Path: utzoo!attcan!uunet!husc6!mailrus!ames!pasteur!ucbvax!decwrl!hplabs!hpda!hp-sde!hpfcdc!hpldola!paul
From: paul@hpldola.HP.COM (Paul Bame)
Newsgroups: comp.graphics
Subject: Re: HP 9000 Screen Dump to HP Laser printer
Message-ID: <11390009@hpldola.HP.COM>
Date: 24 May 88 19:05:23 GMT
References: <286@gt-eedsp.UUCP>
Organization: HP Elec. Design Div. -ColoSpgs
Lines: 31

> / hpldola:comp.graphics / jensen@gt-eedsp.UUCP (P. Allen Jensen) /  9:36 am  May 18, 1988 /
> I need a program to do a screen-dump from an HP9000c320.  The images are
> being done in gray-scale.

graphics(7) in the HP-UX manuals details how to talk directly to the
frame buffer - it's just a big array - and it's easy to do:

	fd = open(/dev/crt)
	ioctl(fd, GCMAP?, &ptr)

This takes from 2 to 10 lines depending on how neat you are and how much
error checking you do.  Newer versions of Starbase also do such things
as screen dumps but I don't have a reference, look up the 'pcltrans' program.

>                            The hard-copy devices I have to choose from
> are an Apple Laserwriter Plus, an HP Laserjet, and a QMS Laserprinter.

The other half of your problem is how to represent the gray-scale image
on a non-gray-scale printer.  I believe Postscript allows you to push
a gray-scale image at the printer without worrying about this problem -
otherwise you'll have to dither or threshold your image before printing.

> The software should be free and I need source.

The pseudo-code and the graphics(7) reference should be enough to solve
your first problem quickly.  The second part isn't specified well enough
to know what to say about it.


	--Paul Bame
	hplabs!hpldola!paul