Newsgroups:	comp.os.msdos.djgpp
From:	tob AT world DOT std DOT com
Subject:	Re: Allegro question
Message-ID:	<EEKLFM.s6@world.std.com>
Sender:	tob AT world DOT std DOT com (Tom Breton)
Reply-To:	tob AT world DOT std DOT com
Organization:	BREnterprises
References:	<Pine DOT SUN DOT 3 DOT 93 DOT 970806212537 DOT 6848A-100000 AT degobah>
Date:	Fri, 8 Aug 1997 00:59:46 GMT
Lines:	33
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Insomnia <insomnia AT degobah DOT core DOT binghamton DOT edu> writes:
>         This is a VGA issue (including SVGA).  The screen border (the
> displayed portion of the screen that you cannot write your own pixels in)
> is always displayed in color 0 in paletted modes and black in non-paletted
> modes.  Unfortunately, the only way AFAIK to make sure the border is black
> is to rearrange your palette such that color 0 is black.

Not strictly true. The border color can be set exactly the same way that
the 16 colors of the EGA palette can be. Note that I'm *not* talking
about the 256 colors of the VGA palette. The background (like the 16)
can be set to index one of the 256, tho it takes some extra work to make
it look beyond the first 64.

[Credit to Mark Feldman for the following, I believe]

3C0h index 0-Fh  (r/W):  Attribute: Palette
bit   0  (EGA) Primary Blue
      1  (EGA) Primary Green
      2  (EGA) Primary Red
      3  (EGA) Secondary Blue
      4  (EGA) Secondary Green
      5  (EGA) Secondary Red
    0-5  (VGA) Index into the 256 color DAC table.
               May be modified by 3C0h index 10h and 14h.


3C0h index 11h (r/W):  Attribute: Overscan Color Register.
bit 0-5  Color of screen border. Color is defined as in the palette registers.
Note: The EGA requires the Overscan color to be 0 in high resolution modes.


        Tom

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