<?php 

class image_blur{

/**
     * 圖片高斯模糊（適用於png/jpg/gif格式）
     * @param $srcImg 原圖片
     * @param $savepath 儲存路徑
     * @param $savename 儲存名字
     * @param $positon 模糊程度 
     *
     *基於Martijn Frazer程式碼的擴充， 感謝 Martijn Frazer
     */
    public function gaussian_blur($srcImg,$savepath=null,$savename=null,$blurFactor=3){
        $gdImageResource=$this->image_create_from_ext($srcImg);
        $srcImgObj=$this->blur($gdImageResource,$blurFactor);
        $temp = pathinfo($srcImg);
        $name = $temp['basename'];
        $path = $temp['dirname'];
        $exte = $temp['extension'];
        $savename = $savename ? $savename : $name;
        $savepath = $savepath ? $savepath : $path;
        $savefile = $savepath .'/'. $savename;
        $srcinfo = @getimagesize($srcImg);
        
        switch ($srcinfo[2]) {
            case 1: imagegif($srcImgObj, $savefile); break;
            case 2: imagejpeg($srcImgObj, $savefile); break;
            case 3: imagepng($srcImgObj, $savefile); break;
            default: return '儲存失敗'; //儲存失敗
        }

        return $savefile;
        imagedestroy($srcImgObj);
    }

    /**
    * Strong Blur
    *
    * @param  $gdImageResource  圖片資源
    * @param  $blurFactor          可選擇的模糊程度 
    *  可選擇的模糊程度  0使用   3預設   超過5時 極其模糊
    * @return GD image 圖片資源型別
    * @author Martijn Frazer, idea based on http://stackoverflow.com/a/20264482
    */
    private function blur($gdImageResource, $blurFactor = 3)
    {
        // blurFactor has to be an integer
        $blurFactor = round($blurFactor);

        $originalWidth = imagesx($gdImageResource);
        $originalHeight = imagesy($gdImageResource);

        $smallestWidth = ceil($originalWidth * pow(0.5, $blurFactor));
        $smallestHeight = ceil($originalHeight * pow(0.5, $blurFactor));

        // for the first run, the previous image is the original input
        $prevImage = $gdImageResource;
        $prevWidth = $originalWidth;
        $prevHeight = $originalHeight;

        // scale way down and gradually scale back up, blurring all the way
        for($i = 0; $i < $blurFactor; $i += 1)
        {    
            // determine dimensions of next image
            $nextWidth = $smallestWidth * pow(2, $i);
            $nextHeight = $smallestHeight * pow(2, $i);

            // resize previous image to next size
            $nextImage = imagecreatetruecolor($nextWidth, $nextHeight);
            imagecopyresized($nextImage, $prevImage, 0, 0, 0, 0, 
              $nextWidth, $nextHeight, $prevWidth, $prevHeight);

            // apply blur filter
            imagefilter($nextImage, IMG_FILTER_GAUSSIAN_BLUR);

            // now the new image becomes the previous image for the next step
            $prevImage = $nextImage;
            $prevWidth = $nextWidth;
            $prevHeight = $nextHeight;
        }

        // scale back to original size and blur one more time
        imagecopyresized($gdImageResource, $nextImage, 
        0, 0, 0, 0, $originalWidth, $originalHeight, $nextWidth, $nextHeight);
        imagefilter($gdImageResource, IMG_FILTER_GAUSSIAN_BLUR);

        // clean up
        imagedestroy($prevImage);

        // return result
        return $gdImageResource;
    }

    private function image_create_from_ext($imgfile)
    {
        $info = getimagesize($imgfile);
        $im = null;
        switch ($info[2]) {
        case 1: $im=imagecreatefromgif($imgfile); break;
        case 2: $im=imagecreatefromjpeg($imgfile); break;
        case 3: $im=imagecreatefrompng($imgfile); break;
        }
        return $im;
    }

}
$image_blur = new image_blur();

$image_blur->gaussian_blur("./2.jpg",null,null,5);