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=newGIFEncoder(); //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
$gif=newGIFEncoder($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 ClassGIFEncoder{ var$GIF="GIF89a"; /*GIFheader6bytes */ var$VER="GIFEncoderV2.06"; /*Encoderversion */ var$BUF=Array(); var$LOP= 0; var$DIS= 2; var$COL=-1; var$IMG=-1; var$ERR=Array( 'ERR00'=>"Doesnotsupportedfunctionforonlyoneimage!", 'ERR01'=>"SourceisnotaGIFimage!", 'ERR02'=>"Unintelligibleflag", 'ERR03'=>"CouldnotmakeanimationfromanimatedGIFsource", ); /* ::::::::::::::::::::::::::::::::::::::::::::::::::: :: :: GIFEncoder... :: */ functionGIFEncoder ( $GIF_src,$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[$i])); } elseif(strToLower($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],($j+3),8))=="NETSCAPE"){ printf ("%s:%s(%ssource)!",$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... :: */ functionGIFAddHeader(){ $cmap=0; if(ord($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... :: */ functionGIFAddFrames($i,$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... :: */ functionGIFAddFooter(){ $this->GIF.=";"; } /* ::::::::::::::::::::::::::::::::::::::::::::::::::: :: :: GIFBlockCompare... :: */ functionGIFBlockCompare($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... :: */ functionGIFWord($int){ return(chr($int&0xFF).chr(($int>>8)&0xFF)); } /* ::::::::::::::::::::::::::::::::::::::::::::::::::: :: :: GetAnimation... :: */ functionGetAnimation(){ return($this->GIF); } } ?>