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      DOCUMENTATION FOR FILES TURBWIN3.INC AND OSBTWIN2.INC
                 (c) Copyright 1986 Claude Ostyn

A.  DESCRIPTION

These are "include" files for Turbo Pascal 3.xx 
running under CP/M 80.

The files contain routines to emulate the Window procedure 
described in the Turbo Pascal manual in the "IBM PC Goodies" 
section.   Window allows you to define a window anywhere on your 
screen.  All writing will then take place within the window only, 
and when the window becomes full the text within it will scroll 
without affecting the rest of the screen.  Other screen command 
such as GotoXY, ClrScr and ClrEol will work within the window 
only, so that for instance GotoXY(1,1) will place the cursor at 
the top left corner of the window.

B.  FEATURES 

Functions WhereX and WhereY return the current position of the 
cursor (position where the next character will appear).

The following procedures have been added:

Procedure InitVideo 
-- must be called to initialize the window emulator.  Attempts to 
call any of the other functions without having called InitVideo 
earlier may cause impredictable results.

Procedure DeInitVideo
-- restores the Turbo video interface as if nothing had happened.  
You must call this procedure if you are compiling your program in 
memory and you want to run it more than once without recompiling.  
If you don't call DeInitVideo at the end of your program, Turbo 
will detect an anomaly and exit to CP/M the second time you try 
to run the program.

Procedure FullScreen
-- Resets the current window to encompass the full video screen.

Procedure DrawBox(Top left corner, Bottom right corner) 
-- Draws a box, using graphic characters if they are available.

Procedure MakeWindow(Top left corner, Bottom right corner)
-- Draws a box and sets up a window to fit inside the box. 

Procedure SetVideo(Video effect)
-- Allows you to set more than one video attribute.  Works 
whether or not InitVideo has been called.  See limitations below.

When a new window is declared, the old window parameters are 
forgotten.

C.  LIMITATIONS

GotoXY does not check the validity of the parameters you pass to 
it.  If you try to send the cursor outside the window (X > width 
or Y > height), it may land anywhere on your screen (the standard 
Turbo GotoXY procedure has the same limitation).

If your computer uses memory-mapped video (like the Osborne 1),
you will be able to do very fast scrolling and window blanking.
If you don't use memory-mapped video, scrolling and blanking will 
become proportionnally much slower as the windows become larger, 
and you will loose 2K for the scroll memory array.

However, if you make your text scroll, the video attribute (dim, 
underline, etc.,) will not necessarily follow the text or may end 
up in different parts of the window.  In short, if you're using 
special effects, don't scroll.

On many terminals, the whole screen scrolls up when you put any 
character in the lower right corner of the screen.  This is a 
feature, not a bug, but it will efectively prevent you from 
including that corner with DrawBox or MakeWindow.

My windows behave a little differently.  You can put a character
in the lower right corner without forcing a scroll.  Scrolling
will not happen until you try to write a character PAST that
position.

D.  USING WITH YOUR PROGRAM

To use, edit a copy of the file TURBWIN3.INC as required for your
system (see the comments in the file TURBWIN3.INC).  If you do
not edit the file, it will be assumed to be for a terminal
compatible with the ADM-3A, Osborne 1, etc., or Hazeltine 1500,
but NOT memory-mapped.

On the other hand, you might use the file OSBTWIND.INC which is
compatible ONLY with the Osborne 1.

Put the edited copy of the .INC file on your default disk drive.
At the beginning of your Turbo Pascal program, add the line:

     (*$I FILENAME.INC *)

(of course, you must replace "FILENAME.INC" with whatever name
you used for your edited file)

TW3DEMO.PAS and OSTWDEMO.PAS are two short files which you can use
to test your edited version.  TW3DEMO.PAS uses the include file
TURBWIN3.INC and is for most CP/M machines, while OSTWDEMO.PAS
uses OSBTWIND.INC and will run correctly only on the Osborne 1.

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