[comp.lang.postscript] setgray strangeness..

dberry@ (Daniel M. Berry) (06/20/91)

A student of mine developed a font with FontMatrix [.1 0 0 .1 ... ]
The characters of the font consist of pictures that require regions of
different shades of gray. Thus the routine for each character consists
of setgray's, closepath's, and fill's. We noticed that the font does not
work when the point size is set to less than 10. That is, the font works
fine at point size 10 or more, and at point size 9 or less, we get nothing.
Moreover, if you remove the setgray's, then they work at point size 9
(albeit the glyph does not look right!). Does anyone have an explanation?

One clue.. I noticed that at point size 10, some of the regions in some
of the characters are only one or two dots wide.

Thanks for your ideas

Dan

bytebug@dhw68k.cts.com (Roger L. Long) (06/23/91)

In article <10004@discus.technion.ac.il> Daniel M. Berry writes:
>A student of mine developed a font with FontMatrix [.1 0 0 .1 ... ]
>The characters of the font consist of pictures that require regions of
>different shades of gray. Thus the routine for each character consists
>of setgray's, closepath's, and fill's. We noticed that the font does not
>work when the point size is set to less than 10. That is, the font works
>fine at point size 10 or more, and at point size 9 or less, we get nothing.
>Moreover, if you remove the setgray's, then they work at point size 9
>(albeit the glyph does not look right!). Does anyone have an explanation?

You might notice that the Red book warns that "the use of setgray after a
setcachedevice operation within the scope of a BuildChar procedure is not
permitted (an undefined error results)."
-- 
	Roger L. Long
	bytebug@dhw68k.cts.com