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From: mckie@nas.nasa.gov (William McKie)
Newsgroups: alt.sys.sun,comp.graphics
Subject: SunPHIGS rubberband-like polyline
Message-ID: <1990Nov18.003415.27148@nas.nasa.gov>
Date: 18 Nov 90 00:34:15 GMT
Sender: news@nas.nasa.gov
Reply-To: mckie@amelia.nas.nasa.gov (William McKie)
Distribution: usa
Organization: NAS Program, NASA Ames Research Center, Moffett Field, CA
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We're currently using the SunPHIGS locator logical input device to
select 2 points with a rubber band line connecting them (device=1,
pet=-4), and we get a nice rubberband line which changes colour to
contrast with whatever pixel colour it crosses.  When we are done
selecting points with request locator, the rubberband line disappears
and the original pixels which it crossed are restored.  This all works
great.

What we're looking for now is a SunPHIGS mechanism which will allow us
to draw a polyline-like curve on top of an existing frame, which
behaves similarly to the rubberband locator input line described above.
I.e. we have a set of 2-D world coordinates which we would like the
curve to pass through (typically 2 pts), and we would like to make this
curve visible "on top" of the existing frame, and after an arbitrary
time for viewing, then turn the curve off and recover the pixels which
were originally "under it".  As in the locator rubberband line, we'd
like the colour of the curve to contrast with the original pixels (most
of our frames are completely area-shaded with a variety of colours).
Can someone suggest how this might be done?

Thanks,
-Bill McKie
NASA Ames Research Center
mckie@sky.arc.nasa.gov