🚀 go-pugleaf

Hi,

I'm trying to convert a colour (AutoCAD "slide" format) file into
a *monochrome* sun rasterfile.  I can use PBMplus to do the job thus:

	bash$ sldtoppm -adjust file.sld |
	      ppmtopgm |
	      pgmtopbm |
	      pbmtorast > file.ras

The above works, but it appears that the process involves *dithering*
the colour image (I suppose "pgmtopbm" does this).  I really don't want
dithering, since the final image comes out looking too grainy.  My
original colour images contain only *six* colours (they are simple plan
diagrams of buildings and campuses).  What I would like to do is
translate anything that is not black from the original into white.
Something like:

	INPUT		   OUTPUT
	black (0)	-> black (0)
	non-black (1-?)	-> white (1)

This way, the output should sharper.  All I want is for the walls
of buildings and roads to show up clearly.  Is there some alternative way of
performing the conversion, so that no dithering is involved?


Thanks


Rob Sturrock
<rns@deakin.EDU.AU>
Computing Services, Deakin University