将以下代码保存为:php-captcha.inc.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();
	   
	   // 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 PhpCaptcha {
	      var $oImage;
	      var $aFonts;
	      var $iWidth;
	      var $iHeight;
	      var $iNumChars;
	      var $iNumLines;
	      var $iSpacing;
	      var $bCharShadow;
	      var $sOwnerText;
	      var $aCharSet;
	      var $bCaseInsensitive;
	      var $vBackgroundImages;
	      var $iMinFontSize;
	      var $iMaxFontSize;
	      var $bUseColour;
	      var $sFileType;
	      var $sCode = '';
	      
	      function PhpCaptcha(
	         $aFonts, // 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);
	      }
	      
	      function CalculateSpacing() {
	         $this->iSpacing = (int)($this->iWidth / $this->iNumChars);
	      }
	      
	      function SetWidth($iWidth) {
	         $this->iWidth = $iWidth;
	         if ($this->iWidth > 500) $this->iWidth = 500; // to prevent perfomance impact
	         $this->CalculateSpacing();
	      }
	      
	      function SetHeight($iHeight) {
	         $this->iHeight = $iHeight;
	         if ($this->iHeight > 200) $this->iHeight = 200; // to prevent performance impact
	      }
	      
	      function SetNumChars($iNumChars) {
	         $this->iNumChars = $iNumChars;
	         $this->CalculateSpacing();
	      }
	      
	      function SetNumLines($iNumLines) {
	         $this->iNumLines = $iNumLines;
	      }
	      
	      function DisplayShadow($bCharShadow) {
	         $this->bCharShadow = $bCharShadow;
	      }
	      
	      function SetOwnerText($sOwnerText) {
	         $this->sOwnerText = $sOwnerText;
	      }
	      
	      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;
	                  }
	               }
	            }
	         }
	      }
	      
	      function CaseInsensitive($bCaseInsensitive) {
	         $this->bCaseInsensitive = $bCaseInsensitive;
	      }
	      
	      function SetBackgroundImages($vBackgroundImages) {
	         $this->vBackgroundImages = $vBackgroundImages;
	      }
	      
	      function SetMinFontSize($iMinFontSize) {
	         $this->iMinFontSize = $iMinFontSize;
	      }
	      
	      function SetMaxFontSize($iMaxFontSize) {
	         $this->iMaxFontSize = $iMaxFontSize;
	      }
	      
	      function UseColour($bUseColour) {
	         $this->bUseColour = $bUseColour;
	      }
	      
	      function SetFileType($sFileType) {
	         // check for valid file type
	         if (in_array($sFileType, array('gif', 'png', 'jpeg'))) {
	            $this->sFileType = $sFileType;
	         } else {
	            $this->sFileType = 'jpeg';
	         }
	      }
	      
	      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);
	         }
	      }
	      
	      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;
	      }
	      
	      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;
	         }
	      }
	      
	      function DrawCharacters() {
	         // loop through and write out selected number of characters
	         for ($i = 0; $i < strlen($this->sCode); $i++) {
	            // select random font
	            $sCurrentFont = $this->aFonts[array_rand($this->aFonts)];
	            
	            // 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());
	            }
	         }
	      }
	      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);
	         }
	      }
	      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($this->oImage);
	         return true;
	      }
	      // call this method statically
	      function Validate($sUserCode, $bCaseInsensitive = true) {
	         if ($bCaseInsensitive) {
	            $sUserCode = strtoupper($sUserCode);
	         }
	         if (!empty($_SESSION[CAPTCHA_SESSION_ID]) && $sUserCode == $_SESSION[CAPTCHA_SESSION_ID]) {
	            // clear to prevent re-use
	            unset($_SESSION[CAPTCHA_SESSION_ID]);
	            
	            return true;
	         }
	         
	         return false;
	      }
	   }
	   // this class will only work correctly if a visual CAPTCHA has been created first using PhpCaptcha
	   class AudioPhpCaptcha {
	      var $sFlitePath;
	      var $sAudioPath;
	      var $sCode;
	      function AudioPhpCaptcha(
	         $sFlitePath = CAPTCHA_FLITE_PATH, // path to flite binary
	         $sAudioPath = CAPTCHA_AUDIO_PATH // the location to temporarily store the generated audio CAPTCHA
	      ) {
	         $this->SetFlitePath($sFlitePath);
	         $this->SetAudioPath($sAudioPath);
	         // retrieve code if already set by previous instance of visual PhpCaptcha
	         if (isset($_SESSION[CAPTCHA_SESSION_ID])) {
	            $this->sCode = $_SESSION[CAPTCHA_SESSION_ID];
	         }
	      } 
	      function SetFlitePath($sFlitePath) {
	         $this->sFlitePath = $sFlitePath;
	      }
	      function SetAudioPath($sAudioPath) {
	         $this->sAudioPath = $sAudioPath;
	      }
	      function Mask($sText) {
	         $iLength = strlen($sText);
	         
	         // loop through characters in code and format
	         $sFormattedText = '';
	         for ($i = 0; $i < $iLength; $i++) {
	            // comma separate all but first and last characters
	            if ($i > 0 && $i < $iLength - 1) {
	               $sFormattedText .= ', ';
	            } elseif ($i == $iLength - 1) { // precede last character with "and"
	               $sFormattedText .= ' and ';
	            }
	            $sFormattedText .= $sText[$i];
	         }
	         $aPhrases = array(
	            "The %1\$s characters are as follows: %2\$s",
	            "%2\$s, are the %1\$s letters",
	            "Here are the %1\$s characters: %2\$s",
	            "%1\$s characters are: %2\$s",
	            "%1\$s letters: %2\$s"
	         );
	         
	         $iPhrase = array_rand($aPhrases);
	         
	         return sprintf($aPhrases[$iPhrase], $iLength, $sFormattedText);
	      }
	      function Create() {
	         $sText = $this->Mask($this->sCode);
	         $sFile = md5($this->sCode.time());
	         
	         // create file with flite
	         shell_exec("$this->sFlitePath -t \"$sText\" -o $this->sAudioPath$sFile.wav");
	         
	         // set headers
	         header('Content-type: audio/x-wav');
	         header("Content-Disposition: attachment;filename=$sFile.wav");
	         
	         // output to browser
	         echo file_get_contents("$this->sAudioPath$sFile.wav");
	         
	         // delete temporary file
	         @unlink("$this->sAudioPath$sFile.wav");
	      }
	   }
	   // example sub class
	   class PhpCaptchaColour extends PhpCaptcha {
	      function PhpCaptchaColour($aFonts, $iWidth = CAPTCHA_WIDTH, $iHeight = CAPTCHA_HEIGHT) {
	         // call parent constructor
	         parent::PhpCaptcha($aFonts, $iWidth, $iHeight);
	         
	         // set options
	         $this->UseColour(true);
	      }
	   }
	
		?>