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From: rrd@hpfcso.FC.HP.COM (Ray Depew)
Newsgroups: comp.sys.handhelds
Subject: Re: HP48: Displaying PICT; is there another way?
Message-ID: <7360106@hpfcso.FC.HP.COM>
Date: 30 Apr 91 21:52:26 GMT
References: <1991Apr23.175400.8672@nntp-server.caltech.edu>
Organization: Hewlett-Packard, Fort Collins, CO, USA
Lines: 30

To tim@nijinsky.ipac.caltech.edu (Tim Conrow)

> I was working on my own home grown calender program (as though there
> weren't enough out there already) ...

:-)

> So what am I missing? How does one update a displayed GROB as fast as
> possible in response to a key press, preferably "in place", i.e. w/o
> having to go through an \->LCD phase? (How is it done, for example, in
> the periodic table display on the EQ LIB card?)

The trick is to use { # 0 # 0 } PVIEW near the start of your program, and
then use REPL, GOR, GXOR and GAND (if you can write it) to update only
certain parts of your grob.  If you do have to update huge sections of
your grob, then it's best to do it offline and use REPL to import the entire
new grob to PICT.  There are just too many problems associated with 
operations that affect PICT directly, like PICT STO.  That's where a lot of
the flicker comes from.

You might consider buying the book "HP48 Graphics", written by a good friend
of mine.  It contains a lot of work on graphics fundamentals on the 48, and
a pretty decent calendar routine :-) , written by Ron Johnson et al and used
by permission.


Regards
Ray Depew
HP ICBD -- IC's By Dictatorship
rrd@hpfitst1.hp.com