captcha.php

<?php

/* * ************************************************************ */
/* PhpCaptcha - A visual and audio CAPTCHA generation library

  Software License Agreement (BSD License)

  Copyright (C) 2005-2006, Edward Eliot.
  All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:

 * Redistributions of source code must retain the above copyright
  notice, this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright
  notice, this list of conditions and the following disclaimer in the
  documentation and/or other materials provided with the distribution.
 * Neither the name of Edward Eliot nor the names of its contributors 
  may be used to endorse or promote products derived from this software
  without specific prior written permission of Edward Eliot.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS" AND ANY
  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY
  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

  Last Updated:  18th April 2006 */
/* * ************************************************************ */

/* * ********************** Documentation *********************** */
/*

  Documentation is available at http://www.ejeliot.com/pages/2

 */
/* * ********************** Default Options ********************* */

// start a PHP session - this class uses sessions to store the generated 
// code. Comment out if you are calling already from your application
//session_start();
if (session_id() == '') {
    session_start();
}
// class defaults - change to effect globally

define('CAPTCHA_SESSION_ID', 'php_captcha');
define('CAPTCHA_WIDTH', 200); // max 500
define('CAPTCHA_HEIGHT', 50); // max 200
define('CAPTCHA_NUM_CHARS', 5);
define('CAPTCHA_NUM_LINES', 70);
define('CAPTCHA_CHAR_SHADOW', false);
define('CAPTCHA_OWNER_TEXT', '');
define('CAPTCHA_CHAR_SET', ''); // defaults to A-Z
define('CAPTCHA_CASE_INSENSITIVE', true);
define('CAPTCHA_BACKGROUND_IMAGES', '');
define('CAPTCHA_MIN_FONT_SIZE', 16);
define('CAPTCHA_MAX_FONT_SIZE', 25);
define('CAPTCHA_USE_COLOUR', false);
define('CAPTCHA_FILE_TYPE', 'jpeg');
define('CAPTCHA_FLITE_PATH', '/usr/bin/flite');
define('CAPTCHA_AUDIO_PATH', '/tmp/'); // must be writeable by PHP process

/* * ********************** End Default Options ********************* */

// don't edit below this line (unless you want to change the class!)

class captcha {

    protected $oImage;
    protected $aFonts;
    protected $iWidth;
    protected $iHeight;
    protected $iNumChars;
    protected $iNumLines;
    protected $iSpacing;
    protected $bCharShadow;
    protected $sOwnerText;
    protected $aCharSet;
    protected $bCaseInsensitive;
    public $vBackgroundImages;
    protected $iMinFontSize;
    protected $iMaxFontSize;
    protected $bUseColour;
    protected $sFileType;
    public $sCode = '';

    function captcha() {
        /*$this->config($aFonts = null, // array of TrueType fonts to use - specify full path
                $iWidth = CAPTCHA_WIDTH, // width of image
                $iHeight = CAPTCHA_HEIGHT // height of image)
        );*/
        
    }

    function config(
    $aFonts = null, // array of TrueType fonts to use - specify full path
            $iWidth = CAPTCHA_WIDTH, // width of image
            $iHeight = CAPTCHA_HEIGHT // height of image
    ) {
        // get parameters
        $this->aFonts = $aFonts;
        $this->SetNumChars(CAPTCHA_NUM_CHARS);
        $this->SetNumLines(CAPTCHA_NUM_LINES);
        $this->DisplayShadow(CAPTCHA_CHAR_SHADOW);
        $this->SetOwnerText(CAPTCHA_OWNER_TEXT);
        $this->SetCharSet(CAPTCHA_CHAR_SET);
        $this->CaseInsensitive(CAPTCHA_CASE_INSENSITIVE);
        $this->SetBackgroundImages(CAPTCHA_BACKGROUND_IMAGES);
        $this->SetMinFontSize(CAPTCHA_MIN_FONT_SIZE);
        $this->SetMaxFontSize(CAPTCHA_MAX_FONT_SIZE);
        $this->UseColour(CAPTCHA_USE_COLOUR);
        $this->SetFileType(CAPTCHA_FILE_TYPE);
        $this->SetWidth($iWidth);
        $this->SetHeight($iHeight);
        return $this;
    }

    function CalculateSpacing() {
        $this->iSpacing = (int) ($this->iWidth / $this->iNumChars);
        return $this;
    }

    function SetWidth($iWidth) {
        $this->iWidth = $iWidth;
        if ($this->iWidth > 500)
            $this->iWidth = 500; // to prevent perfomance impact
        $this->CalculateSpacing();
        return $this;
    }

    function SetHeight($iHeight) {
        $this->iHeight = $iHeight;
        if ($this->iHeight > 200)
            $this->iHeight = 200; // to prevent performance impact
        return $this;
    }

    function SetNumChars($iNumChars) {
        $this->iNumChars = $iNumChars;
        $this->CalculateSpacing();
        return $this;
    }

    function SetNumLines($iNumLines) {
        $this->iNumLines = $iNumLines;
        return $this;
    }

    function DisplayShadow($bCharShadow) {
        $this->bCharShadow = $bCharShadow;
        return $this;
    }

    function SetOwnerText($sOwnerText) {
        $this->sOwnerText = $sOwnerText;
        return $this;
    }

    function SetCharSet($vCharSet) {
        // check for input type
        if (is_array($vCharSet)) {
            $this->aCharSet = $vCharSet;
        } else {
            if ($vCharSet != '') {
                // split items on commas
                $aCharSet = explode(',', $vCharSet);

