Free captcha script

<?php





function captcha($code)

{



/************************************************** Configuration **************************************************/



// Attention, le code est fait pour un code de 5 caractères (pas de minuscules)



$startOffset = 10;														// offset de départ sur l'image (en pixels)

$size_min = 35;															// taille minimum des caractères

$size_max = 60;															// taille maximum des caractères

$angle_min = 0;															// angle minimum d'inclinaison des caractères

$angle_max = 20;														// angle maximum d'inclinaison des caractères

$width = 201;															// largeur de l'image

$height = 71;															// hauteur de l'image

$addBlur = true;														// ajouter un floutage au code

$blurLevel = 1;															// niveau de floutage (entre 1 et 10 / 1 ou 2 conseillé après ça forme une bande autour des caractères)

$policePath =  dirname(__FILE__).DIRECTORY_SEPARATOR.'captcha.ttf';		// chemin de la police à utiliser



/********************************************* Ne rien toucher au dela *********************************************/



// création de l'image contenant le code

$_charsImgHandler = imagecreatetruecolor($width,$height) OR exit('please activate GD lib');

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

imagefill($_charsImgHandler, 0, 0,$white);

 

// on prépare et on copie le code en session et sur l'image

$i = -1;

$pos_x = $startOffset;

$cnt = strlen($code)-1;



while(++$i<=$cnt)

{

	$char = $code[$i];

	$color = imagecolorallocate($_charsImgHandler,mt_rand(0,200),mt_rand(0,200),mt_rand(0,200));

	$size =  mt_rand($size_min, $size_max);

	$pos_y = mt_rand($size, $height-3);

	imagettftext($_charsImgHandler, $size, mt_rand($angle_min,$angle_max), $pos_x, $pos_y, $color, $policePath, $char);

	$pos_x += 35;

}



/* on choisi et on applique l'effet brouillant */

switch(mt_rand(0,4))

{

	/* effet de dispersion */

	case 0:

		$x = -1;

		while(++$x<$width) 

		{

			$y = -1;

			while(++$y<$height) 

			{	

				$dispx = 1/(mt_rand(0,1) ? mt_rand(-2,-5) : mt_rand(2,5));

				$dispy = 1/(mt_rand(0,1) ? mt_rand(-2,-5) : mt_rand(2,5));

				

				if (($x + $dispx >= $width) || 

					($y + $dispy >= $height) || 

					($x + $dispx < 0) || 

					($y + $dispy < 0)) 

					continue;

			

				$oldcol = imagecolorat($_charsImgHandler, $x, $y);

				$newcol = imagecolorat($_charsImgHandler, $x + $dispx, $y + $dispy);

				imagesetpixel($_charsImgHandler, $x, $y, $newcol);

				imagesetpixel($_charsImgHandler, $x + $dispx, $y + $dispy, $oldcol);

			}

		}

	break;

	

	/* effet de cryptage */

	case 1:

		$ystop = $height-3;

		$y = -1;

	

		while(++$y<$ystop)

		{

			$j = $y+mt_rand()%3;

			$x = -1;

			

			while(++$x<$width)

			{

				$pixel = @imagecolorat($_charsImgHandler, $x, $y);

				$rgb = array( 'red' => ($pixel >> 16) & 0xFF, 'green' => ($pixel >> 8) & 0xFF, 'blue' => $pixel & 0xFF);

				$pixel = @imagecolorat($_charsImgHandler, $x, $j);

				$rgb2 = array( 'red' => ($pixel >> 16) & 0xFF, 'green' => ($pixel >> 8) & 0xFF, 'blue' => $pixel & 0xFF);

				

				$tmp = $rgb2['red'];

				$rgb2['red'] = $rgb['red'];

				$rgb['red'] = $tmp;

				

				$tmp = $rgb2['green'];

				$rgb2['green'] = $rgb['green'];

				$rgb['green'] = $tmp;

				

				$tmp = $rgb2['blue'];

				$rgb2['blue'] = $rgb['blue'];

				$rgb['blue'] = $tmp;

				

				imagesetpixel($_charsImgHandler,$x,$y,imagecolorallocate($_charsImgHandler,$rgb['red'],$rgb['green'],$rgb['blue']));

				imagesetpixel($_charsImgHandler,$x,$j,imagecolorallocate($_charsImgHandler,$rgb2['red'],$rgb2['green'],$rgb2['blue']));

			}

		}

	break;

	

	/* vagues horizontales */

	case 2:

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

		imagefill($_tempImg,0,0,$white);

		$up = true;

		$offset = 0;

		$stop = $width-3;

		

		for($y=0;$y<$height;++$y)

		{	

			if($up === true)

				$offset++;

					else



						$offset--;

			

			for($x=3;$x<$stop;++$x)

