PHP验证码

设计一个验证码类，在需要的时候可以随时调用

验证码类，保存为ValidateCode.class.php

 <?php
 //验证码类
 session_start();
 class ValidateCode {
  private $charset = 'abcdefghkmnprstuvwxyzABCDEFGHKMNPRSTUVWXYZ23456789';//随机因子
  private $code;//验证码
  private $codelen = 4;//验证码长度
  private $width = 130;//宽度
  private $height = 50;//高度
  private $img;//图形资源句柄
  private $font;//指定的字体
  private $fontsize = 20;//指定字体大小
  private $fontcolor;//指定字体颜色
  //构造方法初始化
  public function __construct() {
   $this->font = './latha.ttf';//注意字体路径要写对，否则显示不了图片
  }
  //生成随机码
  private function createCode() {
   $_len = strlen($this->charset)-1;
   for ($i=0;$i<$this->codelen;$i++) {
    $this->code .= $this->charset[mt_rand(0,$_len)];
   }
  }
  //生成背景
  private function createBg() {
   $this->img = imagecreatetruecolor($this->width, $this->height);
   $color = imagecolorallocate($this->img, mt_rand(157,255), mt_rand(157,255), mt_rand(157,255));
   imagefilledrectangle($this->img,0,$this->height,$this->width,0,$color);
  }
  //生成文字
  private function createFont() {
   $_x = $this->width / $this->codelen;
   for ($i=0;$i<$this->codelen;$i++) {
    $this->fontcolor = imagecolorallocate($this->img,mt_rand(0,156),mt_rand(0,156),mt_rand(0,156));
    imagettftext($this->img,$this->fontsize,mt_rand(-30,30),$_x*$i+mt_rand(1,5),$this->height / 1.4,$this->fontcolor,$this->font,$this->code[$i]);
   }
  }
  //生成线条、雪花
  private function createLine() {
   //线条
   for ($i=0;$i<6;$i++) {
    $color = imagecolorallocate($this->img,mt_rand(0,156),mt_rand(0,156),mt_rand(0,156));
    imageline($this->img,mt_rand(0,$this->width),mt_rand(0,$this->height),mt_rand(0,$this->width),mt_rand(0,$this->height),$color);
   }
   //雪花
   for ($i=0;$i<100;$i++) {
    $color = imagecolorallocate($this->img,mt_rand(200,255),mt_rand(200,255),mt_rand(200,255));
    imagestring($this->img,mt_rand(1,5),mt_rand(0,$this->width),mt_rand(0,$this->height),'*',$color);
   }
  }
  //输出
  private function outPut() {
  header('Content-type:image/png');
   imagepng($this->img);
   imagedestroy($this->img);
  }
  //对外生成
  public function doimg() {
   $this->createBg();
   $this->createCode();
   $this->createLine();
   $this->createFont();
   $this->outPut();
  }
  //获取验证码
  public function getCode() {
   return strtolower($this->code);
  }
 }

注意：第16行中，要修改字体的路径，否则字体图片无法显示

实现，保存为captcha.php

 session_start();
 require './ValidateCode.class.php';  //先把类包含进来，实际路径根据实际情况进行修改。
 $_vc = new ValidateCode();  //实例化一个对象
 $_vc->doimg();
 $_SESSION['authnum_session'] = $_vc->getCode();//验证码保存到SESSION中

页面使用

<img  title="点击刷新" src="./captcha.php" align="absbottom" onclick="this.src='captcha.php?'+Math.random();"></img>

转载自：一个漂亮的php验证码类(分享)