php实现验证码类

<?php
/* 
* [验证码类]
* @author: luochen[1102564499@qq.com]
* @Date:   2014-04-27 21:06:49
* @Last Modified time: 2014-04-28 20:02:03
*/
class Code{
	//验证码显示宽度
	private $width;
	//验证码显示高度
	private $height;
	//验证码字体大小
	private $fontSize;
	//验证码字体文件
	private $fontFile;
	//验证码字体颜色
	private $fontColor;
	//验证码背景颜色
	private $bgColor;
	//验证码长度
	private $codeLen;
	//验证码种子
	private $seek;
	//资源
	private $img;

	/**
	 * [__construct 初始化配置]
	 * @param [type] $width     [description]
	 * @param [type] $height    [description]
	 * @param [type] $fontSize  [description]
	 * @param [type] $codeLen   [description]
	 * @param [type] $fontFile  [description]
	 * @param [type] $fontColor [description]
	 * @param [type] $bgColor   [description]
	 */
	public function __construct($width = NULL,$height = NULL,$fontSize = NULL, $codeLen = NULL,$fontFile = NULL, $fontColor = NULL, $bgColor = NULL){

		$this->width = is_null($width) ? 200 : $width;
		$this->height = is_null($height) ? 50 : $height;
		$this->fontSize = is_null($fontSize) ? 24 : $fontSize;
		$this->codeLen = is_null($codeLen) ? 4 : $codeLen;
		$this->fontFile = is_null($fontFile) ? './font.ttf' : $fontFile;
		$this->fontColor = is_null($fontColor) ? '#000000' : $fontColor;
		$this->bgColor = is_null($bgColor) ? '#ffffff' : $bgColor;

		$this->seek = 'qwertyuiopasdfghjklzxcvbnm1234567890';

	}

	/**
	 * [show 显示验证码]
	 * @return [type] [description]
	 */
	public function show(){
		//发送头部
		header('Content-type:image/png');
		//创建背景
		$this->_create_bg();
		//画点
		$this->_create_point();
		//画线
		$this->_create_line();
		//写字
		$this->_create_font();

		//输出
		imagepng($this->img);
		//销毁资源
		imagedestroy($this->img);
	}

	/**
	 * [_create_font 写字]
	 * @return [type] [description]
	 */
	private function _create_font(){
		$str = '';
		for ($i=0; $i < $this->codeLen; $i++) { 
			//x
			$x = $this->width / $this->codeLen;
			$x = $x * $i + 15;
			//y
			$y = ($this->height + $this->fontSize) / 2;
			//转换字体颜色
			$fontColor = hexdec($this->fontColor);

			//随机字
			$seek = $this->seek;
			$text = $seek[mt_rand(0,strlen($seek) - 1)];

			imagettftext($this->img, $this->fontSize, mt_rand(-45,45), $x, $y, $fontColor, $this->fontFile, $text);

			$str .= $text;
		}
		//保存到session?

	}

	/**
	 * [_create_line 干扰线]
	 * @return [type] [description]
	 */
	private function _create_line(){

		for ($i=0; $i < 10; $i++) { 
			$color = imagecolorallocate($this->img, mt_rand(0,255), mt_rand(0,255), mt_rand(0,255));

			imageline($this->img, mt_rand(0,$this->width), mt_rand(0,$this->height), mt_rand(0,$this->width), mt_rand(0,$this->height), $color);
		}
	}
	/**
	 * [_create_point 干扰点]
	 * @return [type] [description]
	 */
	private function _create_point(){

		for ($i=0; $i < 200; $i++) { 
			$color = imagecolorallocate($this->img, mt_rand(0,255), mt_rand(0,255), mt_rand(0,255));

			imagesetpixel($this->img, mt_rand(0,$this->width), mt_rand(0,$this->height), $color);
		}


	}

	/**
	 * [_create_bg 创建背景]
	 * @return [type] [description]
	 */
	private function _create_bg(){
		//创建画布
		$img = imagecreatetruecolor($this->width, $this->height);
		//创建背景色
		$bgColor = hexdec($this->bgColor);
		//填充
		imagefill($img, 0, 0, $bgColor);
		//保存到类的属性里面
		$this->img = $img;
	}
}