尝试多次直接用GD库给gif图片加水印均未达到理想效果后，决定用imagick扩展给gif图片加水印，虽然帧数太多的情况下速度不太给力外，效果蛮理想。

开启imagick扩展，可参考http://www.vpser.net/manage/lnmp-lnmpa-imagemagick-install-tutorial.html

果断先上图：

再上代码：

$image_name = '01351346.gif';
//$image_name = 'Left_spinning_dancer.gif';
//$image_name = 'gifmerge.gif';

function createTextImagickDraw($fontSize=12, $fillColor='', $underColor='', $font='msyh.ttf'){
	$draw = new ImagickDraw();
	$draw->setFont($font);
	$draw->setFontSize($fontSize);
	//$draw->setGravity(Imagick::GRAVITY_SOUTHEAST);//设置水印位置
	if(!empty($underColor)) $draw->setTextUnderColor(new ImagickPixel($underColor));
	if(!empty($fillColor)) $draw->setFillColor(new ImagickPixel($fillColor));
	return $draw;
}

function createWaterImagickDraw($waterImg='water.png',$x=10,$y=85,$width=16,$height=16){
	$water = new Imagick($waterImg);
	//$second->setImageOpacity (0.4);//设置透明度
	$draw = new ImagickDraw();
	//$draw->setGravity(Imagick::GRAVITY_CENTER);//设置位置
	$draw->composite($water->getImageCompose(), $x, $y, $width, $height,$water);

	return $draw;

}
$image = new Imagick($image_name);
$animation = new Imagick();
$animation->setFormat( "gif" );
$image = $image->coalesceImages();
$unitl = $image->getNumberImages();

for ($i=0; $i<$unitl; $i++) {
	$image->setImageIndex($i);
	$thisimage = new Imagick();
	$thisimage->readImageBlob($image);
	$delay = $thisimage->getImageDelay();
	$thisimage->annotateImage(createTextImagickDraw(12, 'red'), 30, 100, 0, '阿维卡');
	$thisimage->annotateImage(createTextImagickDraw(12, 'green'), 10, 120, 0, 'http://kller.cn');
	$thisimage->annotateImage(createTextImagickDraw(12, 'blue'), 10, 140, 0, 'http://www.aweika.com');
	$thisimage->drawImage(createWaterImagickDraw('f.jpg'));
	$animation->addImage($thisimage);
	$animation->setImageDelay( $delay );
}
$animation->writeImages('new/'.$image_name, true);
header( "Content-Type: image/gif" );
echo $animation->getImagesBlob();

附件：（你们懂的）

imagick.zip