PHP implements image size adjustment on the server side

This article mainly introduces the PHP implementation of image size adjustment on the server side. Interested friends can refer to it. I hope it will be helpful to everyone.

The example in this article describes the method of adjusting the image size on the server side in PHP. 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="/static/imghwm/default1.png"  data-src="<?php loadImage(&#39;image.jpg&#39;, 50, 50) ? alt="PHP implements image size adjustment on the server side" >"  class="lazy"   alt="" />

Summary: The above is the entire content of this article, I hope it will be helpful to everyone's study.

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