			{

				$color = @imagecolorat($_charsImgHandler, $x, $y);

				imagesetpixel($_tempImg,$x+$offset,$y, $color ? $color : $white);

			}

			

			if($offset === 3)

				$up = false;

					elseif(empty($offset))

						$up = true;

		}

		imagedestroy($_charsImgHandler);

		$_charsImgHandler = $_tempImg;

	break;

	

	/* vagues verticales */

	case 3:

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

		imagefill($_tempImg,0,0,$white);

		$up = true;

		$offset = 0;

		$stop = $height-3;

		

		for($x=0;$x<$width;++$x)

		{	

			if($up === true)

				$offset++;

					else

						$offset--;

			

			for($y=3;$y<$stop;++$y)

			{

				$color = @imagecolorat($_charsImgHandler, $x+$offset, $y);

				imagesetpixel($_tempImg,$x,$y, $color ? $color : $white);

			}

			

			if($offset === 3)

				$up = false;

					elseif(empty($offset))

						$up = true;

		}

		imagedestroy($_charsImgHandler);

		$_charsImgHandler = $_tempImg;

	break;

	

	/* effet fish eye */

	default:

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

		imageFill($_tempImg,0,0,$white);

		$xmid = (int)($width/2);

		$ymid = (int)($height/2);

		$start = (int)sqrt((float)($xmid*$xmid+$ymid*$ymid));

		

		$x = -1;

		while(++$x<$width) 

		{

			$y = -1;

			while(++$y<$height) 

			{

				$nx = $xmid-$x;

				$ny = $ymid-$y;

				$radius = sqrt((float)($nx*$nx+$ny*$ny));

				

				if($radius < $start) 

				{

					$angle = atan2((double)$ny,(double)$nx);

					$rnew = ($radius*$radius/$start);

					$nx = $xmid + (int)($rnew * cos($angle));

					$ny = $y;

					

					$nx = max(0,min($nx,$width));

					$ny = max(0,min($ny,$height));

					

					if(false === ($color = @imagecolorat($_charsImgHandler, $nx, $ny)))

						$color = $white;

				}

				else $color = $white;

			

				imagesetpixel($_tempImg, $x, $y, $color);

			}

		}

	

		imagedestroy($_charsImgHandler);

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

	

		for ($x=0;$x<$width;$x++)

			imagecopy($_charsImgHandler,$_tempImg, $x, 0, $width - $x - 1, 0, 1, $height);

	

		imagedestroy($_tempImg);

}



if($addBlur === true)

{

	if($blurLevel < 1)

		$blurLevel = 1;

			elseif($blurLevel > 10)

				$blurLevel = 10;

	

	$coeffs = array (

				array ( 1),

				array ( 1,  1), 

				array ( 1,  2,  1),

				array ( 1,  3,  3,   1),

				array ( 1,  4,  6,   4,   1),

				array ( 1,  5, 10,  10,   5,   1),

				array ( 1,  6, 15,  20,  15,   6,   1),

				array ( 1,  7, 21,  35,  35,  21,   7,   1),

				array ( 1,  8, 28,  56,  70,  56,  28,   8,   1),

				array ( 1,  9, 36,  84, 126, 126,  84,  36,   9,  1),

				array ( 1, 10, 45, 120, 210, 252, 210, 120,  45, 10,  1)

			);

	

	$sum = pow(2, $blurLevel);

	$temp1 = imagecreatetruecolor($width, $height);

	$temp2 = imagecreatetruecolor($width, $height);

	imagecopy($temp2,$_charsImgHandler,0,0,0,0,$width,$height);

	

	$y = -1;

	while(++$y<=$height)

	{

		$x = -1;

		while(++$x<=$width)

		{

			$sumr = 0; 

			$sumg = 0; 

			$sumb = 0;

			$k = -1;

			

			while(++$k<=$blurLevel)

			{

				$color = @imagecolorat($_charsImgHandler,($x-(($blurLevel)/2)+$k), $y);

				$sumr += (($color >> 16) & 0xFF) * $coeffs[$blurLevel][$k];

				$sumg += (($color >> 8) & 0xFF) * $coeffs[$blurLevel][$k];

				$sumb += ($color & 0xFF) * $coeffs[$blurLevel][$k];

			}

			

			$color = imagecolorallocate ($temp1,($sumr/$sum),($sumg/$sum),($sumb/$sum));

			imagesetpixel($temp1,$x,$y,$color);

		} 

	}

	

	imagedestroy($_charsImgHandler);

	$_charsImgHandler = $temp2;

	

	for($x=0;$x<$width;++$x) 

	{

		for($y=0;$y<$height;++$y) 

		{

			$sumr=0; $sumg=0; $sumb=0;

			

			for($k=0;$k<=$blurLevel;++$k) 

