<?
# KCAPTCHA PROJECT VERSION 1.2.6

# Automatic test to tell computers and humans apart

# Copyright by Kruglov Sergei, 2006, 2007, 2008
# www.captcha.ru, www.kruglov.ru

# System requirements: PHP 4.0.6+ w/ GD

# KCAPTCHA is a free software. You can freely use it for building own site or software.
# If you use this software as a part of own sofware, you must leave copyright notices intact or add KCAPTCHA copyright notices to own.
# As a default configuration, KCAPTCHA has a small credits text at bottom of CAPTCHA image.
# You can remove it, but I would be pleased if you left it. ;)

# See kcaptcha_config.php for customization

// http://dle-news.ru

class kcaptcha {
    // ?????????? ????????? ??????? ---------

    var $alphabet = "0123456789abcdefghijklmnopqrstuvwxyz"; // ?? ?????????, ???? ?? ?? ???????? ???? ???????!
    // ?????????????????? ???? ?????? ?????????!

    // ????? ? ????????
    var $fontsdir = 'fonts';

    // ?????? ??????????? CAPTCHA (??????????? ?????????)
    var $width = 100;
    var $height = 50;

    // ????????? ???????????? ?????????? ????????, ???????? ?? 2
    var $fluctuation_amplitude = 2;

    // ??? ?????????? ???????????? ????? ?????? ??????? ????? ?????????
    var $no_spaces = true;

    // ???????? JPEG-??????????? CAPTCHA (??? ??????, ??? ???? ????????)
    var $jpeg_quality = 80; // ????????????, ????? ????????? 70-80

    var $keystring = ''; // ???????? ???????????? ??????

    // ???????, ???????????? ??? ????????? ???????????????? ??????????? CAPTCHA
    var $allowed_symbols = "23456789abcdeghkmnpqsuvxyz"; // ??????? ??? ??????? ???????? (o=0, 1=l, i=j, t=f)

    // ---------- ---------- ---------- ---------- ----------

    // ????????? ?????? ---------- ---------- -------
    function genstring($length = 4) {
        // ????? ?????? (?????????? ????????) CAPTCHA
        // ????????? ????? ? ???????? ?? $length_min ?? $length_max ????????????
        //$length = mt_rand( $this->length_min, $this->length_max );
        $this->length = $length;

        while (true) { // ??????????? ????, ???? ?? ?????????? ??????? ?????? =)
            $this->keystring = '';
            for ($i = 0; $i < $length ; $i++) {
                // ? ????? ????????? ? ?????? ?? 1 ?????????? ???????
                $this->keystring .= $this->allowed_symbols{ mt_rand( 0, strlen( $this->allowed_symbols ) -1 ) };
            }
            if (!preg_match( '/cp|cb|ck|c6|c9|rn|rm|co|do/', $this->keystring )) break;
        }
    }
    // ---------- ---------- ---------- ---------- ----------

    // ????????? ???????????
    function genimage() {

        // ????? ??????????? CAPTCHA (RGB, 0-255)
        $foreground_color = array( mt_rand( 0, 100 ), mt_rand( 0, 100 ), mt_rand( 0, 100 ) );
        $background_color = array( mt_rand( 200, 255 ), mt_rand( 200, 255 ), mt_rand( 200, 255 ) ); // ??? ?????? ???????

        $fonts = array();
        $fontsdir_absolute = dirname( __FILE__ ).'/'.$this->fontsdir; // ???? ? ????? ? ????????

        if ($handle = opendir( $fontsdir_absolute )) { // ??????? ?????? ? ??????? ?????? ? ???????????? ? ????????
            while (false !== ($file = readdir( $handle ))) {
                if (preg_match( '/\.png$/i', $file )) {
                    $fonts[] = $fontsdir_absolute.'/'.$file;
                }
            }
            closedir( $handle );
        }

        $alphabet_length = strlen( $this->alphabet );

        while (true) {
            $font_file = $fonts[mt_rand( 0, count( $fonts ) - 1 )]; // ???????? ????????? ???? ??????
            $font = imagecreatefrompng( $font_file );
            $black = imagecolorallocate( $font, 0, 0, 0 );
            $fontfile_width = imagesx( $font );
            $fontfile_height = imagesy( $font ) - 1;
            $font_metrics = array();
            $symbol = 0;
            $reading_symbol = false;

            // loading font
            for ($i = 0; $i < $fontfile_width && $symbol < $alphabet_length; $i++) {
                $transparent = (imagecolorat( $font, $i, 0 ) >> 24) == 127;

                if (!$reading_symbol && !$transparent) {
                    $font_metrics[$this->alphabet{$symbol}] = array( 'start' => $i );
                    $reading_symbol = true;
                    continue;
                }

                if ($reading_symbol && $transparent) {
                    $font_metrics[$this->alphabet{$symbol}]['end'] = $i;
                    $reading_symbol = false;
                    $symbol++;
                    continue;
                }
            }

