PHP图片压缩

//直接调用就可以了

<?php
namespace think\admin\storage;
/**
 * 图片压缩
 * Class Compress
 * @package EasyAdmin\upload\driver
 */
class Compress {
    private $src;
    private $image;
    private $imageinfo;
    private $percent = 0.5;
    /**
     * 图片压缩
     * @param string $src 源图
     * @param float $percent 压缩比例
     */
    public function __construct($src, $percent=1.0) {
        $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
     * @param integer $new_width
     * @param integer $new_height
     */
    public function compressImg($saveName='',$new_width = 0,$new_height = 0) {
        $this->_openImage();
        $this->_thumpImage($new_width,$new_height);
        if(!empty($saveName)) $this->_saveImage($saveName);  //保存
        else $this->_showImage();
    }

    /** 裁剪图片
     * @param array $rect x,y,w,h,   width,height 裁剪位置 屏幕宽高(坐标相对,原图)
     * @param string $saveName  提供图片名（可不带扩展名，用源图扩展名）用于保存。或不提供文件名直接显示
     */
    public function tailoring($rect=[],$saveName='') {
        if( !isset($rect['width'],$rect['height']) ) return $saveName;
        if( 0 >= $rect['width'] || 0 >= $rect['height'] ) return $saveName;
        $this->_openImage();
        !isset($rect['x']) && $rect['x'] = 0;
        !isset($rect['y']) && $rect['y'] = 0;
        !isset($rect['w']) && $rect['w'] = $this->imageinfo['width'];
        !isset($rect['h']) && $rect['h'] = $this->imageinfo['height'];
        $rate = $this->imageinfo['width']/$rect['width'];
        $rect['x'] = $rate*$rect['x'];
        $rect['w'] = $rate*$rect['w'];
        $rate = $this->imageinfo['height']/$rect['height'];
        $rect['y'] = $rate*$rect['y'];
        $rect['h'] = $rate*$rect['h'];
        $this->_tailoring($rect);
        if(!empty($saveName)) $this->_saveImage($saveName);  //保存
        else $this->_showImage();
    }
    /** 裁剪
     * @param array $rect x,y,w,h 裁剪位置
     */
    public function _tailoring($rect){
        $image_thump = imagecreatetruecolor($rect['w'],$rect['h']);
        imagecopy($image_thump,$this->image,0,0,$rect['x'],$rect['y'],$rect['w'],$rect['h']);
        imagedestroy($this->image);
        $this->image = $image_thump;
    }
    /**
     * 内部：打开图片
     */
    private function _openImage(){
        list($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);

    }
    /**
     * 内部：操作图片
     * @param integer $new_width
     * @param integer $new_height
     */
    private function _thumpImage($new_width = 0,$new_height=0){
        0 === $new_width && $new_width = $this->imageinfo['width'] * $this->percent;
        0 === $new_height && $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(){
        $this->image && imagedestroy($this->image);
    }
}