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From: dwatola@NEXTASY2.EECS.WSU.EDU (David Watola)
Newsgroups: comp.sys.next
Subject: graphics portability between ns and ns-color
Message-ID: <9106050533.AA20158@nextasy2.eecs.wsu.edu>
Date: 5 Jun 91 05:31:32 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
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X-Unparsable-Date: Tue, 4 Jun 91 22:33:29 GMT-5632:48

theoretically, the same grayscale dps code should produce the same result
on a color nextstation as a monochrome nextstation, right?  i don't typically
get to use a color station, but i just ran across a little problem that
prevented me from giving a demo on a color machine.

i have a custom view class that draws one of a set of NXImages cached as
NXEPSImageReps.  The drawing routine for this custom view only does one thing--
it does a

  [theNXImage drawRepresentation:theNXEPSImageRep inRect:&theBounds]

which draws a properly scaled version of that image in the view.  TFM
says that drawRepresentation:inRect: fills in the view with the background
color, then draws the image.

the problem is that this background color is white on a monochrome system,
and black (same as the pen color, unfortunately) on a color system.  why?
i never explictly set any background colors, and the default color is
NX_COLORCLEAR (i.e. transparent).  so why does transparent mean white on one
system and black on the other?

just wondering...  doesn't matter too much.

dave watola
dwatola@yoda.eecs.wsu.edu