[PD] pdp color seperation

[metafor]

hi list

i am wondering if someone already did a patch to separate color channels
in order to track some specific objects more easily. for example only
display objects with have a certain red value (bigger 200 in RGB) and
so on. 

i did some patches on my own, but i am not really satisfied and would
like to have a look on how other people achieved this goal. 

well just in case. otherwise good night or good morning wherever you
might be...

cheers
marc