PHP实现图片上传并压缩
本文实例讲解了PHP图片上传并压缩的实现方法，分享给大家供大家参考，具体内容如下
使用到三个文件
- connect.php：连接数据库
- test_upload.php：执行SQL语句
- upload_img.php：上传图片并压缩
三个文件代码如下：
连接数据库：connect.php
<?php
$db_host='';
$db_user='';
$db_psw='';
$db_name='';
$db_port='';
$sqlconn=newmysqli($db_host,$db_user,$db_psw,$db_name);
$q="setnamesutf8;";
$result=$sqlconn->query($q);
if(mysqli_connect_errno()){
printf("Connectfailed:%s\n",mysqli_connect_error());
exit();
}
?>
<?php
require("connect.php");
require("upload_img.php");
$real_img=$uploadfile;
$small_img=$uploadfile_resize;
$insert_sql="insertintoimg(real_img,small_img)values(?,?)";
$result=$sqlconn->prepare($insert_sql);
$result->bind_param("ss",$real_img,$small_img);
$result->execute();
?>
<?php
//设置文件保存目录
$uploaddir="upfiles/";
//设置允许上传文件的类型
$type=array("jpg","gif","bmp","jpeg","png");
//获取文件后缀名函数
functionfileext($filename)
{
returnsubstr(strrchr($filename,'.'),1);
}
//生成随机文件名函数
functionrandom($length)
{
$hash='CR-';
$chars='ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz';
$max=strlen($chars)-1;
mt_srand((double)microtime()*1000000);
for($i=0;$i<$length;$i++)
{
$hash.=$chars[mt_rand(0,$max)];
}
return$hash;
}
$a=strtolower(fileext($_FILES['filename']['name']));
//判断文件类型
if(!in_array(strtolower(fileext($_FILES['filename']['name'])),$type))
{
$text=implode(",",$type);
$ret_code=3;//文件类型错误
$page_result=$text;
$retArray=array('ret_code'=>$ret_code,'page_result'=>$page_result);
$retJson=json_encode($retArray);
echo$retJson;
return;
}
//生成目标文件的文件名
else
{
$filename=explode(".",$_FILES['filename']['name']);
do
{
$filename[0]=random(10);//设置随机数长度
$name=implode(".",$filename);
//$name1=$name.".Mcncc";
$uploadfile=$uploaddir.$name;
}
while(file_exists($uploadfile));
if(move_uploaded_file($_FILES['filename']['tmp_name'],$uploadfile))
{
if(is_uploaded_file($_FILES['filename']['tmp_name']))
{
$ret_code=1;//上传失败
}
else
{//上传成功
$ret_code=0;
}
}
$retArray=array('ret_code'=>$ret_code);
$retJson=json_encode($retArray);
echo$retJson;
}
//压缩图片
$uploaddir_resize="upfiles_resize/";
$uploadfile_resize=$uploaddir_resize.$name;
//$pic_width_max=120;
//$pic_height_max=90;
//以上与下面段注释可以联合使用，可以使图片根据计算出来的比例压缩
$file_type=$_FILES["filename"]['type'];
functionResizeImage($uploadfile,$maxwidth,$maxheight,$name)
{
//取得当前图片大小
$width=imagesx($uploadfile);
$height=imagesy($uploadfile);
$i=0.5;
//生成缩略图的大小
if(($width>$maxwidth)||($height>$maxheight))
{
/*
$widthratio=$maxwidth/$width;
$heightratio=$maxheight/$height;
if($widthratio<$heightratio)
{
$ratio=$widthratio;
}
else
{
$ratio=$heightratio;
}
$newwidth=$width*$ratio;
$newheight=$height*$ratio;
*/
$newwidth=$width*$i;
$newheight=$height*$i;
if(function_exists("imagecopyresampled"))
{
$uploaddir_resize=imagecreatetruecolor($newwidth,$newheight);
imagecopyresampled($uploaddir_resize,$uploadfile,0,0,0,0,$newwidth,$newheight,$width,$height);
}
else
{
$uploaddir_resize=imagecreate($newwidth,$newheight);
imagecopyresized($uploaddir_resize,$uploadfile,0,0,0,0,$newwidth,$newheight,$width,$height);
}
ImageJpeg($uploaddir_resize,$name);
ImageDestroy($uploaddir_resize);
}
else
{
ImageJpeg($uploadfile,$name);
}
}
if($_FILES["filename"]['size'])
{
if($file_type=="image/pjpeg"||$file_type=="image/jpg"|$file_type=="image/jpeg")
{
//$im=imagecreatefromjpeg($_FILES[$upload_input_name]['tmp_name']);
$im=imagecreatefromjpeg($uploadfile);
}
elseif($file_type=="image/x-png")
{
//$im=imagecreatefrompng($_FILES[$upload_input_name]['tmp_name']);
$im=imagecreatefromjpeg($uploadfile);
}
elseif($file_type=="image/gif")
{
//$im=imagecreatefromgif($_FILES[$upload_input_name]['tmp_name']);
$im=imagecreatefromjpeg($uploadfile);
}
else//默认jpg
{
$im=imagecreatefromjpeg($uploadfile);
}
if($im)
{
ResizeImage($im,$pic_width_max,$pic_height_max,$uploadfile_resize);
ImageDestroy($im);
}
}
?>
请按照现实情况更改connect.php，test_upload.php中对应的信息。
以上就是PHP实现图片上传并压缩的方法，希望对大家的学习php程序设计有所帮助