php简单实用生成缩略图代码
本程序是根据用户上传图片后再把上传的图片按比例生成缩略图,程序实例代码如下:
- <?php
- $w?$resizewidth=$w:$resizewidth=400;// 生成图片的宽度
- $h?$resizeheight=$h:$resizeheight=400;// 生成图片的高度
- function resizeimage($im,$maxwidth,$maxheight,$name){
- $width = imagesx($im);
- $height = imagesy($im);
- if(($maxwidth && $width > $maxwidth) || ($maxheight && $height > $maxheight)){
- if($maxwidth && $width > $maxwidth){
- $widthratio = $maxwidth/$width;
- $resizewidth=true;
- }
- if($maxheight && $height > $maxheight){
- $heightratio = $maxheight/$height;
- $resizeheight=true;
- }
- if($resizewidth && $resizeheight){
- if($widthratio < $heightratio){
- $ratio = $widthratio;
- }else{
- $ratio = $heightratio;
- }
- }elseif($resizewidth){
- $ratio = $widthratio;
- }elseif($resizeheight){
- $ratio = $heightratio;
- }
- $newwidth = $width * $ratio;
- $newheight = $height * $ratio;
- if(function_exists("imagecopyresampled")){
- $newim = imagecreatetruecolor($newwidth, $newheight);
- imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
- }else{
- $newim = imagecreate($newwidth, $newheight);
- imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
- }
- imagejpeg ($newim,$name);
- imagedestroy ($newim);
- }else{
- imagejpeg ($im,$name);
- }
- }
- if($_files['uploadfile']['size']){
- if($_files['uploadfile']['type'] == "image/pjpeg"){
- $im = imagecreatefromjpeg($_files['uploadfile']['tmp_name']);
- }elseif($_files['uploadfile']['type'] == "image/x-png"){
- $im = imagecreatefrompng($_files['uploadfile']['tmp_name']);
- }elseif($_files['uploadfile']['type'] == "image/gif"){
- $im = imagecreatefromgif($_files['uploadfile']['tmp_name']);
- }
- if($im){
- if(file_exists('bbs.jpg')){
- unlink('bbs.jpg');
- }
- resizeimage($im,$resizewidth,$resizeheight,'bbs.jpg');
- imagedestroy ($im);
- }
- }
- //$uploadfile="www.phpfensi.com.jpg";
- ?>