php生成gif动画的方法，

<&#63;  
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", 
    ); 
 
    /* 
    ::::::::::::::::::::::::::::::::::::::::::::::::::: 
    :: 
    ::    GIFEncoder... 
    :: 
    */ 
    function GIFEncoder    ( 
                            $GIF_src, $GIF_dly, $GIF_lop, $GIF_dis, 
                            $GIF_red, $GIF_grn, $GIF_blu, $GIF_mod 
                        ) { 
        if ( ! is_array ( $GIF_src ) && ! is_array ( $GIF_tim ) ) { 
            printf    ( "%s: %s", $this->VER, $this->ERR [ 'ERR00' ] ); 
            exit    ( 0 ); 
        } 
        $this->LOP = ( $GIF_lop > -1 ) &#63; $GIF_lop : 0; 
        $this->DIS = ( $GIF_dis > -1 ) &#63; ( ( $GIF_dis < 3 ) &#63; $GIF_dis : 3 ) : 2; 
        $this->COL = ( $GIF_red > -1 && $GIF_grn > -1 && $GIF_blu > -1 ) &#63; 
                        ( $GIF_red | ( $GIF_grn << 8 ) | ( $GIF_blu << 16 ) ) : -1; 
 
        for ( $i = 0; $i < count ( $GIF_src ); $i++ ) { 
            if ( strToLower ( $GIF_mod ) == "url" ) { 
                $this->BUF [ ] = fread ( fopen ( $GIF_src [ $i ], "rb" ), filesize ( $GIF_src [ $i ] ) ); 
            } 
            else if ( 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; $i < count ( $this->BUF ); $i++ ) { 
            GIFEncoder::GIFAddFrames ( $i, $GIF_dly [ $i ] ); 
        } 
        GIFEncoder::GIFAddFooter ( ); 
    } 
    /* 
    ::::::::::::::::::::::::::::::::::::::::::::::::::: 
    :: 
    ::    GIFAddHeader... 
    :: 
    */ 
    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"; 
        } 
    } 
    /* 
    ::::::::::::::::::::::::::::::::::::::::::::::::::: 
    :: 
    ::    GIFAddFrames... 
    :: 
    */ 
    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; 
    } 
    /* 
    ::::::::::::::::::::::::::::::::::::::::::::::::::: 
    :: 
    ::    GIFAddFooter... 
    :: 
    */ 
    function GIFAddFooter ( ) { 
        $this->GIF .= ";"; 
    } 
    /* 
    ::::::::::::::::::::::::::::::::::::::::::::::::::: 
    :: 
    ::    GIFBlockCompare... 
    :: 
    */ 
    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 ); 
    } 
    /* 
    ::::::::::::::::::::::::::::::::::::::::::::::::::: 
    :: 
    ::    GIFWord... 
    :: 
    */ 
    function GIFWord ( $int ) { 
 
        return ( chr ( $int & 0xFF ) . chr ( ( $int >> 8 ) & 0xFF ) ); 
    } 
    /* 
    ::::::::::::::::::::::::::::::::::::::::::::::::::: 
    :: 
    ::    GetAnimation... 
    :: 
    */ 
    function GetAnimation ( ) { 
        return ( $this->GIF ); 
    } 
} 
 
&#63;> 

<&#63;php 
include "GIFEncoder.class.php"; 
/* 
  Build a frames array from sources... 
*/ 
if ( $dh = opendir ( "frames/" ) ) { 
  while ( false !== ( $dat = readdir ( $dh ) ) ) { 
    if ( $dat != "." && $dat != ".." ) { 
      $frames [ ] = "frames/$dat"; 
      $framed [ ] = 5; 
    } 
  } 
  closedir ( $dh ); 
} 
/* 
    GIFEncoder constructor: 
    ======================= 
 
    image_stream = new GIFEncoder  ( 
              URL or Binary data 'Sources' 
              int         'Delay times' 
              int         'Animation loops' 
              int         'Disposal' 
              int         'Transparent red, green, blue colors' 
              int         'Source type' 
            ); 
*/ 
$gif = new GIFEncoder  ( 
      $frames, 
      $framed, 
      0, 
      2, 
      0, 0, 0, 
      "url" 
    ); 
/* 
    Possibles outputs: 
    ================== 
 
    Output as GIF for browsers : 
      - Header ( 'Content-type:image/gif' ); 
    Output as GIF for browsers with filename: 
      - Header ( 'Content-disposition:Attachment;filename=myanimation.gif'); 
    Output as file to store into a specified file: 
      - FWrite ( FOpen ( "myanimation.gif", "wb" ), $gif->GetAnimation ( ) ); 
*/ 
Header ( 'Content-type:image/gif' ); 
echo  $gif->GetAnimation ( ); 
&#63;> 

<&#63;php 
include "GIFEncoder.class.php"; 
 
ob_start(); 
$board_width = 60; 
$board_height = 60; 
$pad_width = 5; 
$pad_height = 15; 
$ball_size = 5; 
$game_width = $board_width - $pad_width*2 - $ball_size; 
$game_height = $board_height-$ball_size; 
 
$x = 0; 
$y = rand(0,$game_height); 
$xv = rand(1,10); 
$yv = rand(1,10); 
$pt[] = array($x,$y); 
do{ 
    $x += $xv; 
    $y += $yv; 
    if($x > $game_width){ 
        $xv = -1*$xv; 
        $x = $game_width - ($x-$game_width); 
    }elseif($x < 0){ 
        $xv = -1*$xv; 
        $x = abs($x); 
    } 
    if($y>$game_height){ 
        $yv = -1*$yv; 
        $y = $game_height - ($y - $game_height); 
    }elseif($y<0){ 
        $yv = -1*$yv; 
        $y = abs($y); 
    } 
    $pt[] = array($x,$y); 
}while($x!=$pt[0][0]||$y!=$pt[0][1]); 
 
$i = 0; 
while(isset($pt[$i])){ 
    $image = imagecreate($board_width,$board_height); 
    imagecolorallocate($image, 0,0,0); 
    $color = imagecolorallocate($image, 255,255,255); 
    $color2 = imagecolorallocate($image, 255,0,0); 
     
    if($pt[$i][1] + $pad_height < $board_width){ 
        imagefilledrectangle($image,0,$pt[$i][1],$pad_width, $pt[$i][1]+$pad_height,$color); 
    }else{ 
        imagefilledrectangle($image,0,$board_width-$pad_height,$pad_width, $board_width,$color); 
    } 
    imagefilledrectangle($image,$board_width-$pad_width,0,$board_width, $board_height,$color2); 
    imagefilledrectangle($image,$pad_width+$pt[$i][0], $ball_size+$pt[$i][1]-$ball_size, $pad_width+$pt[$i][0]+$ball_size, $ball_size+$pt[$i][1],$color); 
    //imagesetpixel($image,$pt[$i][0],$pt[$i][1],$color); 
    imagegif($image); 
    imagedestroy($image); 
    $imagedata[] = ob_get_contents(); 
    ob_clean(); 
    ++$i; 
} 
 
$gif = new GIFEncoder( 
              $imagedata, 
              100, 
              0, 
              2, 
              0, 0, 1, 
              "bin" 
    ); 
     
Header ('Content-type:image/gif'); 
echo $gif->GetAnimation(); 
&#63;>