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From: dempson@atlantis.actrix.gen.nz (David Empson)
Subject: Re: Double-High Res Page 2?
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Date: Thu, 16 Feb 1995 21:57:29 GMT
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In article <3hvutp$bkj@fishlab3.fsh.mtu.edu>,
Joshua P. Onge <jponge@mtu.edu> wrote:
> David Empson (dempson@atlantis.actrix.gen.nz) wrote:
> 
> : double lo-res graphics (page 1)  $0400-$07FF     $0400-$07FF
> 
> Did you say "double lo-res graphics"?  I've never heard of this.

Not surprising - Apple have never officially documented it.  It is not
mentioned in any of the technical/hardware reference manuals.

Even more surprising: the IIc and IIgs have firmware and Applesoft
support for it!

On the IIc and IIgs, you can access double lo-res mode from Applesoft
as follows:

10 D$=CHR$(4)
20 PRINT D$;"PR#3": REM 80-column mode
30 POKE 49246,0: REM $C05E - enable double resolution graphics
40 GR: REM Turn on double lo-res mode

You can then use the standard lo-res commands (PLOT, VLIN, HLIN,
COLOR=) to draw, with an available drawing area of 80 columns and 40
or 48 rows.  The colours are identical to standard lo-res.

I think the SCRN function doesn't work properly in double lo-res.
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand