PHP draws website login home page picture verification code,
Almost all website login pages will have a verification code. The verification code is a security protection mechanism and is required when registering. Manual verification is used to prevent junk registration machines from registering a large number of user accounts to occupy server memory and paralyze the server.
The implementation of image verification code is very simple. 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 brand new verification code is completed.
Let me show you the generated verification code first:
Click to refresh:
If you are very satisfied with the effect, please continue reading below.
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="賬號"/><br/>
<input type="password" placeholder="密碼"/><br/>
<input type="text" placeholder="驗證碼"/>
<img id="verImg" src="libs/verification.php"/>
<a href="#" class="change" onclick="changeVer()">點擊刷新</a><br/>
<input type="submit" value="登錄"/>
</form>
<script type="text/javascript">
//刷新驗證碼
function changeVer(){
document.getElementById("verImg").src="libs/verification.php?tmp="+Math.random();
}
</script>
</body>
</html>
The code for the php script file verification code is as follows:
<?php
session_start();
//開啟session記錄驗證碼數(shù)據(jù)
vCode(4, 15);//設置驗證碼的字符個數(shù)和圖片基礎寬度
//vCode 字符數(shù)目,字體大小,圖片寬度、高度
function vCode($num = 4, $size = 20, $width = 0, $height = 0) {
!$width && $width = $num * $size * 4 / 5 + 15;
!$height && $height = $size + 10;
//設置驗證碼字符集合
$str = "23456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVW";
//保存獲取的驗證碼
$code = '';
//隨機選取字符
for ($i = 0; $i < $num; $i++) {
$code .= $str[mt_rand(0, strlen($str)-1)];
}
//創(chuàng)建驗證碼畫布
$im = imagecreatetruecolor($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, $back_color);
// 畫干擾線
for($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), $font_color);
}
// 畫干擾點
for($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);
}
//隨機旋轉角度數(shù)組
$array=array(5,4,3,2,1,0,-1,-2,-3,-4,-5);
// 輸出驗證碼
// imagefttext(image, size, angle, x, y, color, fontfile, text)
@imagefttext($im, $size , array_rand($array), 12, $size + 6, $text_color, 'c:\WINDOWS\Fonts\simsun.ttc', $code);
$_SESSION["VerifyCode"]=$code;
//no-cache在每次請求時都會訪問服務器
//max-age在請求1s后再次請求會再次訪問服務器,must-revalidate則第一發(fā)送請求會訪問服務器,之后不會再訪問服務器
// 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");
//將圖片轉化為png格式
imagepng($im);
imagedestroy($im);
}
?>
Okay, that’s all about the PHP image drawing verification that the editor introduced to you. I hope it will be helpful to you!
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