php功能-php制作缩略图

项目中偶然要做一个缩略图，在这里和大家分享一下(已测试),简单设置下

1.设置变量FILENAME=缩略图存放目录和文件名前缀

2MOVENAME=设置原图要存放的目录和文件名前缀

3.RESIZEWIDTH=设置生成图片的宽度

4.RESIZEHEIGHT=设置生成图片的高度

代码如下:

<?
$timename = time().rand(111,999);
$FILENAME='thumbnails/thumb_'.$timename;   //1缩略图存放目录和上传文件名
$MOVENAME='public/upload/'.$timename;        //2设置原图存放位置和文件名

// 3生成图片的宽度
$RESIZEWIDTH=200;

//4 生成图片的高度
$RESIZEHEIGHT=300;

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,$name . ".jpg");  //生成缩略图
ImageDestroy ($newim);
}else{
ImageJpeg ($im,$name . ".jpg");     ////生成缩略图
}
}

if($_FILES['image']['size']){

if($_FILES['image']['type'] == "image/pjpeg" || $_FILES['image']['type'] == "image/jpeg"){
$im = imagecreatefromjpeg($_FILES['image']['tmp_name']);

}elseif($_FILES['image']['type'] == "image/x-png" || $_FILES['image']['type'] == "image/png"){
$im = imagecreatefrompng($_FILES['image']['tmp_name']);

}elseif($_FILES['image']['type'] == "image/gif"){
$im = imagecreatefromgif($_FILES['image']['tmp_name']);

}
if($im){
if(file_exists("$FILENAME.jpg")){
unlink("$FILENAME.jpg");
}

ResizeImage($im,$RESIZEWIDTH,$RESIZEHEIGHT,$FILENAME);
$file_name = explode(".",$_FILES['image']['name']); //切割获取文件后缀

move_uploaded_file($_FILES['image']['tmp_name'],$MOVENAME.'.'. $file_name[1] );    //移动原图片到文件夹
ImageDestroy ($im);
}
}

?>
<img src="<? echo  $FILENAME.'.jpg'; ?>"><br><br> <!--浏览器显示缩略图-->

<form enctype="multipart/form-data" method="post">
<br>
<input type="file" name="image" size="50" value="浏览"><p>
<input type="submit" value="上传图片">
</form>

</body>
</html>