[comp.sys.ibm.pc] displaying EGA and VGA images

jeg@ptsfa.UUCP (John Girard) (01/20/88)

I am looking for advice on how to call EGA and VGA images
up on the screen.  Forays through the manuals and book
stores have been less than successful.

Specifically, I'd like to have some code examples in 
BASIC and C of how to load EGA and VGA images from files
to the screen.  I'd also like to know "which" file formats 
are the best to use.  There seem to be a lot of different
ways to save images invented by different graphics packages.

Please post to the net ...

	       Thanks!  
		  John Girard
		  {ihnp4,cbosgd,pyramid}ptsfa!jeg
		  415-823-1961

jru@etn-rad.UUCP (John Unekis) (01/22/88)

In article <4032@ptsfa.UUCP> jeg@ptsfa.UUCP (John Girard) writes:
>I am looking for advice on how to call EGA and VGA images
>up on the screen. 

I am not sure about VGA, but the EGA card has up to 256K of RAM which
is mapped as 4 bit planes, each 64K in size, and all beginning at address
A000:0000 hex(in display mode 15). The 640 x 350 bitplanes are adressed 
as 350 consecutive lines of 80 bytes each. A number of special purpose
registers have to be set up for both reading and writing the memory, all 
of which is documented in totally incomprehensible form in the ibm tech
reference manual for the EGA.

The easiest way to display images on EGA is simply to buy a package that 
supports such displays. Media Cybernetics Image-Pro is one such package,
available from Media Cybernetics at (301)495-3305.  Another package, which
includes both software and a half-slot PC card, allows the EGA controller
to display real(not dithered) images in mono and color. This package is
the CLARITY1 by MASER Research, and is available from SEFCO (818)765-8882.