<?php
namespace verifycode;
use think\Session;
class Verify{
	private $charset;
	private $code;
	private $code_len;		//默认4
	private $img;
	private $width;			//默认80
	private $height;		//默认32
	private $font;			//字体路径
	private $font_size;		//默认20
	private $font_color;

	function __construct()
	{
		$this->font='./static/simhei.ttf';
		$this->code_len=4;
		$this->width=80;
		$this->height=32;
		$this->font_size=20;
		$this->charset='ABCDEFGHIJKLMNOPQRSTUVWXYZ';
	}

	//生成随机码  
	private function createCode()
	{
		$_len = strlen($this->charset)-1;
		for ($i=0;$i<$this->code_len;$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,238,238,238);
		imagefilledrectangle($this->img,0,$this->height,$this->width,0,$color);
	}

	//生成字体
	 private function createFont()
	{
		$_x = $this->width / $this->code_len;  
		for ($i=0;$i<$this->code_len;$i++)
		{
			$this->font_color = imagecolorallocate($this->img,mt_rand(0,156),mt_rand(0,156),mt_rand(0,156));  
			imagettftext($this->img,$this->font_size,0,$_x*$i+5,$this->height / 1.2,$this->font_color,$this->font,$this->code[$i]);  
		}
	}

	//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();
		$this->createFont();
		Session::set("img_verify",md5($this->getCode()));
		$this->outPut();
	}
		
	//获取验证码 
	public function getCode()
	{
		return strtolower($this->code);  
	}
}
?>