How to generate image verification code in php_php skills-PHP Tutorial-php.cn

How to generate image verification code in php_php skills

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Release： 2016-05-16 19:54:14

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This article shares with you the method of generating image verification code in PHP for your reference. The specific content is as follows

First, randomly select a fixed number of characters from the specified character set, draw them on the canvas in an irregular way, then add some interference points and interference elements appropriately, and finally output the picture, and a new verification code will be Done.

The front-end code is as follows:

<!DOCTYPE html>
<html>
<head>
 <meta http-equiv="content-type" content="text/html;charset=utf-8">
 <title>This is a test!</title>
 <link rel="stylesheet" type="text/css" href="css/bootstrap.min.css">
</head>
<body>
 <form name="form">
  <input type="text" placeholder="账号"/><br/>
  <input type="password" placeholder="密码"/><br/>
  <input type="text" placeholder="验证码"/>
  <img id="verImg" src="libs/verification.php"/>
  <a href="#" class="change" onclick="changeVer()">点击刷新</a><br/>
  <input type="submit" value="登录"/>
 </form>
 <script type="text/javascript">
 //刷新验证码
 function changeVer(){
  document.getElementById("verImg").src="libs/verification.php&#63;tmp="+Math.random();
 }
 </script>
</body>
</html>

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The code for the php script file verification code is as follows:

<&#63;php
 
session_start();
//开启session记录验证码数据
 
vCode(4, 15);//设置验证码的字符个数和图片基础宽度
 
//vCode 字符数目，字体大小，图片宽度、高度
function vCode($num = 4, $size = 20, $width = 0, $height = 0) {
 
 !$width && $width = $num * $size * 4 / 5 + 15;
 !$height && $height = $size + 10;
 
 //设置验证码字符集合
 $str = "23456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVW";
 //保存获取的验证码
 $code = '';
 
 //随机选取字符
 for ($i = 0; $i < $num; $i++) {
  $code .= $str[mt_rand(0, strlen($str)-1)];
 }
 
 //创建验证码画布
 $im = imagecreatetruecolor($width, $height);
 
 //背景色
 $back_color = imagecolorallocate($im, mt_rand(0,100),mt_rand(0,100), mt_rand(0,100));
 
 //文本色
 $text_color = imagecolorallocate($im, mt_rand(100, 255), mt_rand(100, 255), mt_rand(100, 255));
 
 imagefilledrectangle($im, 0, 0, $width, $height, $back_color);
 
 
  // 画干扰线
 for($i = 0;$i < 5;$i++) {
  $font_color = imagecolorallocate($im, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
  imagearc($im, mt_rand(- $width, $width), mt_rand(- $height, $height), mt_rand(30, $width * 2), mt_rand(20, $height * 2), mt_rand(0, 360), mt_rand(0, 360), $font_color);
 }
 
  // 画干扰点
 for($i = 0;$i < 50;$i++) {
  $font_color = imagecolorallocate($im, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
  imagesetpixel($im, mt_rand(0, $width), mt_rand(0, $height), $font_color);
 }
 
 //随机旋转角度数组
 $array=array(5,4,3,2,1,0,-1,-2,-3,-4,-5);
 
  // 输出验证码
 // imagefttext(image, size, angle, x, y, color, fontfile, text)
 @imagefttext($im, $size , array_rand($array), 12, $size + 6, $text_color, 'c:\WINDOWS\Fonts\simsun.ttc', $code);
 $_SESSION["VerifyCode"]=$code;
 //no-cache在每次请求时都会访问服务器
 //max-age在请求1s后再次请求会再次访问服务器，must-revalidate则第一发送请求会访问服务器，之后不会再访问服务器
 // header("Cache-Control: max-age=1, s-maxage=1, no-cache, must-revalidate");
 header("Cache-Control: no-cache");
 header("Content-type: image/png;charset=gb2312");
 //将图片转化为png格式
 imagepng($im);
 imagedestroy($im);
}
&#63;>

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The above is the entire content of this article. I hope it will be helpful for everyone to learn PHP programming and learn to write PHP image verification codes