Sample reference for scaling images in PHP

This article introduces a PHP code that implements a blooming image in equal proportions when making an avatar function. Friends in need can refer to it.

The following is a piece of code I wrote when I was doing an avatar processing program.

Achievement: Upload an image, save it as a large avatar, and then shrink it and save it as a small avatar.

The specific code is as follows:

<?php
/**
* 等比例绽放图片大小
* edit by bbs.it-home.org
*/
public function drawImg($from,$w=100,$h=100,$newfile){
  $info = getimagesize($from);
  switch ($info[2]){
  case 1:
  $im = imagecreatefromgif($from);
     break;
     case 2:
  $im = imagecreatefromjpeg($from);
  break;
     case 3:
  $im = imagecreatefrompng($from);
  break;
     default:
  exit('不支持的图像格式');
     break;
 }
 $temp = pathinfo($from);
 $name = $temp["basename"];//文件名
 $dir = $temp["dirname"];//文件所在的文件夹
 $extension = $temp["extension"];//文件扩展名
 $width = $info[0];//获取图片宽度
 $height = $info[1];//获取图片高度
 $per1 = round($width/$height,2);//计算原图长宽比
 $per2 = round($w/$h,2);//计算缩略图长宽比
 //计算缩放比例
 if($per1>$per2||$per1==$per2)
 {
     //原图长宽比大于或者等于缩略图长宽比，则按照宽度优先
     $per=$w/$width;
 }
 if($per1<$per2)
 {
     //原图长宽比小于缩略图长宽比，则按照高度优先
     $per=$h/$height;
 }
 $temp_w = intval($width*$per);//计算原图缩放后的宽度
 $temp_h = intval($height*$per);//计算原图缩放后的高度
 $dst_im = imagecreatetruecolor($temp_w, $temp_h);
 //调整大小
 imagecopyresized($dst_im, $im, 0, 0, 0, 0, $temp_w, $temp_h, $width, $height);
 //输出缩小后的图像
 //exit($newfile);
 imagejpeg($dst_im,$dir.'/'.$newfile);
 imagedestroy($dst_im);
 imagedestroy($im);
}
?>

Note: The imagejpeg() function, without adding the save path at the front, has been unsuccessful! After testing, I realized that I need to add a save path!