                // initialise array
                $this->aCharSet = array();

                // loop through items 
                foreach ($aCharSet as $sCurrentItem) {
                    // a range should have 3 characters, otherwise is normal character
                    if (strlen($sCurrentItem) == 3) {
                        // split on range character
                        $aRange = explode('-', $sCurrentItem);

                        // check for valid range
                        if (count($aRange) == 2 && $aRange[0] < $aRange[1]) {
                            // create array of characters from range
                            $aRange = range($aRange[0], $aRange[1]);

                            // add to charset array
                            $this->aCharSet = array_merge($this->aCharSet, $aRange);
                        }
                    } else {
                        $this->aCharSet[] = $sCurrentItem;
                    }
                }
            }
        }
        return $this;
    }

    function CaseInsensitive($bCaseInsensitive) {
        $this->bCaseInsensitive = $bCaseInsensitive;
        return $this;
    }

    function SetBackgroundImages($vBackgroundImages) {
        $this->vBackgroundImages = $vBackgroundImages;
        return $this;
    }

    function SetMinFontSize($iMinFontSize) {
        $this->iMinFontSize = $iMinFontSize;
        return $this;
    }

    function SetMaxFontSize($iMaxFontSize) {
        $this->iMaxFontSize = $iMaxFontSize;
        return $this;
    }

    function UseColour($bUseColour) {
        $this->bUseColour = $bUseColour;
        return $this;
    }

    function SetFileType($sFileType) {
        // check for valid file type
        if (in_array($sFileType, array('gif', 'png', 'jpeg'))) {
            $this->sFileType = $sFileType;
        } else {
            $this->sFileType = 'jpeg';
        }
        return $this;
    }

    function DrawLines() {
        for ($i = 0; $i < $this->iNumLines; $i++) {
            // allocate colour
            if ($this->bUseColour) {
                $iLineColour = imagecolorallocate($this->oImage, rand(100, 250), rand(100, 250), rand(100, 250));
            } else {
                $iRandColour = rand(100, 250);
                $iLineColour = imagecolorallocate($this->oImage, $iRandColour, $iRandColour, $iRandColour);
            }

            // draw line
            imageline($this->oImage, rand(0, $this->iWidth), rand(0, $this->iHeight), rand(0, $this->iWidth), rand(0, $this->iHeight), $iLineColour);
        }
        return $this;
    }

    function DrawOwnerText() {
        // allocate owner text colour
        $iBlack = imagecolorallocate($this->oImage, 0, 0, 0);
        // get height of selected font
        $iOwnerTextHeight = imagefontheight(2);
        // calculate overall height
        $iLineHeight = $this->iHeight - $iOwnerTextHeight - 4;

        // draw line above text to separate from CAPTCHA
        imageline($this->oImage, 0, $iLineHeight, $this->iWidth, $iLineHeight, $iBlack);

        // write owner text
        imagestring($this->oImage, 2, 3, $this->iHeight - $iOwnerTextHeight - 3, $this->sOwnerText, $iBlack);

        // reduce available height for drawing CAPTCHA
        $this->iHeight = $this->iHeight - $iOwnerTextHeight - 5;
        return $this;
    }

    function GenerateCode() {
        // reset code
        $this->sCode = '';

        // loop through and generate the code letter by letter
        for ($i = 0; $i < $this->iNumChars; $i++) {
            if (count($this->aCharSet) > 0) {
                // select random character and add to code string
                $this->sCode .= $this->aCharSet[array_rand($this->aCharSet)];
            } else {
                // select random character and add to code string
                $this->sCode .= chr(rand(65, 90));
            }
        }

        // save code in session variable
        if ($this->bCaseInsensitive) {
            $_SESSION[CAPTCHA_SESSION_ID] = strtoupper($this->sCode);
        } else {
            $_SESSION[CAPTCHA_SESSION_ID] = $this->sCode;
        }
        return $this;
    }

    function DrawCharacters() {
        // loop through and write out selected number of characters
        for ($i = 0; $i < strlen($this->sCode); $i++) {
            // select random font
            $sCurrentFont = $this->aFonts != null ? $this->aFonts[array_rand($this->aFonts)] : 'Arial';

