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Use GD library to do verification code in php, phpgd library verification code_PHP tutorial



Use GD library to do verification code in php, phpgd library verification code_PHP tutorial
Jul 12, 2016 am 08:55 AM
php
wamp
Verification code
Use GD library for verification code in php, phpgd library verification code
<?php require_once 'string.func.php'; //通过GD库做验证码 /** *添加验证文字 * @param int $type * @param int $length */ function buildRandomString($type=1,$length=4){ $row=''; if($type==1){ $row=join('',range(0, 9)); }else if($type==2){ $row=join('', array_merge(range('a','z'),range('A', 'Z'))); }else if($type==3){ $row=join('', array_merge(range('a','z'),range('A', 'Z'),range(0, 9))); }; $row=str_shuffle($row); $row=substr($row,0,$length); return $row; } /** * 生成缩略图 * @param int $type //包含数字或者英文 * @param int $length 多少个字符 * @param int $pixel 干扰小点的密度 * @param int $dst_h 干扰线的密度 * @param string //验证码在$_SESSION中的名字 */ function verifyImage($type=1,$length=4,$pixel=0,$line=0,$sess_name = "verify"){ //session_start(); //创建画布 $width = 100; $height = 40; $image = imagecreatetruecolor ( $width, $height ); $white = imagecolorallocate ( $image, 255, 255, 255 ); $black = imagecolorallocate ( $image, 0, 0, 0 ); //用填充矩形填充画布 imagefilledrectangle ( $image, 1, 1, $width - 2, $height - 2, $white ); $chars = buildRandomString ( $type, $length ); $_SESSION [$sess_name] = $chars; //$fontfiles = array ("MSYH.TTF", "MSYHBD.TTF", "SIMLI.TTF", "SIMSUN.TTC", "SIMYOU.TTF", "STZHONGS.TTF" ); $fontfiles = array ("SIMKAI.TTF" ); //由于字体文件比较大,就只保留一个字体,如果有需要的同学可以自己添加字体,字体在你的电脑中的fonts文件夹里有,直接运行输入fonts就能看到相应字体 for($i = 0; $i < $length; $i ++) { $size = mt_rand ( 14, 18 ); $angle = mt_rand ( - 15, 15 ); $x = 5 + $i * $size; $y = mt_rand ( 20, 26 ); $fontfile = "../fonts/" . $fontfiles [mt_rand ( 0, count ( $fontfiles ) - 1 )]; $color = imagecolorallocate ( $image, mt_rand ( 50, 90 ), mt_rand ( 80, 200 ), mt_rand ( 90, 180 ) ); $text = substr ( $chars, $i, 1 ); imagettftext ( $image, $size, $angle, $x, $y, $color, $fontfile, $text ); } if ($pixel) { for($i = 0; $i < 50; $i ++) { imagesetpixel ( $image, mt_rand ( 0, $width - 1 ), mt_rand ( 0, $height - 1 ), $black ); } } if ($line) { for($i = 1; $i < $line; $i ++) { $color = imagecolorallocate ( $image, mt_rand ( 50, 90 ), mt_rand ( 80, 200 ), mt_rand ( 90, 180 ) ); imageline ( $image, mt_rand ( 0, $width - 1 ), mt_rand ( 0, $height - 1 ), mt_rand ( 0, $width - 1 ), mt_rand ( 0, $height - 1 ), $color ); } } header ( "content-type:image/gif" ); imagegif ( $image ); imagedestroy ( $image ); }
Copy after login
Main points:
1. If session_start() is not declared before; then it needs to be declared;
2. Fonts can be downloaded to your own defined fonts folder by entering fonts in cmf;
3. $_SESSION [$sess_name] can obtain the verification code entered by the user through $_POST for comparison.
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