这篇文章主要介绍了PHP生成等比缩略图类和自定义函数分享,分别封装成了一个类和自定义函数,需要的朋友可以参考下。

共有两种等比例缩略图方法可以借鉴

一、为类文件，实例化之后即可使用

二、为自定义方法，比较轻巧

类文件代码如下:

1. $resizeimage = new resizeimage("./shawn.jpg", "200", "100", "0","../pic/shawnsun.jpg");
2. //实例化下面的类,就能生成缩略图
3. //其中,源文件和缩略图地址可以相同,200,100分别代表宽和高，第四个参数为可选 0不截图，1为截图
4. <?php
5. class resizeimage{
6. //图片类型
7. public $type;
8. //实际宽度
9. public $width;
10. //实际高度
11. public $height;
12. //改变后的宽度
13. public $resize_width;
14. //改变后的高度
15. public $resize_height;
16. //是否裁图
17. public $cut;
18. //源图象
19. public $srcimg;
20. //目标图象地址
21. public $dstimg;
22. //临时创建的图象
23. public $im;
24. function resizeimage($img, $wid, $hei,$c,$dstpath){
25. $this--->srcimg = $img;
26. $this->resize_width = $wid;
27. $this->resize_height = $hei;
28. $this->cut = $c;
29. //图片的类型
30. $this->type = strtolower(substr(strrchr($this->srcimg,"."),1));
31. //初始化图象
32. $this->initi_img();
33. //目标图象地址
34. $this->dst_img($dstpath);
35. //W & H
36. $this->width = imagesx($this->im);
37. $this->height = imagesy($this->im);
38. //生成图象
39. $this->newimg();
40. ImageDestroy ($this->im);
41. }
42. function newimg(){
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,
55. $this->resize_height, (($this->height)*$resize_ratio),
56. $this->height
57. );
58. ImageJpeg ($newimg,$this->dstimg);
59. }
60. if($ratio<$resize_ratio)
61. //宽度优先
62. {
63. $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);
64. imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,
65. $this->resize_height, $this->width,
66. (($this->width)/$resize_ratio)
67. );
68. ImageJpeg ($newimg,$this->dstimg);
69. }
70. }
71. else
72. //不裁图
73. {
74. if($ratio>=$resize_ratio)
75. {
76. $newimg = imagecreatetruecolor($this->resize_width,
77. ($this->resize_width)/$ratio
78. );
79. imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,
80. ($this->resize_width)/$ratio, $this->width,
81. $this->height
82. );
83. ImageJpeg ($newimg,$this->dstimg);
84. }
85. if($ratio<$resize_ratio)
86. {
87. $newimg = imagecreatetruecolor(($this->resize_height)*$ratio,
88. $this->resize_height
89. );
90. imagecopyresampled($newimg, $this->im, 0, 0, 0, 0,
91. ($this->resize_height)*$ratio,
92. $this->resize_height, $this->width,
93. $this->height
94. );
95. ImageJpeg ($newimg,$this->dstimg);
96. }
97. }
98. }
99. //初始化图象
100. function initi_img(){
101. if($this->type=="jpg")
102. {
103. $this->im = imagecreatefromjpeg($this->srcimg);
104. }
105. if($this->type=="gif")
106. {
107. $this->im = imagecreatefromgif($this->srcimg);
108. }
109. if($this->type=="png")
110. {
111. $this->im = imagecreatefrompng($this->srcimg);
112. }
113. }
114. //图象目标地址
115. function dst_img($dstpath){
116. $full_length = strlen($this->srcimg);
117. $type_length = strlen($this->type);
118. $name_length = $full_length-$type_length;
119. $name = substr($this->srcimg,0,$name_length-1);
120. $this->dstimg = $dstpath;
121. //echo $this->dstimg;
122. }
123. }
124. ?>

自定义方法，代码如下:

1. thumbs('shawn.jpg','shawnsun.jpg',100,100);
2. <?php
3. function thumbs($FileName,$SaveTo,$SetW,$SetH){
4. $IMGInfo= getimagesize($FileName);
5. if(!$IMGInfo) return false;
6. if($IMGInfo['mime']== "image/pjpeg" || $IMGInfo['mime']=="image/jpeg"){
7. $ThisPhoto= imagecreatefromjpeg($FileName);
8. }elseif($IMGInfo['mime']== "image/x-png" || $IMGInfo['mime']== "image/png"){
9. $ThisPhoto= imagecreatefrompng($FileName);
10. }elseif($IMGInfo['mime']== "image/gif"){
11. $ThisPhoto=imagecreatefromgif($FileName);
12. }
13. $width=$IMGInfo[0];
14. $height=$IMGInfo[1];
15. $scalc = max($width/$SetW,$height/$SetH);
16. $nw = intval($width/$scalc);
17. $nh = intval($height/$scalc);
18. echo "缩略大小：w$nw,h$nh <br /-->";
19. if($SetW-$nw == 1){$nw = $SetW;}
20. if($SetH-$nh == 1){$nh = $SetH;}
21. echo "+修正1像素： w$nw,h$nh<br>";
22. //补宽
23. if($SetW-$nw > 0){
24. $nh = $nh +(($nh/$nw) * ($SetW-$nw));
25. echo "*需补宽".($SetW-$nw).",陪补高".(($nh/$nw) * ($SetW-$nw))." <br>";
26. $nw = $SetW;
27. }
28. //补高
29. if($SetH-$nh > 0){
30. $nw = $nw + (($nw/$nh) * ($SetH-$nh));
31. echo "*需补高".($SetH-$nh).",陪补宽". (($nw/$nh) * ($SetH-$nh)) ."<br>";
32. $nh = $SetH;
33. }
34. $nw = intval($nw);
35. $nh = intval($nh);
36. echo "+修正大小：w$nw,h$nh<br>";
37. $px = ($SetW - $nw)/2;
38. $py = ($SetH - $nh)/2;
39. echo "窗口大小：w$SetW,h$SetH <br>";
40. echo "+偏移修正：x$px,y$py <br>";
41. $NewPhoto=imagecreatetruecolor($SetW,$SetH);
42. imagecopyresized($NewPhoto,$ThisPhoto,$px,$py,0,0,$nw,$nh,$width,$height);
43. ImageJpeg ($NewPhoto,$SaveTo);
44. return true;
45. }
46. ?>