php调整图像尺寸的代码

3. /**********************

4. *@filename - path to the image
5. *@tmpname - temporary path to thumbnail
6. *@xmax - max width
7. *@ymax - max height
8. */
9. function resize_image($filename, $tmpname, $xmax, $ymax)
10. {
11. $ext = explode(".", $filename);
12. $ext = $ext[count($ext)-1];

13. if($ext == "jpg" || $ext == "jpeg")

14. $im = imagecreatefromjpeg($tmpname);
15. elseif($ext == "png")
16. $im = imagecreatefrompng($tmpname);
17. elseif($ext == "gif")
18. $im = imagecreatefromgif($tmpname);

19. $x = imagesx($im);

20. $y = imagesy($im);

21. if($x return $im;

22. if($x >= $y) {

23. $newx = $xmax;
24. $newy = $newx * $y / $x;
25. }
26. else {
27. $newy = $ymax;
28. $newx = $x / $y * $newy;
29. }

30. $im2 = imagecreatetruecolor($newx, $newy);

31. imagecopyresized($im2, $im, 0, 0, 0, 0, floor($newx), floor($newy), $x, $y);
32. return $im2;
33. }
34. ?>

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