Where can I find supported options for pcltoraster/rastertopcl?

[anonymous]

Which filter will insert user options to the print file pstoraster / 
rastertopcl ? Does those two filters support all user options listed in cups 
book? (e.g. brightness, gamma, sides, page-set, cpi, page-bottom, hue, 
scaling, position etc. )?

I want to apply my own pcl2pcl filter after cups rastertopcl filter, where 
could I tell CUPS? (change mime.convs / *cupsFilter in ppd file)

How could I tell whether a file is a PCL file. When I do "file test.pcl", it 
tells me PJL. (because there's a PJL wrap around for the PCL file)

Any help would be appreciated.