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PHP实现图片压缩的两则实例_php技巧

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May 16, 2016 pm 08:39 PM

php压缩图片

本文介绍了PHP实现图片压缩的两种方法，读者可以根据具体应用参考或加以改进，以适应自身应用需求！废话不多说，主要代码部分如下：

实例1：

<&#63;php 
/** 
* desription 压缩图片 
* @param sting $imgsrc 图片路径 
* @param string $imgdst 压缩后保存路径 
*/
function image_png_size_add($imgsrc,$imgdst){ 
  list($width,$height,$type)=getimagesize($imgsrc); 
  $new_width = ($width>600&#63;600:$width)*0.9; 
  $new_height =($height>600&#63;600:$height)*0.9; 
  switch($type){ 
    case 1: 
      $giftype=check_gifcartoon($imgsrc); 
      if($giftype){ 
        header('Content-Type:image/gif'); 
        $image_wp=imagecreatetruecolor($new_width, $new_height); 
        $image = imagecreatefromgif($imgsrc); 
        imagecopyresampled($image_wp, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height); 
        imagejpeg($image_wp, $imgdst,75); 
        imagedestroy($image_wp); 
      } 
      break; 
    case 2: 
      header('Content-Type:image/jpeg'); 
      $image_wp=imagecreatetruecolor($new_width, $new_height); 
      $image = imagecreatefromjpeg($imgsrc); 
      imagecopyresampled($image_wp, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height); 
      imagejpeg($image_wp, $imgdst,75); 
      imagedestroy($image_wp); 
      break; 
    case 3: 
      header('Content-Type:image/png'); 
      $image_wp=imagecreatetruecolor($new_width, $new_height); 
      $image = imagecreatefrompng($imgsrc); 
      imagecopyresampled($image_wp, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height); 
      imagejpeg($image_wp, $imgdst,75); 
      imagedestroy($image_wp); 
      break; 
  } 
} 
/** 
* desription 判断是否gif动画 
* @param sting $image_file图片路径 
* @return boolean t 是 f 否 
*/
function check_gifcartoon($image_file){ 
  $fp = fopen($image_file,'rb'); 
  $image_head = fread($fp,1024); 
  fclose($fp); 
  return preg_match("/".chr(0x21).chr(0xff).chr(0x0b).'NETSCAPE2.0'."/",$image_head)&#63;false:true; 
} 
&#63;>

实例2：

<&#63;php
/*
----------------------------------------------------------------------
函数:调整图片尺寸或生成缩略图
返回:True/False
参数:
  $Image  需要调整的图片(含路径)
  $Dw=450  调整时最大宽度;缩略图时的绝对宽度
  $Dh=450  调整时最大高度;缩略图时的绝对高度
  $Type=1  1,调整尺寸; 2,生成缩略图
$path='img/';//路径
$phtypes=array(
  'img/gif',
  'img/jpg',
  'img/jpeg',
  'img/bmp',
  'img/pjpeg',
  'img/x-png'
);
Function Img($Image,$Dw=450,$Dh=450,$Type=1){
  IF(!File_Exists($Image)){
  Return False;
  }
  //如果需要生成缩略图,则将原图拷贝一下重新给$Image赋值
  IF($Type!=1){
  Copy($Image,Str_Replace(".","_x.",$Image));
  $Image=Str_Replace(".","_x.",$Image);
  }
  //取得文件的类型,根据不同的类型建立不同的对象
  $ImgInfo=GetImageSize($Image);
  Switch($ImgInfo[2]){
  Case 1:
  $Img = @ImageCreateFromGIF($Image);
  Break;
  Case 2:
  $Img = @ImageCreateFromJPEG($Image);
  Break;
  Case 3:
  $Img = @ImageCreateFromPNG($Image);
  Break;
  }
  //如果对象没有创建成功,则说明非图片文件
  IF(Empty($Img)){
  //如果是生成缩略图的时候出错,则需要删掉已经复制的文件
  IF($Type!=1){Unlink($Image);}
  Return False;
  }
  //如果是执行调整尺寸操作则
  IF($Type==1){
  $w=ImagesX($Img);
  $h=ImagesY($Img);
  $width = $w;
  $height = $h;
  IF($width>$Dw){
   $Par=$Dw/$width;
   $width=$Dw;
   $height=$height*$Par;
   IF($height>$Dh){
   $Par=$Dh/$height;
   $height=$Dh;
   $width=$width*$Par;
   }
  }ElseIF($height>$Dh){
   $Par=$Dh/$height;
   $height=$Dh;
   $width=$width*$Par;
   IF($width>$Dw){
   $Par=$Dw/$width;
   $width=$Dw;
   $height=$height*$Par;
   }
  }Else{
   $width=$width;
   $height=$height;
  }
  $nImg = ImageCreateTrueColor($width,$height);   //新建一个真彩色画布
  ImageCopyReSampled($nImg,$Img,0,0,0,0,$width,$height,$w,$h);//重采样拷贝部分图像并调整大小
  ImageJpeg ($nImg,$Image);     //以JPEG格式将图像输出到浏览器或文件
  Return True;
  //如果是执行生成缩略图操作则
  }Else{
  $w=ImagesX($Img);
  $h=ImagesY($Img);
  $width = $w;
  $height = $h;
  $nImg = ImageCreateTrueColor($Dw,$Dh);
  IF($h/$w>$Dh/$Dw){ //高比较大
   $width=$Dw;
   $height=$h*$Dw/$w;
   $IntNH=$height-$Dh;
   ImageCopyReSampled($nImg, $Img, 0, -$IntNH/1.8, 0, 0, $Dw, $height, $w, $h);
  }Else{   //宽比较大
   $height=$Dh;
   $width=$w*$Dh/$h;
   $IntNW=$width-$Dw;
   ImageCopyReSampled($nImg, $Img, -$IntNW/1.8, 0, 0, 0, $width, $Dh, $w, $h);
  }
  ImageJpeg ($nImg,$Image);
  Return True;
  }
}
&#63;>
<html><body>
<form method="post" enctype="multipart/form-data" name="form1">
 <table>
  <tr><td>上传图片</td></tr>
  <tr><td><input type="file" name="photo" size="20" /></td></tr>
 <tr><td><input type="submit" value="上传"/></td></tr>
 </table>
 允许上传的文件类型为:<&#63;=implode(', ',$phtypes)&#63;></form>
<&#63;php
 if($_SERVER['REQUEST_METHOD']=='POST'){
  if (!is_uploaded_file($_FILES["photo"][tmp_name])){
   echo "图片不存在";
   exit();
  }
  if(!is_dir('img')){//路径若不存在则创建
   mkdir('img');
  }
  $upfile=$_FILES["photo"]; 
  $pinfo=pathinfo($upfile["name"]);
  $name=$pinfo['basename'];//文件名
  $tmp_name=$upfile["tmp_name"];
  $file_type=$pinfo['extension'];//获得文件类型
  $showphpath=$path.$name;
  
  if(in_array($upfile["type"],$phtypes)){
   echo "文件类型不符！";
   exit();
   }
  if(move_uploaded_file($tmp_name,$path.$name)){
  echo "成功！";
 Img($showphpath,100,800,2);
  }
  echo "<img  src=\"".$showphpath."\" / alt="PHP实现图片压缩的两则实例_php技巧" >";
 }
&#63;>
</body>
</html>

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