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From: mckie@amelia.nas.nasa.gov (William McKie)
Newsgroups: comp.graphics
Subject: (Sun)PHIGS questions
Message-ID: <5276@amelia.nas.nasa.gov>
Date: 21 Mar 90 20:47:53 GMT
Reply-To: mckie@amelia.nas.nasa.gov (William McKie)
Distribution: usa
Organization: NASA Ames Research Center, Moffett Field, CA
Lines: 41

We're running SunPHIGS 1.1 on our Sun-4/370-GX under 4.0.3 and SunView.
We've written several applications using SunPHIGS, and they are mostly
working, but the following questions have come up.

The colour at any pixel appears as the logical OR of the background
colour and the colour of any foreground structure items.  E.g. if
we select a red background colour, and draw a green line, the colour
of the line on the display is yellow.  This is useful in many
situations, but we are wondering if there is a way to specify that
the colour of the latest drawn item is to be the actual colour of
that item, i.e. no mixing of foreground and background colours?

We are creating graphics output on both the Sun console screen
(as a command tool workstation), and on binary and clear cgm
files.  We are wondering if there is a way to input the contents of
a cgm file into a SunPHIGS program, e.g. with each cgm frame
becoming a 2-D PHIGS structure which could then be displayed on the
console in rapid succession.  The goal would be to to animate
sequences of images in a post-process when the time to generate
the original images is too long for direct animation.

By examining clear cgm output files from SunPHIGS programs, it
appears that when the program selects black as the background
colour (cgm workstation colour index 0), the cgm output file
contains no explicit declaration of background colour.  Other
background colour selections within SunPHIGS result in an
explicit "BACKCOLR r g b" statement in the cgm file.  Is this
correct behavior?  I.e. is the default background colour in
cgm black?  Our cgm translators and displayers appear to
interpret the default cgm background colour as white, which is
usually not what we intended when we selected black.

The SunPHIGS reference manual is comprehensive and great for
reference purposes, and the Sun Getting Started with SunPHIGS
monograph is in many ways helpful, but we would like to find a
good text on PHIGS.  Can anyone recommend a popular one?

Thanks for any ideas on any of the above,
-Bill McKie
NASA Ames Research Center
mckie@sky.arc.nasa.gov