PHP图形验证码生成代码与包括Ajax验证实例应用

       

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验证码:

        session_start ();
        header ( 'content-type: image/png' );
        //创建图片
        $im = imagecreate($x=130,$y=45 );
        $bg = imagecolorallocate($im,rand(50,200),rand(0,155),rand(0,155));

//第一次对 imagecolorallocate() 的调用会给基于调色板的图像填充背景色
        $fontcolor = imagecolorallocate ( $im, 255, 255, 255 );            

            //字体颜色
        $fontstyle = 'rock.ttf';                                           

                             //字体样式文件，这个文件是从我们

c:windows onts下的字体中随便选一个出来的，你们也可以替换其他的！
        //产生随机字符
        for($i = 0; $i < 4; $i ++) {
                $randasciinumarray         = array (rand(48,57),rand

(65,90));
                $randasciinum                 = $randasciinumarray [rand (

0, 1 )];
                $randstr                         = chr ( $randasciinum );
                imagettftext($im,30,rand(0,20)-rand(0,25),5+$i*30,rand

(30,35),$fontcolor,$fontstyle,$randstr);
                $authcode                        .= $randstr;
        }
        $_session['authcode']        = $authcode;
        //干扰线
        for ($i=0;$i<8;$i++){
                $linecolor        = imagecolorallocate($im,rand

(0,255),rand(0,255),rand(0,255));
                imageline ($im,rand(0,$x),0,rand(0,$x),$y,$linecolor);
        }
        //干扰点
        for ($i=0;$i<250;$i++){
                imagesetpixel($im,rand(0,$x),rand(0,$y),$fontcolor);
        }
        imagepng($im);
        imagedestroy($im);