PHP使用GIFEncoder类处理gif图片实例

下面贴处理的源代码：

<?php

require_once("gifencoder.php");   //载入编码 文件

$gif = new GIFEncoder();              //实例化gif解码对象

$gif->load("test.gif");                    //载入要解码的gif图像

for($i=0;$i<sizeof($gif->IMGS["frames"]);$i++){       //根据 gif图像的帧数获取每帧的图像数据

$im = imagecreatefromstring($gif->getgif($i));        //利用GD库函数将GIF转得标准些

imagegif($im, $i.".gif");                                 //用文件形式保存生成的每帧图像数据，当然也可以用变量

}

imagedestroy($im);

ob_start();

for($i=0;sizeof($gif->IMGS["frames"]);$i++){

$im=imagecreatefromgif("0.gif");     //根据每帧的图片创建图像 

if($i>0){                                           //不是第一帧 复制图片和第一帧合并 

       $frame=imagecreatefromgif("$i.gif");        //读取当前帧的图像

        $w = imagesx($frame);                            //获取图像宽度

       $y= imagesy($frame);                           //获取图像高度

        imagecopy($im,$frame,0,0,0,0,$w,$y);    //把当前帧图像和第一帧图像复制合并

        imagedestroy($frame);                              //销毁当前图像

}

imagejpeg($im,$i."frame.jpg");       //合并后保存为jpg格式

$im=imagecreatefromjpeg($i."frame.jpg");    //从jpg格式重新创建图像

imagegif($im);                                                 //转为gif格式

imagedestroy($im);                                       //销毁图像

    $imagedata[] = ob_get_contents();       //创建这一帧的图像数据 

    ob_clean(); 

}

$diy[]=0;//开始延迟时间 

$gif = new GIFEncoder($imagedata,$diy,0,2,0,0,0,"bin");    //实例化gif编码对象

ob_start(); 

Header ('Content-type:image/gif'); 

echo $gif->GetAnimation(); 

?>

以上代码 基本就是一个完整的 读取一个gif图片，对其进行解码，然后再编码成gif图片的完整过程了..
有了这个就可以在网上随意抓取gif图片然后进行修改。甚至直接用php就可以自己制作一些gif图片.

GIFEncoder类源码：

 <?php

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 ) ? $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; $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 );

    }

}

?>