How to generate blurry images in PHP

This article mainly introduces the method of generating blurred pictures in PHP, and involves the implementation techniques of PHP Gaussian algorithm to realize the picture blur function. Friends who need it can refer to it. I hope it can help everyone.

<?php
class image_blur{
/**
  * 图片高斯模糊（适用于png/jpg/gif格式）
  * @param $srcImg 原图片
  * @param $savepath 保存路径
  * @param $savename 保存名字
  * @param $positon 模糊程度
  *
  *基于Martijn Frazer代码的扩充， 感谢 Martijn Frazer
  */
 public function gaussian_blur($srcImg,$savepath=null,$savename=null,$blurFactor=3){
  $gdImageResource=$this->image_create_from_ext($srcImg);
  $srcImgObj=$this->blur($gdImageResource,$blurFactor);
  $temp = pathinfo($srcImg);
  $name = $temp[&#39;basename&#39;];
  $path = $temp[&#39;dirname&#39;];
  $exte = $temp[&#39;extension&#39;];
  $savename = $savename ? $savename : $name;
  $savepath = $savepath ? $savepath : $path;
  $savefile = $savepath .&#39;/&#39;. $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 &#39;保存失败&#39;; //保存失败
  }
  return $savefile;
  imagedestroy($srcImgObj);
 }
 /**
 * Strong Blur
 *
 * @param $gdImageResource 图片资源
 * @param $blurFactor   可选择的模糊程度
 * 可选择的模糊程度 0使用 3默认 超过5时 极其模糊
 * @return GD image 图片资源类型
 * @author Martijn Frazer, idea based on http://stackoverflow.com/a/20264482
 */
 private function blur($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("./1.jpg",null,null,3);
?>

The original image effect:

##The effect after generating the blurred image:

Have you learned it? Hurry up and give it a try.

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