COMPLETELY amazed! How is it done?

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4 total messages Started by Alan Mead Thu, 21 Jan 1993 06:56

#7629

Author: Alan Mead
Date: Thu, 21 Jan 1993 06:56

15 lines
968 bytes

I thought I knew a thing or two about how VGA fonts work on the IBM
PC...

Then I happened to invoke a little programmer's tsr while in WordPerfect
5.1 .  All the letters that the tsr used were strange greek, foreign,
etc, symbols.  (This is while the prefectly normal charscters show on
the screen.)

I know how to change a font, but how do you make more than 256
different chars appear on the screen?  And why would WordPerfect remap
the normal a..zA..Z to something else?

Thanks.  I'll be able to sleep again when I know.

-alan

Re: COMPLETELY amazed! How is it done?

#7631

Author: Jeremy Brown
Date: Thu, 21 Jan 1993 12:22

49 lines
1720 bytes

amead@s.psych.uiuc.edu (Alan Mead) writes:

>I thought I knew a thing or two about how VGA fonts work on the IBM
>PC...

>Then I happened to invoke a little programmer's tsr while in WordPerfect
>5.1 .  All the letters that the tsr used were strange greek, foreign,
>etc, symbols.  (This is while the prefectly normal charscters show on
>the screen.)

>I know how to change a font, but how do you make more than 256
>different chars appear on the screen?  And why would WordPerfect remap
>the normal a..zA..Z to something else?

>Thanks.  I'll be able to sleep again when I know.

>-alan

Hi All,

One way is to tell the EGA/VGA card that when the intensified attribute
is set it should display the character from the second character set.

  AX = 1103      ; intensified == 2nd character set
  BL = 04
  INT 10

  AX = 1000      ; Enable all planes
  BX = 0712
  INT 10

To disable (ie intensified is really intensified)

  AX = 1000
  BX = 0F12
  INT 10

If you can find a copy "PC Magazine September 16, 1986" had an articule
by Charles Petzold explaining the above techniques.

Hope this helps,

Jeremy

--
Jeremy Brown                      EMAIL: jb@materna.de
Dr Materna GmbH                   Tele : +49 231 5599301
Vosskuhle 37                      Fax  : +49 231 5599100
4600 Dortmund 1  Germany          Home : +49 231 416655

RE: COMPLETELY amazed! how is it done

#7666

Author: vdkamp
Date: Fri, 22 Jan 1993 09:15

23 lines
1077 bytes

In article <C16zAy.KIz@news.cso.uiuc.edu>, amead@s.psych.uiuc.edu (Alan Mead) writes:

[.... stuff deleted....] 

> I know how to change a font, but how do you make more than 256
> different chars appear on the screen?  And why would WordPerfect remap
> the normal a..zA..Z to something else?

The EGA/VGA Character generator can display simultaniously 512 different 
characters on your screen.

Russian (Cyrillic fonts) people don't have a..zA..Z characters so they
remap.

> 
> Thanks.  I'll be able to sleep again when I know.

Sleep well....

Bob.

VDKAMP@RULLF2.LeidenUniv.nl

Re: COMPLETELY amazed! How is it done?

#7668

Author: Kyle Anthony York
Date: Fri, 22 Jan 1993 15:19

16 lines
1067 bytes

In article <C16zAy.KIz@news.cso.uiuc.edu> amead@s.psych.uiuc.edu (Alan Mead) writes:
>I thought I knew a thing or two about how VGA fonts work on the IBM
...
>
>different chars appear on the screen?  And why would WordPerfect remap
>the normal a..zA..Z to something else?
>
>Thanks.  I'll be able to sleep again when I know.

you can load a seconds 256 character font using the various BIOS load font
functions, then change bit 7 of the attribute from the standard
'blink' to 'use alternate font'. sorry this is so vague, i haven't done it
for several years (since EGA). if you need more specifics let me know

--kyle

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