没有GD库也可以用图形验证码（限数字加字母）

最新推荐文章于 2022-10-17 10:26:11 发布

flashlm

最新推荐文章于 2022-10-17 10:26:11 发布

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分类专栏： 12-PHP编程文章标签：图形 function header im session 服务器

本文链接：https://blog.youkuaiyun.com/flashlm/article/details/1656749

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本文介绍了一种在服务器未安装GD2库的情况下生成图形验证码的方法。通过判断GD库的存在与否来选择不同的生成方式，当GD2存在时使用PNG格式输出，不存在时则采用位图格式，并详细展示了相应的PHP代码。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

服务器由于重新编辑了PHP，漏掉了GD2的安装，图形验证码全部失效，只好搞过另一个图形验证码程序。
下面只提供生成图片的代码：

<? php

* Filename: ck.php

* Author: flashlm

* Update: 07-06-18

session_start ();

$auth_num = "" ;

srand (( double ) microtime () * 1000000 );

$auth_num_k = md5 ( rand ( 0 , 9999 ));

$auth_num = substr ( $auth_num_k , 10 , 4 );

session_register ( ' auth_num ' );

// 判断是否安装了GD2，如果装了

if ( function_exists ( ' imagecreate ' ) && function_exists ( ' imagecolorallocate ' ) && function_exists ( ' imagepng ' ) &&

function_exists ( ' imagesetpixel ' ) && function_exists ( ' imageString ' ) && function_exists ( ' imagedestroy ' ) && function_exists ( ' imagefilledrectangle ' ) && function_exists ( ' imagerectangle ' )){

Header ( " Content-type:image/PNG " );

$im = imagecreate( 63 , 20 );

$black = ImageColorAllocate( $im , 255 , 255 , 255 );

$white = ImageColorAllocate( $im , 255 , 255 , 255 );

$gray = ImageColorAllocate( $im , 20 , 20 , 20 );

// ImageFill($im,63,20,$black);//这行不知道为什么在我公司的服务器上出错误，换个空间ok

imagestring( $im , 5 , 10 , 3 , $auth_num , $gray );

for ( $i = 0 ; $i < 200 ; $i ++ )

{

$randcolor = ImageColorallocate( $im , rand ( 0 , 255 ) , rand ( 0 , 255 ) , rand ( 0 , 255 ));

imagesetpixel( $im , rand () % 70 , rand () % 30 , $randcolor );

}

ImagePNG( $im );

ImageDestroy( $im );

} else { // 如果没有安装GD2

//禁止缓存

header ( " Pragma:no-cache " );

header ( " Cache-control:no-cache " );

header ( " ContentType: Image/BMP " );

$Color [ 0 ] = chr ( 0 ) . chr ( 0 ) . chr ( 0 );

$Color [ 1 ] = chr ( 255 ) . chr ( 255 ) . chr ( 255 );

// 0-9,a-z字符的数据

$_Num [ 0 ] = " 1110000111110111101111011110111101001011110100101111010010111101001011110111101111011110111110000111 " ;

$_Num [ 1 ] = " 1111011111110001111111110111111111011111111101111111110111111111011111111101111111110111111100000111 " ;

$_Num [ 2 ] = " 1110000111110111101111011110111111111011111111011111111011111111011111111011111111011110111100000011 " ;

$_Num [ 3 ] = " 1110000111110111101111011110111111110111111100111111111101111111111011110111101111011110111110000111 " ;

$_Num [ 4 ] = " 1111101111111110111111110011111110101111110110111111011011111100000011111110111111111011111111000011 " ;

$_Num [ 5 ] = " 1100000011110111111111011111111101000111110011101111111110111111111011110111101111011110111110000111 " ;

$_Num [ 6 ] = " 1111000111111011101111011111111101111111110100011111001110111101111011110111101111011110111110000111 " ;

$_Num [ 7 ] = " 1100000011110111011111011101111111101111111110111111110111111111011111111101111111110111111111011111 " ;

$_Num [ 8 ] = " 1110000111110111101111011110111101111011111000011111101101111101111011110111101111011110111110000111 " ;