            $img = imagecreatetruecolor( $this->width, $this->height );

            $white = imagecolorallocate( $img, 255, 255, 255 );
            $black = imagecolorallocate( $img, 0, 0, 0 );

            imagefilledrectangle( $img, 0, 0, $this->width - 1, $this->height - 1, $white );

            // draw text
            $x = 1;
            $shift = 0;

            for ($i = 0; $i < $this->length; $i++) {
                $m = $font_metrics[$this->keystring{$i}];

                $y = mt_rand( -$this->fluctuation_amplitude, $this->fluctuation_amplitude ) + ($this->height - $fontfile_height) / 2 + 2;


                if ($this->no_spaces) {
                    $shift = 0;
                    if ($i > 0) {
                        $shift = 1000;
                        for ($sy = 1; $sy < $fontfile_height - 15; $sy += 2) {
                            for ($sx = $m['start'] - 1; $sx < $m['end']; $sx++) {
                                $rgb = imagecolorat( $font, $sx, $sy );
                                $opacity = $rgb >> 24;
                                if ($opacity < 127) {
                                    $left = $sx - $m['start'] + $x;
                                    $py = $sy + $y;
                                    for ($px = min( $left, $this->width - 1 ); $px > $left - 15 && $px >= 0; $px--) {
                                        $color = imagecolorat( $img, $px, $py ) & 0xff;
                                        if ($color + $opacity < 190) {
                                            if ($shift > $left-$px) {
                                                $shift = $left - $px;
                                            }
                                            break;
                                        }
                                    }
                                    break;
                                }
                            }
                        }
                    }
                } else {
                    $shift = 1;
                }

                imagecopy( $img, $font, $x - $shift, $y, $m['start'], 1, $m['end'] - $m['start'], $fontfile_height );

                $x += $m['end'] - $m['start'] - $shift;
            }
            if ($x < $this->width - 10) break; // fit in canvas
        }
        $center = $x/2;

        $img2=imagecreatetruecolor($this->width, $this->height);
        $foreground=imagecolorallocate($img2, $foreground_color[0], $foreground_color[1], $foreground_color[2]);
        $background=imagecolorallocate($img2, $background_color[0], $background_color[1], $background_color[2]);
        imagefilledrectangle($img2, 0, $this->height, $this->width, $this->height+12, $foreground);


        // periods
        $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, 3141592 ) / 500000;
        $rand6 = mt_rand( 0, 3141592 ) / 500000;
        $rand7 = mt_rand( 0, 3141592 ) / 500000;
        $rand8 = mt_rand( 0, 3141592 ) / 500000;
        // amplitudes
        $rand9 = mt_rand( 330, 420 ) / 110;
        $rand10 = mt_rand(330, 450 ) / 110;

        //wave distortion
        for ($x = 0; $x < $this->width; $x++) {
            for ($y = 0; $y < $this->height; $y++) {
                $sx = $x + (sin( $x * $rand1 + $rand5 ) + sin( $y * $rand3 + $rand6 )) * $rand9 - $this->width / 2 + $center + 1;
                $sy = $y + (sin( $x * $rand2 + $rand7 ) + sin( $y * $rand4 + $rand8 )) * $rand10;

                if ($sx < 0 || $sy < 0 || $sx >= $this->width - 1 || $sy >= $this->height - 1) {
                    $color = 255;
                    $color_x = 255;
                    $color_y = 255;
                    $color_xy = 255;
                } 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 == 0 && $color_x == 0 && $color_y == 0 && $color_xy == 0) {
                    $newred = $foreground_color[0];
                    $newgreen = $foreground_color[1];
                    $newblue = $foreground_color[2];
                } else if ($color == 255 && $color_x == 255 && $color_y == 255 && $color_xy == 255) {
                    $newred = $background_color[0];
                    $newgreen = $background_color[1];
                    $newblue = $background_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 ) );
            }
        }

      # ?????
      imageline( $img2, 0, 0,  $this->width, 0, $foreground );
      imageline( $img2, 0, 0,  0, $this->height, $foreground );

      imageline( $img2, 0, $this->height-1,  $this->width, $this->height-1, $foreground );
      imageline( $img2, $this->width-1, 0,  $this->width-1, $this->height, $foreground);

        header( "Expires: Tue, 11 Jun 1985 05:00:00 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/jpeg" );
        imagejpeg($img2, null, $this->jpeg_quality);
    }
    // ---------- ---------- ---------- ---------- ----------
}
?>