			{

				$color = @imagecolorat($temp1, $x,($y-(($blurLevel)/2)+$k));

				$sumr += (($color >> 16) & 0xFF) * $coeffs[$blurLevel][$k];

				$sumg += (($color >> 8) & 0xFF) * $coeffs[$blurLevel][$k];

				$sumb += ($color & 0xFF) * $coeffs[$blurLevel][$k];

			}

			

			$color = imagecolorallocate ($_charsImgHandler,($sumr/$sum),($sumg/$sum),($sumb/$sum));

			imagesetpixel($_charsImgHandler,$x,$y,$color);

		} 

	}

	

	imagedestroy($temp1);

}





// on rend transparent le fond de l'image contenant les caractères

imagecolortransparent($_charsImgHandler,$white);



// création image de fond

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

imagefill($_bgImgHandler, 0, 0,$white);



// choix de la couleur des lignes et du type de quadrillage

$line = imagecolorallocate($_bgImgHandler,mt_rand(200,230),mt_rand(200,230),mt_rand(200,230));

$lineType = mt_rand(0,11);



switch($lineType)

{

	/* Lignes et grilles "normales" */

	case 0:

	case 1:

	case 2:

		if($lineType !== 0) // ligne horizontales ou grille

		{

			for($y=0;$y<$height;$y+=5)

				imageline( $_bgImgHandler, 0, $y, $width, $y,$line);

		}

		if($lineType !== 1) // ligne verticales ou grille

		{

			for($y=0;$y<$width;$y+=5)

				imageline( $_bgImgHandler, $y, 0, $y, $width, $line);

		}

	break;	

	

	/* éventails */

	case 3:

	case 4:

	case 5:

		if($lineType !== 3) // eventail horizontal ou en grille

		{

			for($y=0,$z=0; $y<$width; ++$y,$z+=5)

				imageline( $_bgImgHandler, $width*2, 0, 0, $z, $line);

		}

		if($lineType !== 4) // eventail vertical ou en grille

		{

			for($y=0,$z=0; $y<$height; ++$y,$z+=5)

				imageline( $_bgImgHandler, 0, $width, $z, 0, $line);

		}	

	break;

	

	/* effet "matrix" */

	case 6: 

		for($x=0;$x<$width;$x+=mt_rand(1,4))

		{

			for($y=0;$y<$height;$y+=mt_rand(1,4))

				imagesetpixel( $_charsImgHandler, $x, $y, $line);

		}

	break;

	

	/* grille de points */

	case 7: 

		for($x=0;$x<$width;$x+=2)

		{

			for($y=0;$y<$height;$y+=2)

				imagesetpixel( $_charsImgHandler, $x, $y, $line);

		}

	break;

	

	/* autre grille de points */

	case 8: 

		for($x=0;$x<$width;$x+=3)

		{

			for($y=0;$y<$height;$y+=2)

				imagesetpixel( $_charsImgHandler, $x, $y, $line);

		}

	break;

	

	/* vaguelettes horizontales */

	case 9: 

		$up = true;

		$offset = 0;

		

		for($y=0;$y<$height;$y+=5)

		{	

			for($x=0;$x<$width;++$x)

			{

				if($up === true)

					$offset++;

						else

							$offset--;

			

				imagesetpixel( $_bgImgHandler, $x, $y+$offset, $line);

			

				if($offset === 3)

					$up = false;

						elseif(empty($offset))

							$up = true;

			}

		}

	break;

	

	/* vaguelettes verticales */

	case 10: 

		$up = true;

		$offset = 0;

		

		for($x=0;$x<$width;$x+=5)

		{	

			for($y=0;$y<$height;++$y)

			{

				if($up === true)

					$offset++;

						else

							$offset--;

				

				imagesetpixel( $_bgImgHandler, $x+$offset, $y, $line);

				

				if($offset === 3)

					$up = false;

						elseif(empty($offset))

							$up = true;

			}

		}

	break;

	

	/* grille irrégulière */

	default: 

		for($y=0;$y<$height;$y+=mt_rand(2,5))

			imageline( $_bgImgHandler, 0, $y, $width, $y,$line);

	

		for($y=0;$y<$width;$y+=mt_rand(2,5))

			imageline( $_bgImgHandler, $y, 0, $y, $width, $line);

}



// fusion du code et du fond

imagecopymerge($_bgImgHandler, $_charsImgHandler, 0, 0, 0, 0, $width, $height,100);

imagedestroy($_charsImgHandler);



// on affiche

header('Pragma: no-cache');

header('Last-Modified: '.gmdate('D, d M Y H:i:s').' GMT');

header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');

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

header('Cache-Control: private',false);

header ('Content-type: image/gif');

imagegif($_bgImgHandler);



}





?>