本文主要向大家介绍了PHP语言图片压缩类,超低耗损,极大的保持清晰度，通过具体的内容向大家展示，希望对大家学习php语言有所帮助。

<?php

 /**

 * 分享请保持网址。尊重别人劳动成果。谢谢。

 * 图片压缩类：通过缩放来压缩。如果要保持源图比例，把参数$percent保持为1即可。

 * 即使原比例压缩，也可大幅度缩小。数码相机4M图片。也可以缩为700KB左右。如果缩小比例，则体积会更小。

 * 结果：可保存、可直接显示。

 */class imgcompress{

       private $src;

       private $image;

       private $imageinfo;

       private $percent = 0.5;

       /**

        * 图片压缩

        * @param $src 源图

        * @param float $percent  压缩比例

        */

       public function __construct($src, $percent=1)

       {

              $this->src = $src;

              $this->percent = $percent;

       }

       /** 高清压缩图片

        * @param string $saveName  提供图片名（可不带扩展名，用源图扩展名）用于保存。或不提供文件名直接显示

        */

       public function compressImg($saveName='')

       {

              $this->_openImage();

              if(!empty($saveName)) $this->_saveImage($saveName);  //保存

              else $this->_showImage();

       }

       /**

        * 内部：打开图片

        */

       private function _openImage()

       {

              list($width, $height, $type, $attr) = getimagesize($this->src);

              $this->imageinfo = array(

                     'width'=>$width,

                     'height'=>$height,

                     'type'=>image_type_to_extension($type,false),

                     'attr'=>$attr

              );

              $fun = "imagecreatefrom".$this->imageinfo['type'];

              $this->image = $fun($this->src);

              $this->_thumpImage();

       }

       /**

        * 内部：操作图片

        */

       private function _thumpImage()

       {

              $new_width = $this->imageinfo['width'] * $this->percent;

              $new_height = $this->imageinfo['height'] * $this->percent;

              $image_thump = imagecreatetruecolor($new_width,$new_height);

              //将原图复制带图片载体上面，并且按照一定比例压缩,极大的保持了清晰度

              imagecopyresampled($image_thump,$this->image,0,0,0,0,$new_width,$new_height,$this->imageinfo['width'],$this->imageinfo['height']);

              imagedestroy($this->image);

              $this->image = $image_thump;

       }

       /**

        * 输出图片:保存图片则用saveImage()

        */

       private function _showImage()

       {

              header('Content-Type: image/'.$this->imageinfo['type']);

              $funcs = "image".$this->imageinfo['type'];

              $funcs($this->image);

       }

       /**

        * 保存图片到硬盘：

        * @param  string $dstImgName  1、可指定字符串不带后缀的名称，使用源图扩展名 。2、直接指定目标图片名带扩展名。

        */

       private function _saveImage($dstImgName)

       {

              if(empty($dstImgName)) return false;

              $allowImgs = ['.jpg', '.jpeg', '.png', '.bmp', '.wbmp','.gif'];   //如果目标图片名有后缀就用目标图片扩展名 后缀，如果没有，则用源图的扩展名

              $dstExt =  strrchr($dstImgName ,".");

              $sourseExt = strrchr($this->src ,".");

              if(!empty($dstExt)) $dstExt =strtolower($dstExt);

              if(!empty($sourseExt)) $sourseExt =strtolower($sourseExt);

              //有指定目标名扩展名

              if(!empty($dstExt) && in_array($dstExt,$allowImgs)){

                     $dstName = $dstImgName;

              }elseif(!empty($sourseExt) && in_array($sourseExt,$allowImgs)){

                     $dstName = $dstImgName.$sourseExt;

              }else{

                     $dstName = $dstImgName.$this->imageinfo['type'];

              }

              $funcs = "image".$this->imageinfo['type'];

              $funcs($this->image,$dstName);

       }

       /**

        * 销毁图片

        */

       public function __destruct(){

              imagedestroy($this->image);

       }

}

$source = '1.png';

$dst_img = '../copy1.png'; //可加存放路径

$percent = 1;  #原图压缩，不缩放

$image = (new imgcompress($source,$percent))->compressImg($dst_img);

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