Watermark on animated gif with php - php

Question

I need a function that adds a watermark to an animated gif. How I can do that with PHP and ImageMagick?
This is my code, but it doesn't work.
function IMagickWatermark($sf, $sfDest, $sfLogo, $sGravity='southeast'){
//$sCmd = "composite -compose bumpmap -gravity $sGravity $sfLogo \"$sf\" $sfDest";
$sCmd = "convert \"$sf\" -coalesce -gravity south -draw 'image over 0,0 0,0 \"$sfLogo\"' \"$sfDest\"";
exec($sCmd);
return 1;
}
$sf = $_SERVER['DOCUMENT_ROOT']."/test/source.gif";
$sfDest = $_SERVER['DOCUMENT_ROOT']."/test/dest.gif";
$sfLogo = $_SERVER['DOCUMENT_ROOT']."/test/logowithtext.gif";
IMagickWatermark($sf, $sfDest, $sfLogo, $sGravity='SouthEast');

Answer 1

Try this:
$animation = ani.gif;
$watermark = logo.png;
$watermarked_animation = "morph.gif";
$cmd = " $animation -coalesce -gravity South ".
" -geometry +0+0 null: $watermark -layers composite -layers optimize ";
exec("convert $cmd $watermarked_animation ");

Answer 2

<?php
shell_exec('for i in sphere*.gif; do convert $i -font Arial -pointsize 20 \
-draw "gravity south \
fill black text 0,12 \'Copyright\' \
fill white text 1,11 \'Copyright\' " \
wmark_$i; done');
shell_exec("convert -delay 20 -loop 0 wmark_sphere*.gif animatespheres.gif");
$f = fopen("animatespheres.gif", 'rb');
fpassthru($f);
fclose($f);
?>
if you need to debug, remove the fopen,fpassthru,fclose lines and add echo's for the shell_execs.