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<?php  /**  *ImageCode 生成包含验证码的GIF图片的函数  *@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<32;$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              $top=0;              for($k=0;$k<strlen($authstr);$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<20;$k++){               $colorRandom=mt_rand(0,sizeof($colorList)-1);              imagesetpixel($image,rand()%70,rand()%15,$colorList[$colorRandom]);                 }          // 添加干扰线          for($k=0;$k<3;$k++){              $colorRandom=mt_rand(0,sizeof($colorList)-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();  }        /**  *GIFEncoder类  **/  Class GIFEncoder{      var $GIF="GIF89a";              /* GIF header 6 bytes       */       var $VER="GIFEncoder V2.06";      /* Encoder version            */       var $BUF=Array();      var $LOP=0;      var $DIS=2;      var $COL=-1;      var $IMG=-1;      var $ERR=Array(          'ERR00'=>"Does not supported function for only one image!",           'ERR01'=>"Source is not a GIF image!",           'ERR02'=>"Unintelligible flag ",           'ERR03'=>"Could not make animation from animated GIF source",      );      function GIFEncoder($GIF_src,$GIF_dly=100,$GIF_lop=0,$GIF_dis=0, $GIF_red=0,$GIF_grn=0,$GIF_blu=0,$GIF_mod='bin'){          if(!is_array($GIF_src)&&!is_array($GIF_tim)){              printf("%s: %s",$this->VER,$this->ERR['ERR00']);              exit(0);          }            $this->LOP=($GIF_lop>-1)?$GIF_lop:0;          $this->DIS=($GIF_dis>-1)?(($GIF_dis<3)?$GIF_dis:3):2;          $this->COL=($GIF_red>-1&&$GIF_grn>-1&&$GIF_blu>-1)?($GIF_red |($GIF_grn<<8)|($GIF_blu<<16)):-1;             for($i=0,$src_count=count($GIF_src);$i<$src_count;$i++){              if(strToLower($GIF_mod)=="url"){                  $this->BUF[]=fread(fopen($GIF_src [$i],"rb"),filesize($GIF_src [$i]));             }elseif(strToLower($GIF_mod)=="bin"){                  $this->BUF [ ]=$GIF_src [ $i ];             }else{                  printf("%s: %s(%s)!",$this->VER,$this->ERR [ 'ERR02' ],$GIF_mod);                  exit(0);             }                if(substr($this->BUF[$i],0,6)!="GIF87a"&&substr($this->BUF [$i],0,6)!="GIF89a"){                  printf("%s: %d %s",$this->VER,$i,$this->ERR ['ERR01']);                  exit(0);             }                for($j=(13+3*(2<<(ord($this->BUF[$i]{10})&0x07))),$k=TRUE;$k;$j++){                  switch($this->BUF [$i]{$j}){                      case "!":                            if((substr($this->BUF[$i],($j+3),8))=="NETSCAPE"){                                  printf("%s: %s(%s source)!",$this->VER,$this->ERR ['ERR03'],($i+1));                                  exit(0);                         }                            break;                      case ";":                            $k=FALSE;                      break;                 }               }            }            GIFEncoder::GIFAddHeader();          for($i=0,$count_buf=count($this->BUF);$i<$count_buf;$i++){              GIFEncoder::GIFAddFrames($i,$GIF_dly[$i]);         }            GIFEncoder::GIFAddFooter();      }        function GIFAddHeader(){          $cmap=0;          if(ord($this->BUF[0]{10})&0x80){              $cmap=3*(2<<(ord($this->BUF [0]{10})&0x07));              $this->GIF.=substr($this->BUF [0],6,7);              $this->GIF.=substr($this->BUF [0],13,$cmap);              $this->GIF.="!