啥也不说，直接上代码，大家可以自行添加增加水印功能：
代码如下:
<?php
/**
*
* @author zhao jinhan
* @date 2014年1月13日11:54:30
* @email xb_zjh@126.com
*
*/
header('Content-type:text/html; charset=utf-8');
//定义缩略图的宽高
define('THUMB_WIDTH',300);
define('THUMB_HEIGHT',300);
/**
* 重新生成上传的文件名
* @return string
* @author zhao jinhan
*
*/
function _file_type($filetype = null){
switch($filetype)
{
case "image/jpeg":
$fileextname = "jpg";
break;
case "image/gif":
$fileextname = "gif";
break;
case "image/png":
$fileextname = "png";
break;
default:
$fileextname = false;
break;
}
return $fileextname?date('YmdHis',time()).'.'.$fileextname:false;
}
/**
*
* @param string $filename
* @param string $width
* @param string $height
* @param string $quality
* @param string $savepath
* @return boolean
*/
function _make_thumb($filename='', $width=THUMB_WIDTH, $height=THUMB_HEIGHT, $savepath='./upload'){
if(file_exists($filename)){
//上传图片的尺寸
$imagesize=getimagesize($filename);
$imagewidth=$imagesize[0];
$imageheight=$imagesize[1];
$mime = $imagesize['mime'];
//宽高比例
$ratio = $imagewidth/$imageheight;
//新建一个背景图片
$bgimg = imagecreatetruecolor($width, $height);
$white = imagecolorallocate($bgimg, 255, 255, 255);
//填充背景色为白色
imagefill($bgimg,0,0,$white);
if($mime == 'image/gif'){
$im = @imagecreatefromgif($filename); /* Attempt to open */
$outfun = 'imagegif';
}elseif($mime == 'image/png'){
$im = @imagecreatefrompng($filename); /* Attempt to open */
$outfun = 'imagepng';
}else{
$im = @imagecreatefromjpeg($filename); /* Attempt to open */
$outfun = 'imagejpeg';
}
if($ratio > 1){
//宽度较大
if($imagewidth > $width){
//缩放图片到背景图片上
$new_width = $width;
$new_height = ($width*$imageheight)/$imagewidth;
$bg_y = ceil(abs(($height-$new_height)/2));
imagecopyresampled($bgimg, $im, 0, $bg_y, 0, 0, $new_width, $new_height, $imagewidth, $imageheight);
}else{
//复制图片到背景图片上
$copy = true;
}
}else{
//高度较大
if($imageheight > $height){
//缩放图片
$new_height = $height;
$new_width = ($height*$imagewidth)/$imageheight;
$bg_x = ceil(($width-$new_width)/2);
imagecopyresampled($bgimg, $im, $bg_x, 0, 0, 0, $new_width, $new_height, $imagewidth, $imageheight);
}else{
//复制图片到背景图片上
$copy = true;
}
}
if($copy){
//复制图片到背景图片上
$bg_x = ceil(($width-$imagewidth)/2);
$bg_y = ceil(($height-$imageheight)/2);
imagecopy($bgimg, $im, $bg_x, $bg_y, 0, 0, $imagewidth, $imageheight);
}
$ext = _file_type($mime);
$outfun($bgimg, $savepath.'/'.$ext);
