PHP实现生成带背景的图形验证码功能

<?php    session_start ();    header ( 'Content-type: image/png' );    //创建图片    $im = imagecreate($x=130,$y=45 );    $bg = imagecolorallocate($im,rand(50,200),rand(0,155),rand(0,155)); //第一次对 imagecolorallocate() 的调用会给基于调色板的图像填充背景色    $fontColor = imageColorAllocate ( $im, 255, 255, 255 );  //字体颜色    $fontstyle = 'rock.ttf';          //字体样式，这个可以从c:windowsFonts文件夹下找到，我把它放到和authcode.php文件同一个目录，这里可以替换其他的字体样式    //产生随机字符    for($i = 0; $i < 4; $i ++) {        $randAsciiNumArray     = array (rand(48,57),rand(65,90));        $randAsciiNum         = $randAsciiNumArray [rand ( 0, 1 )];        $randStr             = chr ( $randAsciiNum );        imagettftext($im,30,rand(0,20)-rand(0,25),5+$i*30,rand(30,35),$fontColor,$fontstyle,$randStr);        $authcode            .= $randStr;    }    $_SESSION['authcode']    = $randFourStr;//用户和用户输入的验证码做比较    //干扰线    for ($i=0;$i<8;$i++){        $lineColor    = imagecolorallocate($im,rand(0,255),rand(0,255),rand(0,255));        imageline ($im,rand(0,$x),0,rand(0,$x),$y,$lineColor);    }    //干扰点    for ($i=0;$i<250;$i++){        imagesetpixel($im,rand(0,$x),rand(0,$y),$fontColor);    }    imagepng($im);    imagedestroy($im);?>

//首先开启sessionsession_start();//定义前台显示验证码长&宽$image_width = 120;$image_height = 40;$characters_on_image = 6;$font = './monofont.ttf';//The characters that can be used in the CAPTCHA code.//avoid confusing characters (l 1 and i for example)$possible_letters = '23456789bcdfghjkmnpqrstvwxyz';$random_dots = 10;$random_lines = 30;$captcha_text_color="0x142864";$captcha_noice_color = "0x142864";//定义要生成验证码的字符串$code = '';$i = 0;while ($i < $characters_on_image) {$code .= substr($possible_letters, mt_rand(0, strlen($possible_letters)-1), 1);$i++;}$font_size = $image_height * 0.75;$image = @imagecreate($image_width, $image_height);/* setting the background, text and noise colours here */$background_color = imagecolorallocate($image, 255, 255, 255);$arr_text_color = hexrgb($captcha_text_color);$text_color = imagecolorallocate($image, $arr_text_color['red'],    $arr_text_color['green'], $arr_text_color['blue']);$arr_noice_color = hexrgb($captcha_noice_color);$image_noise_color = imagecolorallocate($image, $arr_noice_color['red'],    $arr_noice_color['green'], $arr_noice_color['blue']);/* generating the dots randomly in background */for( $i=0; $i<$random_dots; $i++ ) {imagefilledellipse($image, mt_rand(0,$image_width), mt_rand(0,$image_height), 2, 3, $image_noise_color);}/* generating lines randomly in background of image */for( $i=0; $i<$random_lines; $i++ ) {imageline($image, mt_rand(0,$image_width), mt_rand(0,$image_height), mt_rand(0,$image_width), mt_rand(0,$image_height), $image_noise_color);}/* create a text box and add 6 letters code in it */$textbox = imagettfbbox($font_size, 0, $font, $code);$x = ($image_width - $textbox[4])/2;$y = ($image_height - $textbox[5])/2;imagettftext($image, $font_size, 0, $x, $y, $text_color, $font , $code);/* Show captcha image in the page html page */header('Content-Type: image/jpeg');// defining the image type to be shown in browser widowimagejpeg($image);//showing the imageimagedestroy($image);//destroying the image instance//设置session，做验证$_SESSION['6_letters_code'] = $code;function hexrgb ($hexstr){ $int = hexdec($hexstr); return array("red" => 0xFF & ($int >> 0x10),        "green" => 0xFF & ($int >> 0x8),        "blue" => 0xFF & $int);}

