PHP实现GIF图片验证码

这是一个用PHP生成GIF动画来实现动态图片验证码的程序，非常实用，是php用户注册登录界面经常需要用到的验证码程序，有需要GIF动态图片验证码功能的朋友可以收藏一下。

第一步：创建ImageCode.php文件，验证码生成函数代码如下：

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 = rand(0,1);
  $todrawline = 1;
  if($todrawline)
  {
    imageline($image,mt_rand(0,$board_width),$board_height),$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 )!",$this->ERR [ 'ERR02' ],$GIF_mod);

   exit(0); 

  }
  if (substr($this->BUF[$i],6) != "GIF87a" && substr($this->BUF [$i],6) != "GIF89a")

  {

   printf( "%s: %d %s",$i,$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->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 ],7);

  $this->GIF .= substr ( $this->BUF [ 0 ],13,$cmap);
  $this->GIF .= "!37713NETSCAPE2.031" . GIFEncoder::GIFWord ( $this->LOP ) . "";
  }
  }
  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],3 (2 << ( ord ( $this->BUF[0]{10} ) & 0x07)));
  $Locals_rgb = substr ( $this->BUF[$i],3 * (2 << ( ord ( $this->BUF[$i]{10} ) & 0x07)));
  $Locals_ext = "!xF9x04" . chr(($this->DIS << 2) + 0) . chr(($d >> 0) & 0xFF) . chr(($d >> 8) & 0xFF) . "x0x0";
  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 )

   { 
     $Locals_ext = "!xF9x04" . chr(($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,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);
}
}

第二步：验证码生成，创建yzimg.php，并引用入文件ImageCode.php。代码如下：