\377\13NETSCAPE2.0\3\1".GIFEncoder::GIFWord($this->LOP)."\0";          }        }        function GIFAddFrames($i,$d){          $Locals_str=13+3*(2 <<(ord($this->BUF[$i]{10})&0x07));          $Locals_end=strlen($this->BUF[$i])-$Locals_str-1;          $Locals_tmp=substr($this->BUF[$i],$Locals_str,$Locals_end);          $Global_len=2<<(ord($this->BUF [0]{10})&0x07);          $Locals_len=2<<(ord($this->BUF[$i]{10})&0x07);          $Global_rgb=substr($this->BUF[0],13,3*(2<<(ord($this->BUF[0]{10})&0x07)));          $Locals_rgb=substr($this->BUF[$i],13,3*(2<<(ord($this->BUF[$i]{10})&0x07)));          $Locals_ext="!\xF9\x04".chr(($this->DIS<<2)+0).chr(($d>>0)&0xFF).chr(($d>>8)&0xFF)."\x0\x0";          if($this->COL>-1&&ord($this->BUF[$i]{10})&0x80){              for($j=0;$j<(2<<(ord($this->BUF[$i]{10})&0x07));$j++){                  if(ord($Locals_rgb{3*$j+0})==($this->COL>> 0)&0xFF&&ord($Locals_rgb{3*$j+1})==($this->COL>> 8)&0xFF&&ord($Locals_rgb{3*$j+2})==($this->COL>>16)&0xFF){                      $Locals_ext="!\xF9\x04".chr(($this->DIS<<2)+1).chr(($d>>0)&0xFF).chr(($d>>8)&0xFF).chr($j)."\x0";                      break;                 }               }            }            switch($Locals_tmp{0}){              case "!":                    $Locals_img=substr($Locals_tmp,8,10);                  $Locals_tmp=substr($Locals_tmp,18,strlen($Locals_tmp)-18);                  break;              case ",":                    $Locals_img=substr($Locals_tmp,0,10);                  $Locals_tmp=substr($Locals_tmp,10,strlen($Locals_tmp)-10);                  break;          }            if(ord($this->BUF[$i]{10})&0x80&&$this->IMG>-1){              if($Global_len==$Locals_len){                  if(GIFEncoder::GIFBlockCompare($Global_rgb,$Locals_rgb,$Global_len)){                      $this->GIF.=($Locals_ext.$Locals_img.$Locals_tmp);                  }else{                      $byte=ord($Locals_img{9});                      $byte|=0x80;                      $byte&=0xF8;                      $byte|=(ord($this->BUF [0]{10})&0x07);                      $Locals_img{9}=chr($byte);                      $this->GIF.=($Locals_ext.$Locals_img.$Locals_rgb.$Locals_tmp);                  }                }else{                  $byte=ord($Locals_img{9});                  $byte|=0x80;                  $byte&=0xF8;                  $byte|=(ord($this->BUF[$i]{10})&0x07);                  $Locals_img {9}=chr($byte);                  $this->GIF.=($Locals_ext.$Locals_img.$Locals_rgb.$Locals_tmp);              }            }else{              $this->GIF.=($Locals_ext.$Locals_img.$Locals_tmp);          }            $this->IMG=1;      }        function GIFAddFooter(){          $this->GIF.=";";      }        function GIFBlockCompare($GlobalBlock,$LocalBlock,$Len){          for($i=0;$i<$Len;$i++){              if($GlobalBlock{3*$i+0}!=$LocalBlock{3*$i+0}||$GlobalBlock{3*$i+1}!=$LocalBlock{3*$i+1}||$GlobalBlock{3*$i+2}!=$LocalBlock{3*$i+2}){                  return(0);             }           }            return(1);      }        function GIFWord($int){         return(chr($int&0xFF).chr(($int>>8)&0xFF));      }        function GetAnimation(){          return($this->GIF);      }    }

/*调用示例*/  session_start();  $checkCode='';  $chars='abcdefghjkmnpqrstuvwxyzABCDEFGHJKLMNPRSTUVWXYZ23456789';  for($i=0;$i<4;$i++){      $checkCode.=substr($chars,mt_rand(0,strlen($chars)-1),1);  }  $_SESSION['code']=strtoupper($checkCode);// 记录session  ImageCode($checkCode,60);// 显示GIF动画