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
   0 A0 k+ Z1 t3 R, x% e0 Z" D: W( H( ?
2. $FILENAME="image.thumb";
   
3. // 生成图片的宽度
   
4. $RESIZEWIDTH=400;
   
5. // 生成图片的高度
   
6. $RESIZEHEIGHT=400;
   7 W0 |1 _" c  z& Y7 E4 v. p
7. 
   
8. function ResizeImage($im,$maxwidth,$maxheight,$name){
   " w+ d3 E6 x: W" z* B2 V
9. $width = imagesx($im);
   , }; Q  @% }' T4 {! I
10. $height = imagesy($im);
    
11. if(($maxwidth && $width > $maxwidth) || ($maxheight && $height > $maxheight)){
    ! @9 h, s) E5 V" F; ~; F; M  @
12. if($maxwidth && $width > $maxwidth){
    . f- h' k. W3 G1 S: H
13. $widthratio = $maxwidth/$width;
    
14. $RESIZEWIDTH=true;
    
15. }
    
16. if($maxheight && $height > $maxheight){
    
17. $heightratio = $maxheight/$height;
    , \. l1 M& o! ~1 A! t
18. $RESIZEHEIGHT=true;
    
19. }
    9 ?' ~! E, b0 p4 n: [7 n# R1 D4 D
20. if($RESIZEWIDTH && $RESIZEHEIGHT){
    
21. if($widthratio < $heightratio){
    ' M7 D  e0 z# J5 v2 o& N) F  ?/ U
22. $ratio = $widthratio;
    
23. }else{
    
24. $ratio = $heightratio;
    
25. }
    
26. }elseif($RESIZEWIDTH){
    
27. $ratio = $widthratio;
    , _7 h0 U9 a4 K( h2 a! d3 K
28. }elseif($RESIZEHEIGHT){
    
29. $ratio = $heightratio;
    
30. }
    
31. $newwidth = $width * $ratio;
    
32. $newheight = $height * $ratio;
    
33. if(function_exists("imagecopyresampled")){
    
34. $newim = imagecreatetruecolor($newwidth, $newheight);
    3 ~: O1 T, B7 j$ ^- F2 E, D! {
35. imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
    
36. }else{
    ) @. }, I, c9 m. W  t1 U  [0 }" W
37. $newim = imagecreate($newwidth, $newheight);
    5 X* W0 k' ]9 Q9 }( R! N4 `
38. imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
    " T3 J: U" ]9 r" u0 s6 C& r
39. }
    
40. ImageJpeg ($newim,$name . ".jpg");
    ! Q6 C8 o* y) r
41. ImageDestroy ($newim);
    ) b$ N4 T" Y" a  i' V0 ~' y. r
42. }else{
    
43. ImageJpeg ($im,$name . ".jpg");
    6 N& D5 b) c8 Q+ ?
44. }
    & b' d2 [8 A. n/ H
45. }
    
46. 
    
47. if($_FILES['image']['size']){
    ; o% @$ q5 ^! d  b+ [
48. if($_FILES['image']['type'] == "image/pjpeg"){
    
49. $im = imagecreatefromjpeg($_FILES['image']['tmp_name']);
    
50. }elseif($_FILES['image']['type'] == "image/x-png"){
    
51. $im = imagecreatefrompng($_FILES['image']['tmp_name']);
    
52. }elseif($_FILES['image']['type'] == "image/gif"){
    
53. $im = imagecreatefromgif($_FILES['image']['tmp_name']);
    
54. } 2881064151
    " s4 N, K: U. k3 v! w
55. if($im){
    5 v2 [% |: ^% N& @7 h* V: t7 f6 y
56. if(file_exists("$FILENAME.jpg")){
    
57. unlink("$FILENAME.jpg");
    
58. }
    ! |+ G1 {8 l' Z0 G. A
59. ResizeImage($im,$RESIZEWIDTH,$RESIZEHEIGHT,$FILENAME);
    9 u8 H( I: C3 H2 c2 t/ v8 w0 U
60. ImageDestroy ($im);
    3 l: b! Q0 w% Q: A* x
61. }
    $ J" `' B8 ]6 p* p
62. }
    ( S! f. x2 [: A& r7 y# C* }  Z
63. ?>

复制代码

以下是测试代码(demo.php)

2 c! V1 m! w* T0 f代码如下:

1. <?php
   
2. include('ResizeImage.php');
   
3. if(!empty($_POST)){
   
4. echo($FILENAME.".jpg?cache=".rand(0,999999));
   2 G6 ]- g8 {  g0 z' o  f1 T+ G
5. }
   9 ]3 R- T6 H2 K* o1 h* G4 Z" s
6. ?>
   / X0 |% B2 i- ~
7. <form name="test" action="?submit=true" enctype="multipart/form-data" method="post" >
   
8. <input type="file" name="image" size="50" value="浏览"><p>
   
9. <input type="submit" value="上传图片">
   9 e, Q2 k$ l, I- {- w' v' \: f
10. </form>

复制代码