Category : Printer + Display Graphics
Archive   : CGA2VGA.ZIP
Filename : CGA2VGA.DOC

CGA2VGA (c) 1988 Lawrence Gozum & Marvin Gozum
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User Manual

DISCLAIMER

This product is distributed AS IS. The authors specifically disclaim
all warranties ,expressed or implied, including ,but not limited to,
implied warranties of merchantability and fitness for a particular
purpose with respect to defects in the diskette and documentation, and
program license granted herein, in particular, and without limiting
operation of the program license with respect to any particular
application use or purpose. In no event shall the authors be liable
for any loss of profit or any other commercial damage including but
not limited to special,incidental, consequential or other damages.
You are NOT licensed to use or distribute this program in states where
this disclaimer is not considered in effect.


LICENSING AGREEMENT

You may use this program on a TRIAL BASIS only; this means that you
may freely evaluate the usefulness of this program for a reasonable
period. Should you find this program useful, you must register by
sending in registration form with a check payable to Marvin Gozum in
the amount of $8.95. You will then be provided with a personalized
copy of this utility. As a bonus, you will receive the latest version
of VGACAD (VGA Computer Assisted Design).

You may freely distribute copies of this program in its UNMODIFIED
state provided you do not include it in other software packages, with
the exception of distributing it as part of a bundle of Public Domain
or shareware programs on a single diskette. In addition you may not
charge more that $3.50 for copying and/or distributing this program in
the absence of any recognized Users Group guidelines.


INTRODUCTION

VGA (Video Graphics Array) is now the de facto video graphics standard
in the IBM PS/2 series (Model 50,60 and 80). MCGA (Multi-Color
Graphics Array) is supported by Model 30; I'm not sure what Model 25
supports. Although VGA has a 640x480 pixel mode, it only supports a
maximum of 16 colors - ala EGA (Enhanced Graphics Adaptor). The MCGA
256 color mode with a resolution of 320x200 pixels provides near-
photographic quality as well maintains a broad spectrum of
compatibility with the new PS/2 machines since it is not only the
lowest common denominator (in graphic modes) but it provides the most
astounding results.
















CGA2VGA is a terminate-stay-resident (TSR) utility that allows you to
capture CGA 4-color graphic screens (even 2 color screens) and
translate then into VGA and MCGA screens in MCGA 256 color mode and
save the screen in a "Bloadable" format. Once saved you can edit your
old pictures and increase their color range wiht your favorite paint
or CAD program (VGACAD is particularly designed to do that task).

Since the MCGA 256 color mode uses 64K of contiguous memory without
bit-planes, it makes it possible for you Bsave and Bload these
screens without much of a fuss, regardless of the BASIC program or
BASIC compiler you are using. Thus, you will be able to make dazzling
presentations or slideshows effortlessly using digitized pictures that
you have downloaded from various BBSs or screens designed with
different painting or CAD programs.


HOW TO USE CGA2VGA

Simply run CGA2VGA before entering your painting/CAD or digitized
picture viewer. After it is loaded, press and your current
screen will be saved to your default directory and drive. The first
time you run the program it will save your screen to a file labelled
MCGASCRN.000 and will increase thereafter up to .999. If CGA2VGA
continues to be resident, the latest file number will be incremented,
regardless of the screens captured in the default directory or drive.
If there is an existing MCGASCRN.xxx, then it will increment to the
next higher number. That is all there is to it. You can use your
favorite memory managers to remove this TSR or reboot if you want to
release it from memory.


REQUIREMENTS

It goes without saying that you MUST have a VGA adaptor or MCGA
adaptor (BIOS compatible at the very least) present and an analog or
multi-frequency monitor as well. This TSR uses 64K of your available
memory; therefore your application must have enough free memory along
with your other TSRs for it to function properly.

If you are in DOS, there is a good chance that the program will cause
your system to hang. Make sure you invoke this TSR only in your
application as well as making sure that you are in the right screen
mode. Later versions should correct this little irritant.

QuickBASIC 4.0 users should be careful of calling this TSR when in the
program development/editor environment. The program will cause your
system to hang when invoked during a QB 4.0 development session since
it manages the memory and video modes to run several modules. I hope
to correct this in later releases.

















BLOADING FROM BASIC

The following lines will load one of the captured screens from
QuickBASIC 4.0


Screen 13: 'init MCGA 256 color mode
DEF SEG=&HA000: 'point data segment to
'screen buffer A0000H
Bload "MCGASCRN.000",0: 'load the screen
DEF SEG : 'restore data segment


If you are using a QuickBASIC 1.0, 2.0 or 3.0, I have included
VGAMODE.obj which is an object file created with MASM 4.0 which you
can include in your UserLib.exe thorough BUILDLIB.exe. VGAMODE.obj is
a BIOS compatible assembly routine which you can use to call even the
more exotic graphic modes that your compatible VGA card can handle (if
you are using one). The following lines will perform just as well as
the listing above.


Call VGAMODE(&H13): 'init MCGA 256 color mode
DEF SEG=&HA000: 'point data segment to
'screen buffer A0000H
Bload "MCGASCRN.000",0: 'load the screen
DEF SEG : 'restore data segment


REGISTRATION

Send the registration form or a card stating your full name and
address and a $8.95 check made payable to:

Marvin Gozum
2 Independence Place Apt. 303-2
6th & Locust Street

Philadelphia, PA 19106