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

2. function imageResizer($url, $width, $height) {
4. header('Content-type: image/jpeg');
6. list($width_orig, $height_orig) = getimagesize($url);
8. $ratio_orig = $width_orig/$height_orig;
10. if ($width/$height > $ratio_orig) {
11. $width = $height*$ratio_orig;
12. } else {
13. $height = $width/$ratio_orig;
14. }
16. // This resamples the image
17. $image_p = imagecreatetruecolor($width, $height);
18. $image = imagecreatefromjpeg($url);
19. imagecopyresampled($image_p, $image, 0, 0, 0, 0, $width, $height, $width_orig, $height_orig);
21. // Output the image
22. imagejpeg($image_p, null, 100);
24. }
26. //works with both POST and GET
27. $method = $_SERVER['REQUEST_METHOD'];
29. if ($method == 'GET') {
31. imageResize($_GET['url'], $_GET['w'], $_GET['h']);
33. } elseif ($method == 'POST') {
35. imageResize($_POST['url'], $_POST['w'], $_POST['h']);
36. }
38. // makes the process simpler
39. function loadImage($url, $width, $height){
40. echo 'image.php?url=', urlencode($url) ,
41. '&w=',$width,
42. '&h=',$height;
43. }
45. ?>

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1. //Above code would be in a file called image.php.
2. //Images would be displayed like this:
3. 

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