            // select random colour
            if ($this->bUseColour) {
                $iTextColour = imagecolorallocate($this->oImage, rand(0, 100), rand(0, 100), rand(0, 100));

                if ($this->bCharShadow) {
                    // shadow colour
                    $iShadowColour = imagecolorallocate($this->oImage, rand(0, 100), rand(0, 100), rand(0, 100));
                }
            } else {
                $iRandColour = rand(0, 100);
                $iTextColour = imagecolorallocate($this->oImage, $iRandColour, $iRandColour, $iRandColour);

                if ($this->bCharShadow) {
                    // shadow colour
                    $iRandColour = rand(0, 100);
                    $iShadowColour = imagecolorallocate($this->oImage, $iRandColour, $iRandColour, $iRandColour);
                }
            }

            // select random font size
            $iFontSize = rand($this->iMinFontSize, $this->iMaxFontSize);

            // select random angle
            $iAngle = rand(-30, 30);

            // get dimensions of character in selected font and text size
            $aCharDetails = imageftbbox($iFontSize, $iAngle, $sCurrentFont, $this->sCode[$i], array());

            // calculate character starting coordinates
            $iX = $this->iSpacing / 4 + $i * $this->iSpacing;
            $iCharHeight = $aCharDetails[2] - $aCharDetails[5];
            $iY = $this->iHeight / 2 + $iCharHeight / 4;

            // write text to image
            imagefttext($this->oImage, $iFontSize, $iAngle, $iX, $iY, $iTextColour, $sCurrentFont, $this->sCode[$i], array());

            if ($this->bCharShadow) {
                $iOffsetAngle = rand(-30, 30);

                $iRandOffsetX = rand(-5, 5);
                $iRandOffsetY = rand(-5, 5);

                imagefttext($this->oImage, $iFontSize, $iOffsetAngle, $iX + $iRandOffsetX, $iY + $iRandOffsetY, $iShadowColour, $sCurrentFont, $this->sCode[$i], array());
            }
        }
        return $this;
    }

    function WriteFile($sFilename) {
        if ($sFilename == '') {
            // tell browser that data is jpeg
            header("Content-type: image/$this->sFileType");
        }

        switch ($this->sFileType) {
            case 'gif':
                $sFilename != '' ? imagegif($this->oImage, $sFilename) : imagegif($this->oImage);
                break;
            case 'png':
                $sFilename != '' ? imagepng($this->oImage, $sFilename) : imagepng($this->oImage);
                break;
            default:
                $sFilename != '' ? imagejpeg($this->oImage, $sFilename) : imagejpeg($this->oImage);
        }
        return $this;
    }

    function create($sFilename = '') {
        // check for required gd functions
        if (!function_exists('imagecreate') || !function_exists("image$this->sFileType") || ($this->vBackgroundImages != '' && !function_exists('imagecreatetruecolor'))) {
            return false;
        }

        // get background image if specified and copy to CAPTCHA
        if (is_array($this->vBackgroundImages) || $this->vBackgroundImages != '') {
            // create new image
            $this->oImage = imagecreatetruecolor($this->iWidth, $this->iHeight);

            // create background image
            if (is_array($this->vBackgroundImages)) {
                $iRandImage = array_rand($this->vBackgroundImages);
                $oBackgroundImage = imagecreatefromjpeg($this->vBackgroundImages[$iRandImage]);
            } else {
                $oBackgroundImage = imagecreatefromjpeg($this->vBackgroundImages);
            }

            // copy background image
            imagecopy($this->oImage, $oBackgroundImage, 0, 0, 0, 0, $this->iWidth, $this->iHeight);

            // free memory used to create background image
            imagedestroy($oBackgroundImage);
        } else {
            // create new image
            $this->oImage = imagecreate($this->iWidth, $this->iHeight);
        }

        // allocate white background colour
        imagecolorallocate($this->oImage, 255, 255, 255);

        // check for owner text
        if ($this->sOwnerText != '') {
            $this->DrawOwnerText();
        }

        // check for background image before drawing lines
        if (!is_array($this->vBackgroundImages) && $this->vBackgroundImages == '') {
            $this->DrawLines();
        }

        $this->GenerateCode();
        $this->DrawCharacters();

        // write out image to file or browser
        $this->WriteFile($sFilename);

        // free memory used in creating image
        imagedestroy($this->oImage);

        return true;
    }
	
	
	function get_code() {
		 return !empty($_SESSION[CAPTCHA_SESSION_ID]) ? $_SESSION[CAPTCHA_SESSION_ID] : false;
	}
	

    // call this method statically
    function Validate($sUserCode, $bCaseInsensitive = true) {
        if ($bCaseInsensitive) {
            $sUserCode = strtoupper($sUserCode);
        }

        if (get_code() && $sUserCode == get_code()) {
            // clear to prevent re-use
            unset($_SESSION[CAPTCHA_SESSION_ID]);

            return true;
        }

        return false;
    }

}



?>