PHP使用GIFEncoder类处理gif图片实例
这篇文章主要介绍了PHP使用GIFEncoder类处理gif图片实例,包含解码GIF图片、处理后再次生成GIF图片例子,需要的朋友可以参考下
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 ); } } ?>