<?php

 error_reporting ( 1 );
$font_file = "fonts/calibri.ttf";
$font_size =  18 ;
$keystring =  substr ( md5 ( mt_rand ()),  0 ,  3 );
$spacing =  9 ;
$width = ($font_size + $spacing) *  strlen ($keystring) + $spacing;
$height = $font_size + $spacing *  2 ;
$padding_top = $font_size + $spacing;
 session_start ();
$_SESSION["captcha_keystring"] = $keystring;
$img =  imagecreate ($width, $height);
$background =  imagecolorallocate ($img,  255 ,  255 ,  255 );
$color =  imagecolorallocate ($img,  0 ,  0 ,  0 );
$keystring =  str_split ( strtoupper ($keystring));
$padding_left = $spacing;
$half_spacing = $spacing /  2 ;
$half_font_size = $font_size /  2 ;
 for  ($i =  0 ; $i <  count ($keystring); ++$i) {
     imagettftext ($img, $font_size +  mt_rand (-$half_font_size, $half_font_size),  mt_rand (- 15 ,  15 ), $padding_left +  mt_rand (-$half_spacing, $half_spacing), $padding_top +  mt_rand (-$half_spacing, $half_spacing), $color, $font_file, $keystring[$i]);
    $padding_left += $font_size + $spacing;
}

$img2 =  imagecreate ($width, $height);

$rand1 =  mt_rand ( 750000 , 1200000 )/ 10000000 ;
$rand2 =  mt_rand ( 750000 , 1200000 )/ 10000000 ;
$rand3 =  mt_rand ( 750000 , 1200000 )/ 10000000 ;
$rand4 =  mt_rand ( 750000 , 1200000 )/ 10000000 ;

// phases
$rand5 =  mt_rand ( 0 , 31415926 )/ 10000000 ;
$rand6 =  mt_rand ( 0 , 31415926 )/ 10000000 ;
$rand7 =  mt_rand ( 0 , 31415926 )/ 10000000 ;
$rand8 =  mt_rand ( 0 , 31415926 )/ 10000000 ;

// amplitudes
$rand9 =  mt_rand ( 330 , 420 )/ 110 ;
$rand10 =  mt_rand ( 330 , 450 )/ 110 ;

$center = $width /  2 ;

//wave distortion
 for ($x =  0 ; $x < $width; ++$x) {
     for ($y =  0 ; $y < $height; ++$y) {
        $sx = $x + ( sin ($x * $rand1 + $rand5) +  sin ($y * $rand3 + $rand6)) * $rand9 - $width /  2  + $center +  1 ;
	$sy = $y + ( sin ($x * $rand2 + $rand7) +  sin ($y * $rand4 + $rand8)) * $rand10;
	 if  ($sx <  0  || $sy <  0  || $sx >= $width -  1  || $sy >= $height -  1 ) {
             continue ;
	}
         else  {
            $color =  imagecolorat ($img, $sx, $sy) & 0xFF;
            $color_x =  imagecolorat ($img, $sx +  1 , $sy) & 0xFF;
            $color_y =  imagecolorat ($img, $sx, $sy +  1 ) & 0xFF;
            $color_xy =  imagecolorat ($img, $sx +  1 , $sy +  1 ) & 0xFF;
	}
	 if ($color ==  255  && $color_x ==  255  && $color_y ==  255  && $color_xy ==  255 ){
             continue ;
        } 
         else   if ($color ==  0  && $color_x ==  0  && $color_y ==  0  && $color_xy ==  0 ) {
            $newred = $foreground_color[ 0 ];
            $newgreen = $foreground_color[ 1 ];
            $newblue = $foreground_color[ 2 ];
	}
         else  {
            $frsx = $sx -  floor ($sx);
	    $frsy = $sy -  floor ($sy);
	    $frsx1 =  1  - $frsx;
	    $frsy1 =  1  - $frsy;
	    $newcolor = $color * $frsx1 * $frsy1 + $color_x * $frsx * $frsy1 + $color_y * $frsx1 * $frsy + $color_xy * $frsx * $frsy;
             if ($newcolor >  255 ) {
                $newcolor =  255 ;
            }
	    $newcolor = $newcolor /  255 ;
	    $newcolor0 =  1  - $newcolor;
	    $newred = $newcolor0 * $foreground_color[ 0 ] + $newcolor * $background_color[ 0 ];
	    $newgreen = $newcolor0 * $foreground_color[ 1 ] + $newcolor * $background_color[ 1 ];
	    $newblue = $newcolor0 * $foreground_color[ 2 ] + $newcolor * $background_color[ 2 ];
	}
	 imagesetpixel ($img2, $x, $y,  imagecolorallocate ($img2, $newred, $newgreen, $newblue));
    }
}

 header ("Expires: Wed, 1 Jan 1997 00:00:00 GMT");
 header ("Last-Modified: " .  gmdate ("D, d M Y H:i:s") . " GMT");
 header ("Cache-Control: no-store, no-cache, must-revalidate");
 header ("Cache-Control: post-check=0, pre-check=0",  false );
 header ("Pragma: no-cache");
 header  ("Content-type: image/png");
 imagepng ($img2);
 imagedestroy ($img2);
        
?>