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- Path: sparky!uunet!mcsun!Germany.EU.net!rrz.uni-koeln.de!not-for-mail
- From: aeg03@rrz.uni-koeln.de (Jan T. Kim)
- Newsgroups: comp.sys.atari.st.tech
- Subject: VDI suggestions (was: Sending objc_draw to a mem)
- Date: 16 Dec 1992 03:13:51 +0100
- Organization: Regional Computing Center, University of Cologne
- Lines: 43
- Message-ID: <1gm3cvINN18r8@rs1.rrz.Uni-Koeln.DE>
- References: <A55994@HB.maus.de> <A53826@MS.maus.de>
- Reply-To: kim@vax.mpiz-koeln.mpg.dbp.de
- NNTP-Posting-Host: rs1.rrz.uni-koeln.de
-
- In <A53826@MS.maus.de> Julian_Reschke@ms.maus.de (Julian Reschke) writes:
-
- >Patrick BETREMIEUX (bpat@cs.mcgill.ca) wrote:
- >[...]
- >>There is a way to set the width and height of the logical screen, so you
- >>may draw the whole list and then blit the part you want, but I don't have
- >>the books with me right now. Also, could someone tell me if it's a perfectly
- >>legal thing to do. It will work on any ST, and most probably on the STe, and
- >>MEGASTe. But does the TT still have this screen-switching stuff available ?
- >>Will the Falcon have it?
-
- >I guess so. However, it *is* bad programming practice, because you are
- >mixing different layers of the operating system (XBIOS and VDI), and
- >no one guarantees that this will have the side effects that you expect.
- >In fact, it won't work with some graphics cards.
-
- While this point is completely valid as such, I don't see any
- reason why the VDI should not support redirection of its output
- to virtual screens of arbitrary resolutions in x, y and color. In
- fact, I strongly suggest that next time the VDI is revised, VDI
- calls for this purpose should be introduced. Of course, that
- would increase incompatibility with PC-GEM, but that seems to be
- inevitable anyway. Besides, I don't care about that :-).
- Related to this, I found the MEMORY.SYS driver in the fontgdos
- package. However, there's no documentation on it, excepting a
- statement like "it prints to memory, of doubtful use at the end
- user level". Could anyone direct me to a source of more
- exhaustive information?
- Finally, I have recently posted the question whether it is
- possible to determine which drivers are installed with GDOS and
- available to a program. The answer seems to be that there is no
- VDI function to do this, the best thing to do is just opening a
- workstation on the desired device and to analyze the outcome of
- the v_opnwk() call. My second suggestion for a future VDI is
- therefore that a function for inquiring the available devices is
- provided.
-
- Greetinx, Jan
-
- +- Jan Kim -- X.400: S=kim;OU=vax;O=mpiz-koeln;P=mpg;A=dbp;C=de -+
- | Internet: kim@vax.mpiz-koeln.mpg.dbp.de |
- | |
- *----=< hierarchical systems are for files, not for humans >=-----*
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