<?/** * 验证码 * 2011/8/21 * kcj * */include "isLogin.php";//随机生成一个4位数字的验证码$num='';for($i=0;$i<4;$i++){$num.=dechex(rand(0,20)); //dechex函数是十进制转会二进制}session_start(); //开启session$_SESSION['yanzheng']=$num; //用session记住这个验证数字header("Content-type:image/PNG");$im=imagecreate(60,20); //创建一个画布$back=imagecolorallocate($im,rand(0,55),rand(0,20),rand(0,5));//创建一个背景颜色 (黑色)$gray=imagecolorallocate($im,rand(0,255),rand(0,200),rand(0,55)); //(白色)imagefill($im,0,0,$gray); //填充颜色$style=array($back,$back,$back,$back,$back,$gray,$gray,$gray,$gray,$gray); //生成数组imagesetstyle($im,$style); //设定画线风格$y1=rand(0,20);$y2=rand(0,20);$y3=rand(0,20);$y4=rand(0,20);imageline($im,0,$y1,60,$y3,IMG_COLOR_STYLED); //画一条线imageline($im,0,$y2,60,$y4,IMG_COLOR_STYLED);//在画布上随机生成大量黑点，起干扰作用for ($i=0;$i<80;$i++){imagesetpixel($im,rand(0,60),rand(0,20),$back);}$str=rand(3,8);for ($i=0;$i<4;$i++){$strp=rand(1,6);imagestring($im,6,$str,$strp,substr($num,$i,1),$back);$str+=rand(8,12);}ImagePNG($im);imagedestroy($im);?>
