Introduction to how to resize images on the server side in PHP

This article mainly introduces the method of PHP to adjust the image size on the server side. The example analyzes the related skills of imageResizer and loadimage to operate the image. Friends in need can refer to it.

The example of this article describes the PHP implementation. How to resize images on the server side. Share it with everyone for your reference. The specific analysis is as follows:

Completing image size adjustment on the server side will have many advantages over processing in the browser.
This article introduces how PHP resizes images on the server side.

The code includes two parts:

① imageResizer() is used to process the image
② loadimage() inserts the image url in a simpler format

<?php
 function imageResizer($url, $width, $height) {
  header(&#39;Content-type: image/jpeg&#39;);
  list($width_orig, $height_orig) = getimagesize($url);
  $ratio_orig = $width_orig/$height_orig;
  if ($width/$height > $ratio_orig) {
   $width = $height*$ratio_orig;
  } else {
   $height = $width/$ratio_orig;
  }
  // This resamples the image
  $image_p = imagecreatetruecolor($width, $height);
  $image = imagecreatefromjpeg($url);
  imagecopyresampled($image_p, $image, 0, 0, 0, 0, $width, $height, $width_orig, $height_orig);
  // Output the image
  imagejpeg($image_p, null, 100);
 }
 //works with both POST and GET
 $method = $_SERVER[&#39;REQUEST_METHOD&#39;];
 if ($method == &#39;GET&#39;) {
  imageResize($_GET[&#39;url&#39;], $_GET[&#39;w&#39;], $_GET[&#39;h&#39;]);
  } elseif ($method == &#39;POST&#39;) {
  imageResize($_POST[&#39;url&#39;], $_POST[&#39;w&#39;], $_POST[&#39;h&#39;]);
  }
 // makes the process simpler
 function loadImage($url, $width, $height){
  echo &#39;image.php?url=&#39;, urlencode($url) ,
  &#39;&w=&#39;,$width,
  &#39;&h=&#39;,$height;
 }
?>

Usage:

//Above code would be in a file called image.php.
//Images would be displayed like this:
<img src="<?php loadImage(&#39;image.jpg&#39;, 50, 50) ?>" alt="" />

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