如何在服务器端调整图片大小

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：

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

   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;
        }

?>

//Above code would be in a file called image.php.
//Images would be displayed like this: