = client_info();

#重点来了，生成图片

try{

$im = imagecreatefrompng(IMG_BACKGROUND);

#绘制头像

$avatar_file = load_from_cache($avatar, $uin.".jpg", 60*60*24, true);

$im_avatar = imagecreatefromjpeg($avatar_file);

imagecopymerge($im, $im_avatar, 14, 14, 0, 0, 100, 100, 100);

imagedestroy($im_avatar);

#绘制文字

$blue = imagecolorallocate($im, 0, 0x99, 0xFF);

$white = imagecolorallocate($im, 0xFF, 0xFF, 0xFF);

$texts = array(

array(12, 148, 40, $white, $uin),

array(18, 125, 70, $blue, $nickname),

array(16, 125, 100, $blue, $client)

);

foreach($texts as $key=>$value) {

imagettftext($im, $value[0], 0, $value[1], $value[2], $value[3], FONT_NAME,

mb_convert_encoding($value[4], "html-entities", "utf-8")); #解决乱码问题

}

imagepng($im);

imagedestroy($im);

header("Content-Length: ".ob_get_length());

ob_end_flush();

} catch (Exception $e) {

#die($e->getMessage());

$error = true;

}

} else {

$error = true;

}

if($error){

header('Content-Length: '.filesize(IMG_NO));

echo file_get_contents(IMG_NO);

}

这个估计理解起来有难度：

简单来说