/captcha.php

<?php



# KCAPTCHA PROJECT VERSION 1.2.6 (Modifided by Lauri)



# 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



session_start ();



class KCAPTCHA{



	private $keystring = '';

	

	// generates keystring and image

	public function __construct (){

		

		require('./kcaptcha_config.php');

		$fonts=array();

		$fontsdir_absolute=dirname(__FILE__).'/'.$fontsdir;

		if ($handle = opendir($fontsdir_absolute)) {

			while (false !== ($file = readdir($handle))) {

				if (preg_match('/\.png$/i', $file)) {

					$fonts[]=$fontsdir_absolute.'/'.$file;

				}

			}

		    closedir($handle);

		}	

	

		$alphabet_length=strlen($alphabet);

		

		do{

			// generating random keystring

			while(true){

				$this->keystring='';

				for($i=0;$i<$length;$i++){

					$this->keystring.=$allowed_symbols{mt_rand(0,strlen($allowed_symbols)-1)};

				}

				if(!preg_match('/cp|cb|ck|c6|c9|rn|rm|mm|co|do|cl|db|qp|qb|dp|ww/', $this->keystring)) break;

			}

		

			$font_file=$fonts[mt_rand(0, count($fonts)-1)];

			$font=imagecreatefrompng($font_file);

			imagealphablending($font, true);

			$fontfile_width=imagesx($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){

					$font_metrics[$alphabet{$symbol}]=array('start'=>$i);

					$reading_symbol=true;

					continue;

				}



				if($reading_symbol && $transparent){

					$font_metrics[$alphabet{$symbol}]['end']=$i;

					$reading_symbol=false;

					$symbol++;

					continue;

				}

			}



			$img=imagecreatetruecolor($width, $height);

			imagealphablending($img, true);

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

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



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



			// draw text

			$x=1;

			for($i=0;$i<$length;$i++){

				$m=$font_metrics[$this->keystring{$i}];



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



				if($no_spaces){

					$shift=0;

					if($i>0){

						$shift=10000;

						for($sy=7;$sy<$fontfile_height-20;$sy+=1){

							for($sx=$m['start']-1;$sx<$m['end'];$sx+=1){

				        		$rgb=imagecolorat($font, $sx, $sy);

				        		$opacity=$rgb>>24;

								if($opacity<127){

									$left=$sx-$m['start']+$x;

									$py=$sy+$y;

									if($py>$height) break;

									for($px=min($left,$width-1);$px>$left-12 && $px>=0;$px-=1){

						        		$color=imagecolorat($img, $px, $py) & 0xff;

										if($color+$opacity<190){

											if($shift>$left-$px){

												$shift=$left-$px;

											}

											break;

										}

									}

									break;

								}

							}

						}

						if($shift==10000){

							$shift=mt_rand(4,6);

						}



					}

				}else{

					$shift=1;

				}

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

				$x+=$m['end']-$m['start']-$shift;

			}

		}while($x>=$width-10); // while not fit in canvas



		$center=$x/2;



		// credits. To remove, see configuration file

		$img2=imagecreatetruecolor($width, $height+($show_credits?12:0));

		$foreground=imagecolorallocate($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, 0, $width-1, $height-1, $background);		

		imagefilledrectangle($img2, 0, $height, $width-1, $height+12, $foreground);

		$credits=empty($credits)?$_SERVER['HTTP_HOST']:$credits;

		imagestring($img2, 2, $width/2-imagefontwidth(2)*strlen($credits)/2, $height-2, $credits, $background);



		// 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(0,31415926)/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;



		//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: Mon, 26 Jul 1997 05:00:00 GMT'); 

		header('Cache-Control: no-store, no-cache, must-revalidate'); 

		header('Cache-Control: post-check=0, pre-check=0', FALSE); 

		header('Pragma: no-cache');

		

		if(function_exists("imagejpeg")){

			header("Content-Type: image/jpeg");

			imagejpeg($img2, null, $jpeg_quality);

		}else if(function_exists("imagegif")){

			header("Content-Type: image/gif");

			imagegif($img2);

		}else if(function_exists("imagepng")){

			header("Content-Type: image/x-png");

			imagepng($img2);

		}

	}



	// returns keystring

	public function getKeyString(){

		return $this->keystring;

	}

}



$oCaptcha = new KCAPTCHA;

$_SESSION['captcha'] = $oCaptcha->getKeyString ();