PHP一般情况下生成的缩略图都比较不理想

admin

PHP用GD库生成高质量的缩略图片,PHP一般情况下生成的缩略图都比较不理想。今天试用PHP，GD库来生成缩略图。虽然并不100%完美。可是也应该可以满足缩略图的要求了。

1. <?php
   $ u) O) p/ t% o" l7 D/ ^1 B/ G% X
2. $FILENAME="image.thumb";
   ) C# v9 d3 U$ e3 ?& j* Y. u7 D
3. // 生成图片的宽度
   
4. $RESIZEWIDTH=400;
   
5. // 生成图片的高度
   4 y; g7 X' V' S  A
6. $RESIZEHEIGHT=400;
   - `: e$ D6 l# H8 M# d
7. 
   7 d8 A$ g$ G9 r0 `$ _! b/ x5 z
8. function ResizeImage($im,$maxwidth,$maxheight,$name){
   
9. $width = imagesx($im);
   
10. $height = imagesy($im);
    ; C, E" U6 i6 K  g! h
11. if(($maxwidth && $width > $maxwidth) || ($maxheight && $height > $maxheight)){
    
12. if($maxwidth && $width > $maxwidth){
    
13. $widthratio = $maxwidth/$width;
    5 K, ]# W( Y' l1 e
14. $RESIZEWIDTH=true;
    
15. }
    
16. if($maxheight && $height > $maxheight){
    
17. $heightratio = $maxheight/$height;
    
18. $RESIZEHEIGHT=true;
    7 C, U" b$ ~# T( l
19. }
    
20. if($RESIZEWIDTH && $RESIZEHEIGHT){
    
21. if($widthratio < $heightratio){
    - }3 n  u3 h7 Q) e1 _+ P8 {
22. $ratio = $widthratio;
    * ?! c2 Q& H/ H3 ?2 y
23. }else{
    * c& y/ o* k9 H0 ?; r
24. $ratio = $heightratio;
    
25. }
    
26. }elseif($RESIZEWIDTH){
    " P% Y0 O8 |4 r( ~% M3 z
27. $ratio = $widthratio;
    
28. }elseif($RESIZEHEIGHT){
    
29. $ratio = $heightratio;
    
30. }
    
31. $newwidth = $width * $ratio;
    
32. $newheight = $height * $ratio;
    . f" V& y* b9 z5 M
33. if(function_exists("imagecopyresampled")){
    
34. $newim = imagecreatetruecolor($newwidth, $newheight);
    ; h, N# [; M; N4 y2 k
35. imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
    
36. }else{
    
37. $newim = imagecreate($newwidth, $newheight);
    " U, c9 q+ m! Q% O( J3 S
38. imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
    " K" _" a/ P0 S3 g) n2 e
39. }
    
40. ImageJpeg ($newim,$name . ".jpg");
    8 N" d# B+ p: Z& R2 w" x) {
41. ImageDestroy ($newim);
    0 }! d/ Q4 |% K; r, Y
42. }else{
    
43. ImageJpeg ($im,$name . ".jpg");
    
44. }
    * Z" q0 r# _0 z, |4 ?. G  w
45. }
    
46. 
    ; b* P- }- _" ^
47. if($_FILES['image']['size']){
    * \9 B6 Q* P8 ~- F
48. if($_FILES['image']['type'] == "image/pjpeg"){
    
49. $im = imagecreatefromjpeg($_FILES['image']['tmp_name']);
    , d, F9 K, Y- v4 B+ F7 M
50. }elseif($_FILES['image']['type'] == "image/x-png"){
    
51. $im = imagecreatefrompng($_FILES['image']['tmp_name']);
    9 F) `5 Q8 K7 _1 x2 Y6 V7 c; A  E
52. }elseif($_FILES['image']['type'] == "image/gif"){
    
53. $im = imagecreatefromgif($_FILES['image']['tmp_name']);
    . ^' `; k0 ?  W9 Z2 u: ^9 T
54. } 2881064151
    
55. if($im){
    
56. if(file_exists("$FILENAME.jpg")){
      k+ K5 W) `* Q* I6 I5 Y
57. unlink("$FILENAME.jpg");
    2 e. k/ t% W- f8 @- h) b# K5 d
58. }
    2 j, N. L  e% i( a$ ~
59. ResizeImage($im,$RESIZEWIDTH,$RESIZEHEIGHT,$FILENAME);
    ; f5 m* H& M$ ~6 T4 Q; b
60. ImageDestroy ($im);
    1 j. E' X& k$ S. o: s" b
61. }
    
62. }
    7 s3 ~5 [+ l: l# r& S0 X8 i
63. ?>

复制代码

以下是测试代码(demo.php)

代码如下:

8 g* e6 w4 W- C

1. <?php
   : g3 j5 i- K$ E# C: U3 {" E
2. include('ResizeImage.php');
   
3. if(!empty($_POST)){
   * b5 ~; X6 w% w
4. echo($FILENAME.".jpg?cache=".rand(0,999999));
   
5. }
   
6. ?>
   
7. <form name="test" action="?submit=true" enctype="multipart/form-data" method="post" >
   ' f" m+ l) k8 g  n, f
8. <input type="file" name="image" size="50" value="浏览"><p>
   ( b+ d1 p+ Y3 d7 V3 K! O' [
9. <input type="submit" value="上传图片">
   4 H( a& Z% ?% h8 ^1 H
10. </form>

复制代码

4 |- O4 J# H1 D! `