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From: peter@citylink.dinoex.sub.org (Peter Much)
Subject: Re: Magic /etc/XF* numbers
Organization: Buero fuer Sektenforschung und Qualitaetspruefung in der Esoterik
Message-ID: <DA4GBB.6qq@citylink.dinoex.sub.org>
References: <3r4qqu$rc0@engnews2.Eng.Sun.COM>
Date: Tue, 13 Jun 1995 17:23:35 GMT
Lines: 62
In article <3r4qqu$rc0@engnews2.Eng.Sun.COM>,
Eric van Bezooijen <ericvb@Sun.COM> wrote:
>I have a ATI pro turbo 2 Mb VRAM (mach64 chip) card, I've been mucking
>around with the /etc/XF86Config file. I got 1024x768 working, but I
>know my card can do lots of different resolutions. The graphics card
>manual only goes so far, and there are 6 "magic numbers" that I cannot
>figure out (this is from memory):
>
>HResolution: 1024 <number> <number> <number>
>VResolution: 768 <number> <number> <number>
>
>I know that the first set of numbers is resolution, but what do they
>other 6 signify ? How do I generate them ? Is there any place where
>I can find these numbers ? The FAQ was not useful enough and a X server
>probe lists lots of numbers, but I don't which numbers to extract.
This is quite easy, when considering how a monitor does work.
The cathode ray beam walks "slowly" from left to right, while writing
one line of pixels on the screen.
Then the beam's intensity is swithed off, and the beam goes back to the
left border very fast - and there starts to write the next line of pixels.
This is the horizontal behaviour, the vertical is just similar: After
having written all lines of pixels, the beam goes back to the upper
screen-border and starts over again.
The walking back of the beam is called horizontal rsp. vertical retrace.
So we already need four numbers: The number of viewable pixels on the
screen, and the number of pixels that won't get displayed while the dar-
kened beam goes back to the left/upper side of the screen (monitor- and
card-dependant).
The next point is: The beam is not able to change it's direction in
zero-time. So we need additional numbers for the pixels not getting dis-
played while the beam changes direction (on both sides).
Considering this for horizontal and for vertical behaviour, shows that
we need 8 numbers.
The meaning of the columns is as follows:
1.: number of viewable pixels
2.: same as 1, plus number of non-viewable pixels while changing direction
on the right or bottom.
3.: same as 2, plus number of non-viewable pixels during retrace.
4.: same as 3, plus numbr of pixels during direction change on the left or
upper.
The advantage of this fine-tuning is that you can best operation from
nearly all types of monitors, You are not bound to the usual screen-sizes
(like 800x600, 1024x768 etc.) but can use any sceen-size your monitor is
able to display, You can adjust the screen-borders' width, etc. The dis-
advantage is that it is quite annoying to adjust these values.
Usually, You're better off -if You have a well-known graphics-card and
monitor- if you're using some values already tested for that hardware.
There should be some in the documentations.
Peter
--
Write to: Peter Much * Koelnische Str. 22 * D-34117 Kassel * +49-561-774961
peter@citylink.dinoex.sub.org much@hrz.uni-kassel.de p.much@asco.nev.sub.de