Methods and examples of generating verification codes in PHP

Since registration codes are often used during registration to prevent malicious registration of machines, here I publish a basic image that generates a picture verification code. It is very simple. Friends in need can refer to the

image. func.php

<?php 
require_once(&#39;string.func.php&#39;);
 
 function verifyImage( $type=1,$length=4,$pixel=0,$line=0,$sess_name="verify"){ 
 
  session_start();
  /*定义长度和宽度*/
$width=80;
$height=30;
/* 创建画布*/
$image=imagecreatetruecolor($width, $height);
 
/*本函数用来匹配图形的颜色，供其它绘图函数使用。参数 image 表示图形的 handle。参数 red、green、blue 是色彩三原色，其值从 0 至 255....我在此定义黑色和白色*/
$white=imagecolorallocate($image, 255, 255, 255);
$black=imagecolorallocate($image,0,0,0);
 
/*本函数将图片的封闭长方形区域着色。参数 x1、y1 及 x2、y2 分别为矩形对角线的坐标。参数 col 表示欲涂上的颜色*/
imagefilledrectangle($image, 1, 1, $width-2, $height-2, $white);
 
/*buildRandomString函数用来生成一个验证码*/
$chars=buildRandomString($type,$length);
 
/*将验证码给session以便用来判断用户输入是否正确*/
$_SESSION[$sess_name]=$chars;
 
/*定义字体库*/
$fontfiles=array(&#39;msyh.ttf&#39;,&#39;msyhbd.ttf&#39;,&#39;simsun.ttc&#39;,&#39;SIMYOU.TTF&#39;,&#39;STHUPO.TTF&#39;,&#39;STKAITI.TTF&#39;,&#39;STLITI.TTF&#39;);
 
 
/*用循环来将验证码一个一个的写入图片中*/
for($i=0;$i<$length;$i++)
{
  $size=mt_rand(14,18);
  $angle=mt_rand(-15,15);
 
  /*验证码的横坐标与纵坐标*/
  $x=5+$i*$size;
  $y=mt_rand(20,26);
 
  $color=imagecolorallocate($image,mt_rand(50,190),mt_rand(50,200),mt_rand(50,90));
  $fontfile="../font/".$fontfiles[mt_rand(0,count($fontfiles)-1)];
  $text=substr($chars,$i,1);
 
  /*本函数将 TTF (TrueType Fonts) 字型文字写入图片*/
 imagettftext($image, $size, $angle, $x, $y, $color, $fontfile, $text);
}
if($pixel)
{
for($i=0;$i<50;$i++)
{
  /*本函数可在图片上绘出一点。参数 x、y 为欲绘点的坐标，参数 col 表示该点的颜色*/
  imagesetpixel($image, mt_rand(0,$width-1), mt_rand(0,$height-1), $black);
}}
if($line)
{
  for($i=0;$i<10;$i++)
  {
  $color=imagecolorallocate($image,mt_rand(50,90),mt_rand(50,200),mt_rand(50,90));
  /*画线段*/
  imageline($image, mt_rand(0,$width-1), mt_rand(0,$height-1), mt_rand(0,$width-1), mt_rand(0,$height-1), $color);
}
}
/*以gif形式输出*/
header("content-type:image/gif");
/*建立GIF图 并输出到网页*/
imagegif($image);
/*释放与 image 关联的内存*/
imagedestroy($image);
}

string.func.php

<?php 
 
function buildRandomString($type=1,$length=4){
 
if($type==1)
{
  /*join函数把数组转换为字符串。。join() 函数是 implode() 函数的别名*/
  $chars=join("",range(0,9));
}elseif ($type==2) {
  /*array_merge函数合并数组*/
  $chars=join("",array_merge(range("a","z"),range("A","Z")));
}elseif($type==3)
{
  $chars=join("",array_merge(range("a","z"),range("A","Z"),range(0,9)));
}
 
if($length>strlen($chars))
{
  exit("字符串长度不够");
}
/*打乱字符串*/
$chars=str_shuffle($chars);
return substr($chars,0,$length);
 
}
 ?>

Summary: The above is the entire content of this article, I hope it will be helpful to everyone's study.

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