$_Num [ 9 ] = " 1110001111110111011111011110111101111011110111001111100010111111111011111111101111011101111110001111 " ;

$_Num [ 10 ] = " 1111011111111101111111101011111110101111111010111111101011111100000111110111011111011101111000100011 " ;

$_Num [ 11 ] = " 1000000111110111101111011110111101110111110000111111011101111101111011110111101111011110111000000111 " ;

$_Num [ 12 ] = " 1110000011110111101110111110111011111111101111111110111111111011111111101111101111011101111110001111 " ;

$_Num [ 13 ] = " 1000001111110111011111011110111101111011110111101111011110111101111011110111101111011101111000001111 " ;

$_Num [ 14 ] = " 1000000111110111101111011011111101101111110000111111011011111101101111110111111111011110111000000111 " ;

$_Num [ 15 ] = " 1000000111110111101111011011111101101111110000111111011011111101101111110111111111011111111000111111 " ;

$_Num [ 16 ] = " 1110000111110111011110111101111011111111101111111110111111111011100011101111011111011101111110001111 " ;

$_Num [ 17 ] = " 1000100011110111011111011101111101110111110000011111011101111101110111110111011111011101111000100011 " ;

$_Num [ 18 ] = " 1100000111111101111111110111111111011111111101111111110111111111011111111101111111110111111100000111 " ;

$_Num [ 19 ] = " 1110000011111110111111111011111111101111111110111111111011111111101111111110111110111011111000011111 " ;

$_Num [ 20 ] = " 1000100011110111011111011011111101011111110001111111010111111101101111110110111111011101111000100011 " ;

$_Num [ 21 ] = " 1000111111110111111111011111111101111111110111111111011111111101111111110111111111011110111000000011 " ;

$_Num [ 22 ] = " 1000100011110010011111001001111100100111110101011111010101111101010111110101011111010101111001010011 " ;

$_Num [ 23 ] = " 1000100011110011011111001101111101010111110101011111010101111101100111110110011111011001111000110111 " ;

$_Num [ 24 ] = " 1110001111110111011110111110111011111011101111101110111110111011111011101111101111011101111110001111 " ;

$_Num [ 25 ] = " 1000000111110111101111011110111101111011110000011111011111111101111111110111111111011111111000111111 " ;

$_Num [ 26 ] = " 1110001111110111011110111110111011111011101111101110111110111011111011101001101111011001111110001011 " ;

$_Num [ 27 ] = " 1000001111110111011111011101111101110111110000111111010111111101101111110110111111011101111000110011 " ;

$_Num [ 28 ] = " 1110000011110111101111011110111101111111111001111111111001111111111011110111101111011110111100000111 " ;

$_Num [ 29 ] = " 1000000011101101101111110111111111011111111101111111110111111111011111111101111111110111111110001111 " ;

$_Num [ 30 ] = " 1000100011110111011111011101111101110111110111011111011101111101110111110111011111011101111110001111 " ;

$_Num [ 31 ] = " 1000100011110111011111011101111101110111111010111111101011111110101111111010111111110111111111011111 " ;

$_Num [ 32 ] = " 1001010011110101011111010101111101010111110101011111001001111110101111111010111111101011111110101111 " ;

$_Num [ 33 ] = " 1000100011110111011111101011111110101111111101111111110111111110101111111010111111011101111000100011 " ;

$_Num [ 34 ] = " 1000100011110111011111011101111110101111111010111111110111111111011111111101111111110111111110001111 " ;

$_Num [ 35 ] = " 1100000011110111011111111101111111101111111110111111110111111111011111111011111111101110111100000011 " ;

// 输出图像文件头

echo chr ( 66 ) . chr ( 77 ) . chr ( 230 ) . chr ( 4 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 54 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 40 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 40 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 10 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 1 ) . chr ( 0 );

// 输出图像信息头

echo chr ( 24 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 176 ) . chr ( 4 ) . chr ( 0 ) . chr ( 0 ) . chr ( 18 ) . chr ( 11 ) . chr ( 0 ) . chr ( 0 ) . chr ( 18 ) . chr ( 11 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 ) . chr ( 0 );