php实现在服务器端调整图片大小的方法

本文实例讲述了php实现在服务器端调整图片大小的方法。分享给大家供大家参考。具体分析如下：

在服务器端完成图片大小的调整，会比在浏览器的处理有很多的好处。
本文介绍了PHP如何在服务器端调整图片大小。

代码包括两部分：

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

    <?php
     function imageResizer($url, $width, $height) {
      header('Content-type: image/jpeg');
      list($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 = $_SERVER['REQUEST_METHOD'];
     if ($method == 'GET') {
      imageResize($_GET['url'], $_GET['w'], $_GET['h']);
      } elseif ($method == 'POST') {
      imageResize($_POST['url'], $_POST['w'], $_POST['h']);
      }
     // makes the process simpler
     function loadImage($url, $width, $height){
      echo 'image.php?url=', urlencode($url) ,
      '&w;=',$width,
      '&h;=',$height;
     }
    ?>

用法：

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

希望本文所述对大家的php程序设计有所帮助。