php网页生成验证码实现程序

首先在表单页面展现之前，生成一副图片，并添加上一些干扰像素或线段（防止OCR程序自动识别） 再由PHP程序自动生成随机的待验证的一串数字和字母组合的字符， 调用imagettftext()函数画到图片中， 并把这串字符保存到Session级变量中。

<script>ec(2);</script>

完整实例

自动检测背景和字体，并随机选取背景图片中的一块范围，随机使用字体，显示验证字符串时随机显示字体大小，字符间距，字符颜色等

代码如下

复制代码

/** * Class for Validate image * @author  zcs * @version 1.0-20090828 */ session_start(); class validimg { //背景图片目录 var $backgroundpath = ‘validbg’; //生成验证码宽度 var $width =’80′; //生成验证码高度 var $height =’25′; //背景 var $background; //验证文本 var $text=’abcd’; //字体目录 var $fontpath = ‘validbg’; //字体 var $font=’simhei.ttf’; //字体宽度 var $font_width = ’20′; function validimg($text) { $this->text = $text; //随机选取一个背景文件 $bgdir =  @dir($this->backgroundpath); while(false !== ($image = $bgdir ->read())) { if($image != ‘.’ && $image != ‘..’ && $this->checktype($image) != false) { $backgroundarr[] = $image; } } $bgdir->close(); //随机选取一个字体文件 $fonts =  @dir($this->fontpath); while(false !== ($font = $fonts ->read())) { if($font != ‘.’ && $font != ‘..’ && $this->checktype($font,’FONT’) != false) { $fontsarr[] = $font; } } $fonts->close(); $this->font = $fontsarr[array_rand($fontsarr,1)]; $this->background = $backgroundarr[array_rand($backgroundarr,1)]; $this->output(); } //创建背景图像handdle function createbackground() { switch ($this->checktype($this->background)) { case ‘jpg’: $bghanddle = @imagecreatefromjpeg( $this->backgroundpath.’/’.$this->background); break; case ‘gif’: $bghanddle = @imagecreatefromgif( $this->backgroundpath.’/’.$this->background); break; case ‘png’: $bghanddle = @imagecreatefrompng( $this->backgroundpath.’/’.$this->background); break; default: } return $bghanddle; } //检查文件类型 function checktype( $image,$type = ‘IMAGE’) { $ext = substr( $image, strrpos($image,’.')+1); if($type == ‘IMAGE’) { if ($ext == ‘jpg’ || $ext ==’gif’ || $ext ==’png’) return $ext; else return false; }else if($type == ‘FONT’) { if ($ext == ‘ttf’) return $ext; else return false; } } //输出 function output() { header(“content-type:image/png;”); //生成图像 $img = @imagecreatetruecolor( $this->width,$this->height); $bghanddle = $this->createbackground(); //从背景图像随机位置载入一块作为背景 if($bghanddle) { $randx=rand(0,(imagesx($bghanddle) – $this->width)); $randy=rand(0,(imagesy($bghanddle) – $this->height)); } imagecopy($img,$bghanddle,0,0,$randx,$randy,$this->width,$this->height); //随机选择角度 字体大小 坐标输出文字 for($i=0;$itext);$i++) { $angle = rand(-30,30); $fontsize = rand(15,20); $x = rand($this->font_width*$i,$this->font_width*$i+10); $color = imagecolorallocate($img, rand(0,255), rand(0,255), rand(0,255)); imagettftext($img,$fontsize,$angle,$x,20,$color,$this->fontpath.’/’.$this->font,substr($this->text,$i,1)); } imagepng($img); //释放资源 imagedestroy($img); imagedestroy($bghanddle); } } new validimg($_SESSION['valid']); ?>

