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  From: Ketil Froyn <ketilf@ifi.uio.no>
  To  : ggi-develop@eskimo.com
  Date: Tue, 25 May 1999 11:36:00 +0200 (MET DST)

Re: Strange fb-stuff?

On Mon, 24 May 1999, Andreas Beck wrote:

> Hmm in Theory you should be able to go as far as
> 1176*882 = 1037232 < 1048576 = 1024*1024
> (I compare 16 bit word here, you need 1037232, you have 2MB/2 = 1M 16-bit
> words)

I guess, I'm just too lazy to do math myself :) And I don't know what is
limited by the screen or gfx-card.

> > But, on the console, when I change
> > to 1168x876, I first realised I only had 51 lines, as opposed to 54 lines
> ? How do you find that value ? Count some cleverly drawn lines ?

No. I write 'resize', and that tells me how many lines. Also, I made a
small app in perl that counts down from 100 to 2, and writes each number
on a line. Then, after this is run, the top number on the screen is the
number of lines you have.

> I suppose you have tunes the picture size to have a pretty loose fit WRT to
> the monitor edges, so you would see extra chars appearing - right ?

There is nothing outside the screen, if that's what you meant :)

> > when I'm running 1154x864. So I looked at what fbset gave me, and that
> > was:
> > mode "1168x876x16"
> >     # D: 142.857 MHz, H: 89.509 kHz, V: 102.297 Hz
> >     geometry 1168 819 1280 819 16
> >     timings 7000 236 80 48 6 112 2
> > endmode
> > Why only 819?
> Look at the virtual resolution. The card does not seem to allow anything
> between 1152 (btw - you talk about 1154, which is very strange, as few cards
> can do resolutions with x not being a multiple of 8 pixels) and 1280 for
> virtual resolution. That leaves you with:
(I meant 1152x864)
> 1024*1024/1280=819.20000

Aha! So I'm using up the memory for virtual resolution...? That does
explain this.

> > Another thing I was wondering about, was how to choose a dotclock. Do I
> > use the highest one possible that works with the resolution, or...?
> You choose it due to maximum monitor ratings. A few rule-of-thumb formulas:
[snip]
Thanks!

> > Another thing is that, on the console, when I use fbset to resize, the
> > pointer (gpm) cannot move outside the space the screen took before I
> > resized. Is there something I can do about that?
> Kill and restart it.

OK. I don't know how this will work if I have different sized consoles,
but I don't really need that. I only end up with it sometimes while I'm
testing.

Ketil Froyn
--
He who Laughs, Lasts.

http://www.ifi.uio.no/~ketilf/       
mailto:ketilf@ifi.uio.no

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