PHP code to implement verification code

This article mainly shares with you the code for implementing verification code in PHP. In addition to js, ​​which can implement the verification code function, php can also be used. I hope it can help everyone.

<?php
header("content-type: image/png");  //这是一个图片格式
$imgwidth = 100;  //宽度
$imgheight = 40;  //高度
$font = &#39;NFLBRONC.TTF&#39;;  //字体
$img = imagecreatetruecolor($imgwidth,$imgheight); //创建一个真彩的图像
// 产生颜色
function color(){
	 global $img; // 声明全局变量
	 return imagecolorallocate($img,rand(0,200),rand(0,200),rand(0,200));  // 输出一个颜色
}
$white = imagecolorallocate($img, 255, 255, 255);
imagefill($img,0,0,$white); // 填充颜色
//生成随机验证码
$code = &#39;&#39;;
for($i=0;$i<4;$i++){
	if(rand(0,1000)%2==0){
		$code=chr(rand(97,122));
	}else{
		$code=rand(0,9);
	}
	$x = $i*20+10;
	$y = 30; 
	imageline($img,rand(0,20),rand(10,20),rand(20,120),rand(20,30),color());
	imagettftext($img, 20,0,$x,$y, color(),$font, $code);
}
////加入噪点干扰
for($i=0;$i<100;$i++) {
  imagesetpixel($img,rand(0, 100),rand(0, 100),color()); 
  imagesetpixel($img,rand(0, 100),rand(0, 100),color());
}
//输出验证码
imagepng($img);
//关闭
imagedestroy($img);
?>

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