PHP生成GIF动态图片验证码

作者:袖梨 2022-06-24
 代码如下 复制代码

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


/**
 * 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 .= "!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], 13, 3 * (2 << ( ord ( $this->BUF[0]{10} ) & 0x07))); 
        $Locals_rgb = substr ( $this->BUF[$i], 13, 3 * (2 << ( ord ( $this->BUF[$i]{10} ) & 0x07))); 

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

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