Wanted: Hercules Graphics Library

[Hans Ruegg]

Since PB 3.5 does no longer support Hercules adapters, are the corresponding
libraries available separately? I know these systems are obsolete now, but I
happen to have an older PC with a Hercules adapter which is still in use
(mainly to test programs for compatibility with older systems). I found that
in PB 3.5 not even page switching in Text mode is supported (SCREEN 0,,7,0
caused an "Illegal Function call" on the Hercules system).
As this is not intended for programs for distribution, I am not interested in
buying an additional product, but perhaps there is a way to make the libraries
available which provided Hercules support for former versions of PowerBasic?

Hans Ruegg

[Mel Bishop]

I don't know if any libraries are still available for the
Hercules adaptor. If you can't find any, you may want to try
the various functions of interrupt &h10 to switch to different
video modes.


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[Tony Jones]

There is a 3rd party product called PB 3 Toolkit that has support for the Hercules adapter. You can find more info on it at: http://www.infoms.com/pb3tkit.htm

Or, as Mel already suggested you may want to check out the video interrupt and "roll your own" routines.


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Tony Jones
PowerBASIC Staff

[Hans Ruegg]

Thank you for the hints... although I am not sure if I want to buy
an entire toolkit just for testing programs on my Hercules. Probably
I will have to program the basic routines by myself. But I found that
Hercules stores graphics in a rather strange way in memory: the first
line of pixels is at the beginning of the video segment, the second at
offset &H2000, the third at offset &H4000, the fourth at &H600, and
the fifth line is back at offset 90. So programming this could be a
little awkward.
(Sorry for bothering you with details about this old system...!)

Hans Ruegg


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[Mel Bishop]

You are not "bothering" anybody with details. It's the details
are are always the resolution to any problem.

Depending on what app you are writing, I don't see where
Hercules stores its graphics matters. The program and/or O/S
should automatically adapt and display your graphics accurately.

Wouldn't hurt a thing in the world to write a small test program
using interrupt 10h and see what shakes loose.

Cheers



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[Hans Ruegg]

OK, so I will go on with some more details The only
Interrupt 10h functions I could use with the Hercules are 0Ch
(Write one graphics pixel) and 0Dh (Read one graphics pixel).
Programming graphics drawing them pixel by pixel using these
functions would be very slow. - I found some advanced functions
related to a TSR called "Hercules GRAFIX" (including drawing
rectangles, circles, etc), but I do not have any idea where to
get that program. Unless I find it, I would still have to write
the images directly into memory for reasonable speed. (The system
in mention works with a 80286 processor at 13 MHz.)

Hans Ruegg.

[Tom Hanlin]

The Hercules goes well back into the early days of IBM-type PCs.
For technical and political reasons, it does not include BIOS
support. As it emulates an MDA monochrome display adapter, you
can use its MDA-style text handling through normal methods. If
you want access to anything fancier, it's up to you to program
the hardware directly, or obtain the appropriate routines from
someone who has already done this work.

It should be possible to find documentation and examples of the
required techniques with a little searching of the Web. Be aware
that you will need to use at least a little assembly language if
you plan to write your own Hercules routines.

The only libraries I know of that support Hercules graphics are
commercial products. I believe Information Management Systems has
several such products ( www.infoms.com ). If you're aiming at fancy
graphics, I'd see if Fastgraph will do the job ( www.fastgraph.com ).

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Tom Hanlin
PowerBASIC Staff