本文实例讲述了php生成图片缩略图功能。分享给大家供大家参考，具体如下：

完整代码如下：

1. <?php
2. /*
3. * Created on 2011-3-18
4. *
5. * To change the template for this generated file go to
6. * Window - Preferences - PHPeclipse - PHP - Code Templates
7. */
8. /*构造函数-生成缩略图+水印,参数说明:
9. $srcFile-图片文件名,
10. $dstFile-另存文件名,
11. $markwords-水印文字,
12. $markimage-水印图片,
13. $dstW-图片保存宽度,
14. $dstH-图片保存高度,
15. $rate-图片保存品质*/
16. makethumb("1.jpg","aa/b.jpg","50","50");
17. functionmakethumb($srcFile,$dstFile,$dstW,$dstH,$rate= 100,$markwords= null,$markimage= null) {
18. $data=GetImageSize($srcFile);
19. switch($data[2]) {
20. case1:
21. $im= @ImageCreateFromGIF($srcFile);
22. break;
23. case2:
24. $im= @ImageCreateFromJPEG($srcFile);
25. break;
26. case3:
27. $im= @ImageCreateFromPNG($srcFile);
28. break;
29. }
30. if(!$im)returnFalse;
31. $srcW= ImageSX($im);
32. $srcH= ImageSY($im);
33. $dstX= 0;
34. $dstY= 0;
35. if($srcW*$dstH>$srcH*$dstW) {
36. $fdstH=round($srcH*$dstW/$srcW);
37. $dstY=floor(($dstH-$fdstH) / 2);
38. $fdstW=$dstW;
39. }else{
40. $fdstW=round($srcW*$dstH/$srcH);
41. $dstX=floor(($dstW-$fdstW) / 2);
42. $fdstH=$dstH;
43. }
44. $ni= ImageCreateTrueColor($dstW,$dstH);
45. $dstX= ($dstX< 0) ? 0 :$dstX;
46. $dstY= ($dstX< 0) ? 0 :$dstY;
47. $dstX= ($dstX> ($dstW/ 2)) ?floor($dstW/ 2) :$dstX;
48. $dstY= ($dstY> ($dstH/ 2)) ?floor($dstH/ s) :$dstY;
49. $white= ImageColorAllocate($ni, 255, 255, 255);
50. $black= ImageColorAllocate($ni, 0, 0, 0);
51. imagefilledrectangle($ni, 0, 0,$dstW,$dstH,$white);// 填充背景色
52. ImageCopyResized($ni,$im,$dstX,$dstY, 0, 0,$fdstW,$fdstH,$srcW,$srcH);
53. if($markwords!= null) {
54. $markwords= iconv("gb2312","UTF-8",$markwords);
55. //转换文字编码
56. ImageTTFText($ni, 20, 30, 450, 560,$black,"simhei.ttf",$markwords);//写入文字水印
57. //参数依次为，文字大小|偏转度|横坐标|纵坐标|文字颜色|文字类型|文字内容
58. }elseif($markimage!= null) {
59. $wimage_data=GetImageSize($markimage);
60. switch($wimage_data[2]) {
61. case1:
62. $wimage= @ImageCreateFromGIF($markimage);
63. break;
64. case2:
65. $wimage= @ImageCreateFromJPEG($markimage);
66. break;
67. case3:
68. $wimage= @ImageCreateFromPNG($markimage);
69. break;
70. }
71. imagecopy($ni,$wimage, 500, 560, 0, 0, 88, 31);//写入图片水印,水印图片大小默认为88*31
72. imagedestroy($wimage);
73. } //phpfensi.com
74. ImageJpeg($ni,$dstFile,$rate);
75. ImageJpeg($ni,$srcFile,$rate);
76. imagedestroy($im);
77. imagedestroy($ni);
78. }
79. ?>