php生成图片与验证码图片生成原理

这款php生成图片与验证码图片生成原理代码,是由php gd库来支持,如果你的系统不能创建图片就把gd.dll前面的;去再,重起apache,如果是iis重起iis就OK了.创建图片后记得用ImageDestroy 清空内存.

php生成图片与验证码图片实例代码如下:

1. $w?$RESIZEWIDTH=$w:$RESIZEWIDTH=400;// 生成图片的宽度 
2. $h?$RESIZEHEIGHT=$h:$RESIZEHEIGHT=400;// 生成图片的高度 
3. function ResizeImage($im,$maxwidth,$maxheight,$name){ 
4.     $width = imagesx($im); 
5.     $height = imagesy($im); 
6.     if(($maxwidth && $width > $maxwidth) || ($maxheight && $height > $maxheight)){ 
7.         if($maxwidth && $width > $maxwidth){ 
8.             $widthratio = $maxwidth/$width; 
9.             $RESIZEWIDTH=true;//www.Vevb.com 
10.         } 
11.         if($maxheight && $height > $maxheight){ 
12.             $heightratio = $maxheight/$height; 
13.             $RESIZEHEIGHT=true; 
14.         } 
15.         if($RESIZEWIDTH && $RESIZEHEIGHT){ 
16.             if($widthratio < $heightratio){ 
17.                 $ratio = $widthratio; 
18.             }else{ 
19.                 $ratio = $heightratio; 
20.             } 
21.         }elseif($RESIZEWIDTH){ 
22.             $ratio = $widthratio; 
23.         }elseif($RESIZEHEIGHT){ 
24.             $ratio = $heightratio; 
25.         } 
26.         $newwidth = $width * $ratio; 
27.         $newheight = $height * $ratio; 
28.         if(function_exists("imagecopyresampled")){ 
29.               $newim = imagecreatetruecolor($newwidth, $newheight); 
30.               imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height); 
31.         }else{ 
32.             $newim = imagecreate($newwidth, $newheight); 
33.               imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height); 
34.         } 
35.         ImageJpeg ($newim,$name); 
36.         ImageDestroy ($newim); 
37.     }else{ 
38.         ImageJpeg ($im,$name); 
39.     } 
40. }  
41.  
42. if($_FILES['uploadfile']['size']){ 
43.     if($_FILES['uploadfile']['type'] == "image/pjpeg"){ 
44.         $im = imagecreatefromjpeg($_FILES['uploadfile']['tmp_name']); 
45.     }elseif($_FILES['uploadfile']['type'] == "image/x-png"){ 
46.         $im = imagecreatefrompng($_FILES['uploadfile']['tmp_name']); 
47.     }elseif($_FILES['uploadfile']['type'] == "image/gif"){ 
48.         $im = imagecreatefromgif($_FILES['uploadfile']['tmp_name']); 
49.     } 
50.     if($im){ 
51.         if(file_exists('bbs.jpg')){ 
52.             unlink('www.Vevb.com.jpg'); 
53.         } 
54.         ResizeImage($im,$RESIZEWIDTH,$RESIZEHEIGHT,'bbs.jpg'); 
55.         ImageDestroy ($im); 
56.    
57.     } 
58. } 
59. //$uploadfile="bbs.jpg"; 
60.