PHP实现图片上传并压缩

发布:smiling　来源: PHP粉丝网　添加日期：2021-06-30 21:42:16　浏览: 评论：0　

这篇文章主要介绍了PHP实现图片上传并压缩的相关资料，上传图片然后按照比例缩略图，感兴趣的小伙伴们可以参考一下，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 = '';

$sqlconn=new mysqli($db_host,$db_user,$db_psw,$db_name);

$q="set names utf8;";

$result=$sqlconn->query($q);

if (mysqli_connect_errno()) {

printf("Connect failed: %s\n", mysqli_connect_error());

exit();

}

?>

执行SQL语句：test_upload.php

<?php

require ("connect.php");

require ("upload_img.php");

$real_img=$uploadfile;

$small_img=$uploadfile_resize;

$insert_sql = "insert into img (real_img,small_img) values (?,?)";

$result = $sqlconn -> prepare($insert_sql);

$result -> bind_param("ss", $real_img,$small_img);

$result -> execute();

?>

上传图片并压缩：upload_img.php

<?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

function fileext($filename)

{

return substr(strrchr($filename, '.'), 1);

}

//生成随机文件名函数

function random($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'];

function ResizeImage($uploadfile,$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);

}

}

?>