php容易验证码

php简单验证码

<!--
*@copyright(c)2011
*@author:Ernest
*@time:2011
*@version:new
-->

<?php class VerifyImg {
	public $fontSize = 15; //定义字体大小
	public $length = 4; //定义字符串长度                        
	public $width = 70; //定义图片宽度
	public $height = 30; //定义图片高度
	public $im = null; //生成一张指定宽高的图片
	public $font = 'C:/Windows/Fonts/Arial.TTF';
	public $strNum = "";
	public function Build() {
		$strings = Array ('1', '2','3', '4', '5', '6', '7', 'a', 'b', 'c', 'd', 'e', 'f', 'h', 'i', 'j', 'k', 'm', 'n', 'p', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y' );
//		$strNum = "";
		$count = count ( $strings );
		for($i = 1; $i <= $this->length; $i ++) { //循环随机取字符生成字符串
			$strNum .= $strings [rand ( 0, $count - 1 )];
		}
		session_start ();
		$_SESSION ["verifycode"] = $strNum;
		$this->im = imagecreate ( $this->width, $this->height );
		$backgroundcolor = imagecolorallocate ( $this->im, 255, 255, 255 ); //生成背景色
		$frameColor = imageColorAllocate ( $this->im, 0, 255, 0 );
		for($i = 0; $i length; $i ++) {
			$charY = ($this->height + 9) / 2 + rand ( - 1, 1 ); //定义字符Y坐标
			$charX = $i * 15 + 8; //定义字符X坐标
			//            $text_color = imagecolorallocate($this->im, 255, 0, 0);                                                //生成字符颜色
			$text_color = imagecolorallocate ( $this->im, mt_rand ( 50, 255 ), mt_rand ( 50, 128 ), mt_rand ( 50, 200 ) );
			$angle = rand ( - 20, 20 ); //生成字符角度
			//写入字符
			imagettftext ( $this->im, $this->fontSize, $angle, $charX, $charY, $text_color, $this->font, $strNum [$i] );
		}
		for($i = 0; $i im, mt_rand ( 0, 255 ), mt_rand ( 0, 255 ), mt_rand ( 0, 255 ) );
			$linex = mt_rand ( 1, $this->width - 1 );
			$liney = mt_rand ( 1, $this->height - 1 );
			imageline ( $this->im, $linex, $liney, $linex + mt_rand ( 0, 4 ) - 2, $liney + mt_rand ( 0, 4 ) - 2, $linecolor );
		}
		for($i = 0; $i im, mt_rand ( 0, 255 ), mt_rand ( 0, 255 ), mt_rand ( 0, 255 ) );
			imagesetpixel ( $this->im, mt_rand ( 1, $this->width - 1 ), mt_rand ( 1, $this->height - 1 ), $pointcolor );
		}
		imagerectangle ( $this->im, 0, 0, $this->width - 1, $this->height - 1, $frameColor ); //画边框
		ob_clean ();
		header ( 'Content-type:image/png' );
		imagepng ( $this->im );
		imagedestroy ( $this->im );
	}
}
$img = new VerifyImg ();
$img->Build ();
?>