php生成缩略图类,支持自定义高和宽,还支持按高和宽截图,实例代码如下:

1. <?php
2. class resizeimage
3. {
4. //图片类型
5. var $type;
6. //实际宽度
7. var $width;
8. //实际高度
9. var $height;
10. //改变后的宽度
11. var $resize_width;
12. //改变后的高度
13. var $resize_height;
14. //是否裁图
15. var $cut;
16. //源图象
17. var $srcimg;
18. //目标图象地址
19. var $dstimg;
20. //临时创建的图象
21. var $im;
22. function resizeimage($img, $wid, $hei,$c,$dstpath)
23. { //开源代码phpfensi.com
24. $this->srcimg = $img;
25. $this->resize_width = $wid;
26. $this->resize_height = $hei;
27. $this->cut = $c;
28. //图片的类型
29. $this->type = strtolower(substr(strrchr($this->srcimg,"."),1));
30. //初始化图象
31. $this->initi_img();
32. //目标图象地址
33. $this -> dst_img($dstpath);
34. //--
35. $this->width = imagesx($this->im);
36. $this->height = imagesy($this->im);
37. //生成图象
38. $this->newimg();
39. ImageDestroy ($this->im);
40. }
41. function newimg()
42. {
43. //改变后的图象的比例
44. $resize_ratio = ($this->resize_width)/($this->resize_height);
45. //实际图象的比例
46. $ratio = ($this->width)/($this->height);
47. if(($this->cut)=="1")
48. //裁图
49. {
50. if($ratio>=$resize_ratio)
51. //高度优先
52. {
53. $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);
54. imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,$this->resize_height, (($this->height)*$resize_ratio), $this->height);
55. ImageJpeg ($newimg,$this->dstimg);
56. }
57. if($ratio<$resize_ratio)
58. //宽度优先
59. {
60. $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);
61. imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, $this->resize_height, $this->width, (($this->width)/$resize_ratio));
62. ImageJpeg ($newimg,$this->dstimg);
63. }
64. }
65. else
66. //不裁图
67. {
68. if($ratio>=$resize_ratio)
69. {
70. $newimg = imagecreatetruecolor($this->resize_width,($this->resize_width)/$ratio);
71. imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, ($this->resize_width)/$ratio, $this->width, $this->height);
72. ImageJpeg ($newimg,$this->dstimg);
73. }
74. if($ratio<$resize_ratio)
75. {
76. $newimg = imagecreatetruecolor(($this->resize_height)*$ratio,$this->resize_height);
77. imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, ($this->resize_height)*$ratio, $this->resize_height, $this->width, $this->height);
78. ImageJpeg ($newimg,$this->dstimg);
79. }
80. }
81. }
82. //初始化图象
83. function initi_img()
84. {
85. if($this->type=="jpg")
86. {
87. $this->im = imagecreatefromjpeg($this->srcimg);
88. }
89. if($this->type=="gif")
90. {
91. $this->im = imagecreatefromgif($this->srcimg);
92. }
93. if($this->type=="png")
94. {
95. $this->im = imagecreatefrompng($this->srcimg);
96. }
97. }
98. //图象目标地址
99. function dst_img($dstpath)
100. {
101. $full_length = strlen($this->srcimg);
102. $type_length = strlen($this->type);
103. $name_length = $full_length-$type_length;
104. $name = substr($this->srcimg,0,$name_length-1);
105. $this->dstimg = $dstpath;
106. //echo $this->dstimg;
107. }
108. }
109. $resizeimage = new resizeimage("11.jpg", "200", "150", "1","17.jpg");