🚀 go-pugleaf

> In article <1992Oct2.163303.15592@ringer.cs.utsa.edu>,  
gonzo@lonestar.utsa.edu (Jerry . Gonzalez) writes...
> > 
> >I was wondering if there is a way to do transparent 
> >halftoning?  Well, let me explain what I'm doing.
> >By using PostScript I've already got an image of a
> >brain displayed.  Now, what I need to do is overlay
> >a grid of boxes (filled with different gray tones) 
> >over the brain.  Is there a way to make this boxes 
> >somewhat transparent so the brain image can still
> >be seen under the boxes?  Hope thus made sense.
> >

Another way would be to create your transparent overlay  
before you turn the bit map into a PS file.  This wouldn't  
be too hard using the pbmplus series of utilities.

Create your image of the brain > transform to a pgm file.
Create your boxes with grey values > transform to a pgmfile
Now use pnmarith to add the two values together.  
And then convert that to a postscript file.