How to blur pictures in PHP

This article mainly introduces how to generate blurry images in PHP. Interested friends can refer to it. I hope it will be helpful to everyone.

The code is as follows:

<?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);
?>

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