[Coco] Alternate font sets

[tim lindner]

On Fri, Aug 26, 2016 at 6:54 AM, Ron Klein <ron at kdomain.org> wrote:
> Hello everyone,
>
> Is it possible load alternate font sets for the Coco that are compatible
> with many of the text adventure games out there?  I'm also looking to see
> if there are any 80 column font sets available for the Coco 3.
>
> If so, how is this done?  A binary EXEC that gets loaded?  Not sure how
> this would work.

For games and programs that use the graphics screens, there is no
common scheme for presenting text. Everyone rolls their own routines
to display text, so there is no point in discussing anything in
general.

As far as text screens, let us discuss the CoCo 1 & 2 first. The VDG's
default text mode uses a font encoded in the chip that is not
modifiable. There is a special mode to use an external character ROM.
No provisions have been made on the motherboard to accept such a ROM,
but various people have successfully hack one in.

The situation on the CoCo 3 is similar. For the most part when
software uses graphics screens to present text, they do so using their
own unique software routines. There is a font located in the BASIC ROM
that has a copy of the text mode font. BASIC uses this copy for it's
HPRINT command to draw text on a graphics screen.

I don't believe there is anyway to change the text mode font with the
CoCo 3's GIME chip.

Under OS-9, on the CoCo 3, there is a standard way to draw text on
graphics screens. If programs use this facility, then different fonts
can be loaded and used.





-- 
--
tim lindner

"Proper User Policy apparently means Simon Says."