<?phpsession_start();if(isset($_REQUEST['Submit'])){  // code for check server side validation  if(emptyempty($_SESSION['6_letters_code'] ) ||    strcasecmp($_SESSION['6_letters_code'], $_POST['6_letters_code']) != 0)  {    $msg="您输入的验证码有误，请重新输入!";  }else{    echo "您输入的是正确的!";    // Captcha verification is Correct. Final Code Execute here!  }}?><style type="text/css">.table{  font-family:Arial, Helvetica, sans-serif;  font-size:12px;  color:#333;  background-color:#E4E4E4;}.table td{  background-color:#F8F8F8;}</style><form action="" method="post" name="form1" id="form1" > <table width="400" border="0" align="center" cellpadding="5" cellspacing="1"><?php if(isset($msg)){?>  <tr>   <td colspan="2" align="center" valign="top"><?php echo $msg;?></td>  </tr><?php } ?>  <tr>   <td align="right" valign="top"> 验证码Demo:</td>   <td><img src="captcha_code_file.php?rand=<?php echo rand(0,20);?>" id='captchaimg' onclick="refreshCaptcha();" ><br>    <label for='message'>请输入验证码:</label>    <br>    <input id="6_letters_code" name="6_letters_code" type="text">    <br>    如果看不到，请 <a href='javascript： refreshCaptcha();'>点我</a> 刷新一下!    </p></td>  </tr>  <tr>   <td>&nbsp;</td>   <td><input name="Submit" type="submit" onclick="return validate();" value="Submit"></td>  </tr> </table></form><script type='text/javascript'>//定义的刷新请求function refreshCaptcha(){  var img = document.images['captchaimg'];  img.src = img.src.substring(0,img.src.lastIndexOf("?"))+"?rand="+Math.random()*1000;}</script>

<?session_start();?><FORM METHOD=POST ACTION=""><input type=text name=number maxlength=4><img src="YanZhengMa.php?act=init"><INPUT TYPE="submit" name="sub"></FORM><?//检验校验码if(isset($HTTP_POST_VARS["sub"])):if($HTTP_POST_VARS["number"] != $HTTP_SESSION_VARS[login_check_number] || emptyempty($HTTP_POST_VARS["number"])){  echo "校验码不正确!" ;}else{  echo"验证码通过！";}endif;show_source('test.php');//以上本页的源码//以下是生成验证码的源码show_source('YanZhengMa.php');?><?phpsession_start();session_register("login_check_number");//昨晚看到了chianren上的验证码效果，就考虑了一下，用PHP的GD库完成了类似功能//先成生背景，再把生成的验证码放上去$img_height=120;  //先定义图片的长、宽$img_width=40;if($HTTP_GET_VARS["act"]== "init"){  //srand(microtime() * 100000);//PHP420后，srand不是必须的  for($Tmpa=0;$Tmpa<4;$Tmpa++){    $nmsg.=dechex(rand(0,15));  }//by sports98  $HTTP_SESSION_VARS[login_check_number] = $nmsg;  //$HTTP_SESSION_VARS[login_check_number] = strval(mt_rand("1111","9999"));  //生成4位的随机数，放入session中  //谁能做下补充，可以同时生成字母和数字啊？？----由sports98完成了  $aimg = imageCreate($img_height,$img_width);  //生成图片  ImageColorAllocate($aimg, 255,255,255);      //图片底色，ImageColorAllocate第1次定义颜色PHP就认为是底色了  $black = ImageColorAllocate($aimg, 0,0,0);    //定义需要的黑色  ImageRectangle($aimg,0,0,$img_height-1,$img_width-1,$black);//先成一黑色的矩形把图片包围  //下面该生成雪花背景了，其实就是在图片上生成一些符号  for ($i=1; $i<=100; $i++) {  //先用100个做测试    imageString($aimg,1,mt_rand(1,$img_height),mt_rand(1,$img_width),"*",imageColorAllocate($aimg,mt_rand(200,255),mt_rand(200,255),mt_rand(200,255)));    //哈，看到了吧，其实也不是雪花，就是生成＊号而已。为了使它们看起来"杂乱无章、5颜6色"，就得在1个1个生成它们的时候，让它们的位置、颜色，甚至大小都用随机数，rand()或mt_rand都可以完成。  }  //上面生成了背景，现在就该把已经生成的随机数放上来了。道理和上面差不多，随机数1个1个地放，同时让他们的位置、大小、颜色都用成随机数~~  //为了区别于背景，这里的颜色不超过200，上面的不小于200  for ($i=0;$i<strlen($HTTP_SESSION_VARS[login_check_number]);$i++){    imageString($aimg, mt_rand(3,5),$i*$img_height/4+mt_rand(1,10),mt_rand(1,$img_width/2), $HTTP_SESSION_VARS[login_check_number][$i],imageColorAllocate($aimg,mt_rand(0,100),mt_rand(0,150),mt_rand(0,200)));  }  Header("Content-type: image/png");  //告诉浏览器，下面的数据是图片，而不要按文字显示  ImagePng($aimg);          //生成png格式。。。嘿嘿效果蛮像回事的嘛。。。  ImageDestroy($aimg);}?>