一个好用的PHP验证码类实例分享

分享一个好用的php验证码类，包括调用示例。
说明：
如果不适用指定的字体，那么就用imagestring()函数，如果需要遇到指定的字体，就要用到imagettftext()函数。字体的位置在C盘下Windows/Fonts.

参考了网上的php 生成验证码的方法，以及php 图片验证码和php 中文验证码的生成方法。用到了PHP GD库的相关知识。

1，生成验证码的类 VerificationCode.class.php

<?php  
    class VerificationCode{  
        private $charset="abcdefghjkmnpqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ23456789";  //随机因子  
        private $code;  //验证码  
        private $codelen=4; //验证码长度  
        private $width=110; //宽度  
        private $height=30; //高度  
        private $img;   //图像资源句柄  
        private $font;  //制定字体  
        private $fontSize=25;   //字体大小  
        private $fontColor; //字体颜色  
        public function __construct(){  
            $this->font="CALIBRIZ.TTF";  
        }  
        //生成验证码  
        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),$i*$x+mt_rand(1,5),$this->height/1.4,$this->fontColor,$this->font,$this->code[$i]);  // 3water.com
                //imagestring($this->img,5,$i*$x+mt_rand(1,5),5,$this->code[$i],$this->fontColor);  
            }  
        }  
        //生成线条、雪花  
        private function createDisturb(){  
            for ($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,$this->width),mt_rand(0,$this->width),mt_rand(0,$this->width),$color);  
            }  
            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);  
        }  
        public function showCode(){  
            $this->createBg();  
            $this->createCode();  
            $this->createDisturb();  
            $this->createFont();  
            $this->outPut();  
        }  
        //获取验证码  
        public function getCode(){  
            return strtolower($this->code);  
        }  
    }  
?>

code.php

<?php  
    session_start();  
    require_once 'VerificationCode.class.php';  
    $code=new VerificationCode();  
    $_SESSION['code']=$code->getCode();  
    $code->showCode();  
?>  
验证码:<input type="text" name="code" /><img src="code.php" onclick="javascript:this.src='code.php?time='+Math.random();" />