php简单验证码
<!--*@copyright(c)2011*@author:Ernest*@time:2011*@version:new--><?phpclass 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 < $this->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 <= 5; $i ++) { //循环画背景线$linecolor = imagecolorallocate ( $this->im, mt_rand ( 0, 255 ), mt_rand ( 0, 255 ), mt_rand ( 0, 255 ) );$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 <= 32; $i ++) { //循环画背景点,生成麻点效果$pointcolor = imagecolorallocate ( $this->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 ();?>