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(hào)"/><br/>
<input type="password" placeholder="密碼"/><br/>
<input type="text" placeholder="驗(yàn)證碼"/>
<img id="verImg" src="libs/verification.php"/>
<a href="#" class="change" onclick="changeVer()">點(diǎn)擊刷新</a><br/>
<input type="submit" value="登錄"/>
</form>
<script type="text/javascript">
//刷新驗(yàn)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(kāi)啟session記錄驗(yàn)證碼數(shù)據(jù)
vCode(4, 15);//設(shè)置驗(yàn)證碼的字符個(gè)數(shù)和圖片基礎(chǔ)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(shè)置驗(yàn)證碼字符集合
$str = "23456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVW";
//保存獲取的驗(yàn)證碼
$code = '';
//隨機(jī)選取字符
for ($i = 0; $i < $num; $i++) {
$code .= $str[mt_rand(0, strlen($str)-1)];
}
//創(chuàng)建驗(yàn)證碼畫(huà)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, $back_color);
// 畫(huà)干擾線
for($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), $font_color);
}
// 畫(huà)干擾點(diǎn)
for($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(jī)旋轉(zhuǎn)角度數(shù)組
$array=array(5,4,3,2,1,0,-1,-2,-3,-4,-5);
// 輸出驗(yàn)證碼
// imagefttext(image, size, angle, x, y, color, fontfile, text)
@imagefttext($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(qǐng)求時(shí)都會(huì)訪問(wèn)服務(wù)器
//max-age在請(qǐng)求1s后再次請(qǐng)求會(huì)再次訪問(wèn)服務(wù)器，must-revalidate則第一發(fā)送請(qǐng)求會(huì)訪問(wèn)服務(wù)器，之后不會(huì)再訪問(wèn)服務(wù)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(zhuǎn)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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