function UpdateImage($pic='php.jpg',$wrate=2,$hrate=2){
/*
先判断图片的类型，决定下面要使用什么函数 如果是gif格式的使用imagecreatefromgif()[从 GIF 文件或 URL 新建一图像];
在本例中也可以对图片进行比例的缩放
*/
$imagemsg = getimagesize($pic);
$type_tmp = $imagemsg['mime'];
$width = $imagemsg[0];
$height = $imagemsg[1];
$type = substr($type_tmp,strpos($type_tmp,'/')+1);
if($type == 'jpeg') {
$fun = 'ImageCreateFromJPEG';
$funout = 'imagejpeg';
$Content_Type = 'Content-Type: image/jpeg';
} else if($type == 'gif') {
$fun = 'imagecreatefromgif';
$funout = 'imagegif';
$Content_Type = 'Content-Type: image/gif';
}
$src = $fun($pic);
$x = $width/$wrate; $y = $height/$hrate;
$dst = ImageCreateTrueColor($x,$y);
ImageCopyResampled($dst,$src,0,0,0,0,$x,$y,$width,$height);
header($Content_Type);
$funout($dst);
}
UpdateImage(); /**
* 一段可以保持图片不变形的函数
* 函数名称: resizePic
* 函数功能: 合理缩放图片
* 输入参数: $path ----------------- 图片路径
$maxwidth ------------- 最大宽度
$maxheight ------------ 最大高度
* 函数返回值: array
* 其它说明: 2004-8-22
*/
function resizePic($path,$maxwidth=120,$maxheight=120)
{
$info = array();
$pic_size = @GetImageSize($path['tmp_name']);
$imagewidth = $pic_size['0'];
$imageheight = $pic_size['1'];
if ($imagewidth > $maxwidth)
{
$imageprop = ($maxwidth*100)/$imagewidth;
$imagevsize = ($imageheight*$imageprop)/100 ;
$imagewidth = $maxwidth;
$imageheight = ceil($imagevsize);
}
if ($imageheight > $maxheight)
{
$imageprop = ($maxheight*100)/$imageheight;
$imagehsize = ($imagewidth*$imageprop)/100 ;
$imagewidth = ceil($imagehsize);
$imageheight = $maxheight;
}
$info['width'] = $imagewidth;
$info['height'] = $imageheight;
Return $info;
}

?>