测试文件validtest.php

代码如下

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/** * 验证码测试 * @author  zcs */ session_start(); $_SESSION['valid']= randstr(); echo $_SESSION['valid']; //随机生成字符串 function randstr($num=4) { $chars = ‘ABDEFGHJKLMNPQRSTVWXYabdefghijkmnpqrstvwxy23456789′; $randstr=”; for($i=0;$i { $randstr.=substr($chars,rand(0,strlen($chars)),1); } return $randstr; } ?> 生成gif动态验证码 PHP生成GIF动画来实现动态图片验证码，以下是实现过程。 ImageCode函数通过GIFEncoder类实现的GIF动画 /**    * ImageCode 生成GIF图片验证    * @param $string 字符串    * @param $width 宽度    * @param $height 高度    * */  function ImageCode($string = '', $width = 75, $height = 25)   {       $authstr = $string ? $string : ((time() % 2 == 0) ? mt_rand(1000, 9999) : mt_rand(10000, 99999));               $board_width = $width;       $board_height = $height;       // 生成一个32帧的GIF动画       for($i = 0; $i     {           ob_start();           $image = imagecreate($board_width, $board_height);           imagecolorallocate($image, 0,0,0);           // 设定文字颜色数组            $colorList[] = ImageColorAllocate($image, 15,73,210);           $colorList[] = ImageColorAllocate($image, 0,64,0);           $colorList[] = ImageColorAllocate($image, 0,0,64);           $colorList[] = ImageColorAllocate($image, 0,128,128);           $colorList[] = ImageColorAllocate($image, 27,52,47);           $colorList[] = ImageColorAllocate($image, 51,0,102);           $colorList[] = ImageColorAllocate($image, 0,0,145);           $colorList[] = ImageColorAllocate($image, 0,0,113);           $colorList[] = ImageColorAllocate($image, 0,51,51);           $colorList[] = ImageColorAllocate($image, 158,180,35);           $colorList[] = ImageColorAllocate($image, 59,59,59);           $colorList[] = ImageColorAllocate($image, 0,0,0);           $colorList[] = ImageColorAllocate($image, 1,128,180);           $colorList[] = ImageColorAllocate($image, 0,153,51);           $colorList[] = ImageColorAllocate($image, 60,131,1);           $colorList[] = ImageColorAllocate($image, 0,0,0);           $fontcolor = ImageColorAllocate($image, 0,0,0);           $gray = ImageColorAllocate($image, 245,245,245);                       $color = imagecolorallocate($image, 255,255,255);           $color2 = imagecolorallocate($image, 255,0,0);                      imagefill($image, 0, 0, $gray);                      $space = 15;        // 字符间距           if($i > 0)          // 屏蔽第一帧           {               for ($k = 0; $k             {                    $colorRandom = mt_rand(0,sizeof($colorList)-1);                    $float_top = rand(0,4);                   $float_left = rand(0,3);                   imagestring($image, 6, $space * $k, $top + $float_top, substr($authstr, $k, 1), $colorList[$colorRandom]);               }           }                      for ($k = 0; $k         {                $colorRandom = mt_rand(0,sizeof($colorList)-1);                imagesetpixel($image, rand()%70 , rand()%15 , $colorList[$colorRandom]);                   }           // 添加干扰线           for($k = 0; $k         {               $colorRandom = mt_rand(0, sizeof($colorList)-1);                // $todrawline = rand(0,1);               $todrawline = 1;               if($todrawline)               {                   imageline($image, mt_rand(0, $board_width), mt_rand(0,$board_height), mt_rand(0,$board_width), mt_rand(0,$board_height), $colorList[$colorRandom]);               }               else                {                   $w = mt_rand(0,$board_width);                   $h = mt_rand(0,$board_width);                   imagearc($image, $board_width - floor($w / 2) , floor($h / 2), $w, $h,  rand(90,180), rand(180,270), $colorList[$colorRandom]);               }           }           imagegif($image);           imagedestroy($image);           $imagedata[] = ob_get_contents();           ob_clean();             ++$i;         }              $gif = new GIFEncoder($imagedata);         Header ('Content-type:image/gif');         echo $gif->GetAnimation();     }    验证码：       看不清？换一个

checkcode.php文件如下

代码如下	复制代码
? ini_set('display_errors', 'Off'); session_start();   if((strtoupper($_POST["code"])) == strtoupper(($_SESSION["VerifyCode"]))){  print("验证码正确,");   }else{     print("验证码错误,");   }   echo "提交的验证码:".strtoupper($_POST["code"]).",正确的验证码：".strtoupper($_SESSION["VerifyCode"]); ?>