discuz x3.2 提取帖子第一张图片生成缩略图代码

<?php
require_once './source/class/class_core.php';
$discuz = & discuz_core::instance();
$discuz->init();
list($w,$h)=explode("x",$_G['gp_size']);
$m=0;
if($w==0&&$h==0){
        $m=5;
}elseif ($h==0){
        $m=3;
}elseif ($w==0){
        $m=4;
}
/*
$w=100;//宽度
$h=75;//高度
$m=0;//缩略图模式
        //mode=0为固定宽高，画质裁切不变形
        //mode=1为固定宽高，画质会拉伸变形
        //mode=2为可变宽高，宽高不超过指定大小
        //mode=3为固定宽度，高度随比例变化
*/

$nopic='./static/image/common/nophotosmall.gif';//缺省图片

$aid=intval($_G['gp_aid']);
$dir="data/aidpic/";
$subdir=$dir."/{$w}x{$h}x{$m}/";
$thumbfile=$subdir."/".$aid.".jpg";
if(file_exists($thumbfile)){
        header("location:{$thumbfile}");
        die();
}
$tableid=substr($aid,-1,1);
$attach=DB::fetch_first("SELECT a.tid,a.attachment,a.remote
FROM ".DB::table("forum_attachment_{$tableid}")." a
WHERE a.`tid` ='$aid'
AND a.`isimage`<>0
order by a.aid asc
limit 0,1");

if($attach){
        $attachurl=$attach['remote']?$_G['setting']['ftp']['attachurl']:$_G['setting']['attachurl'];
        $attachfile=$attachurl."/forum/".$attach['attachment'];
        if(!is_dir($dir)) @mkdir($dir);
        if(!is_dir($subdir)) @mkdir($subdir);
        dzthumb($attachfile,$thumbfile,$w,$h,$m);
        header("location:{$thumbfile}");
        die();
}else{
        header("location:$nopic");
        die();
}

function dzthumb($srcfile,$dstfile,$dstw,$dsth=0,$mode=0,$data=''){
        $data=$data==''?@GetImageSize($srcfile):$data;
        if(!$data) return false;
        if($data[2]==2) $im=@ImageCreateFromJPEG($srcfile);
        elseif ($data[2]==1) $im=@ImageCreateFromGIF($srcfile);
        elseif($data[2]==3) $im=@ImageCreateFromPNG($srcfile);
        list($img_w, $img_h) = $data;
        if($dsth==0) $mode=3;
        if($mode==0){
                $imgratio = $img_w / $img_h;
                $thumbratio = $dstw / $dsth;
                if($imgratio >= 1 && $imgratio >= $thumbratio || $imgratio < 1 && $imgratio > $thumbratio) {
                        $cuty = $img_h;
                        $cutx = $cuty * $thumbratio;
                } elseif($imgratio >= 1 && $imgratio <= $thumbratio || $imgratio < 1 && $imgratio < $thumbratio) {
                        $cutx = $img_w;
                        $cuty = $cutx / $thumbratio;
                }
                $cx = $cutx;
                $cy = $cuty;
        }elseif($mode==1){
                $cx = $img_w;
                $cy = $img_h;
        }elseif ($mode==2){
                $cx = $img_w;
                $cy = $img_h;
                $bit=$img_w/$img_h;
                if($dstw/$dsth>$bit){
                        $dstw=($img_w/$img_h)*$dsth;
                }else{
                        $dsth=($img_h/$img_w)*$dstw;
                }
        }
        elseif($mode==3){
                $cx = $img_w;
                $cy = $img_h;
                $dsth=$dstw * $img_h / $img_w;
        }
        elseif ($mode==4){
                $cx = $img_w;
                $cy = $img_h;
                $dstw=$dsth * $img_w / $img_h;
        }
        $ni=imagecreatetruecolor($dstw,$dsth);
        ImageCopyResampled($ni,$im,0,0,0,0,$dstw,$dsth, $cx, $cy);
        clearstatcache();
        if($data[2]==2) ImageJPEG($ni,$dstfile,100);
        elseif($data[2]==1) ImageGif($ni,$dstfile);
        elseif($data[2]==3) ImagePNG($ni,$dstfile);
        return true;
}

?>