Re: TO.Graph on a ROM 03 IIgs?

[dempson@swell.actrix.gen.nz (David Empson)]

In article <2j0e95INNsn@newsman.csu.murdoch.edu.au>
hinchlif@csuvax1.csu.murdoch.edu.au (Peter Hinchliffe) writes:
> I would like to hear from anyone who uses TimeOut Graph on a ROM 03 IIgs. A
> friend has such a beast, and although TO.Graph works OK (ie, it doesn't crash)
> it does not draw properly on the DHR screen. It's possible to make out the
> graph itself, but it is drawn against what can only be described as a "black
> and white mess".

I don't use Timeout Graph, but I'll see what I can do to help.

This is probably because the most recently used program left the
"NewVideo" register set up to use Super Hi-Res graphics mode (which it
shouldn't have done).  When bit 6 of this register is set, the memory
area from $01/$2000-$9FFF is rearranged to support Super Hi-Res
graphics.  This bit must be clear for Double Hi-Res to work properly.

Another possibility is that monochrome mode was enabled but Timeout
Graph is attempting to draw in colour.  In this case, you should see a
clear enough picture, but it is black and white, with bit patterns
representing different colours.  This doesn't seem likely from your
description.

> If we access TimeOut Paint first, however, the DHR screen seems to clear
> properly, and TO Graph then works as it should. It's as though the interleaving
> of the HiRes graphics pages is not being done properly on the ROM 03.

This probably means that Timeout Paint is setting the NewVideo
register correctly, but Timeout Graph relies on an earlier program
setting it.  (This register is specific to the IIgs, so it is not
unreasonable to ignore it in ProDOS-8 software.)

Is your friend booting directly into ProDOS-8 or via GS/OS?  Which
program launcher does he use to get into AppleWorks?  I'm pretty sure
that Finder/QuickDraw will set NewVideo properly, but I don't know
about non-desktop Super Hi-Res launchers like ProSel-16.

> I have used TO Graph for many years - first on a IIc, then on a 1 meg IIe, and
> now on a ROM 01 IIgs, and have never had a single problem with it. I am very
> interested to hear if this is a common problem with the program on the ROM 03
> IIgs, or if perhaps the problem lies deep in his software.

There is no difference in the hardware implementation of Super Hi-Res
and Double Hi-Res graphics modes between a ROM 01 and ROM 03.  There
may be differences in how the NewVideo register is initialized at
reset time, though.
-- 
David Empson                                                               
dempson@swell.actrix.gen.nz                                                
Snail mail: P.O. Box 27-103, Wellington, New Zealand