			Screen.BIN

	Copyright (C) Paul B. Powers, August 18, 1990

	When distributing the screen.bin file this text file,
readme.scr is to be distributed along with it.  This software is
being distributed as Freeware and no payment is charged for its
use or distribution.  The author has made every available attempt
to test this piece of software.  However, the author cannot be
held responsible for any damage, loss or other mishaps as a
result of the usage of this software.


The bin file takes two parameters.  the bin file can be called
with the call command or function - Call or Call() as follows;

	load screen

	* either *
	call screen with <parameter1>, <parameter2>
	* or     *
	memvar = call("screen","<parameter1>,"<parameter2>")

	release module screen

	parameter1 has the following option;
	"W" or "w" - which will write the screen characters and
				attributes to the filename specified in
				parameter2.  Neither write mode will 
				overwrite a file.

	"W-" or "w-" - which will write only the screen characters
				to the file spoecified in parameter2. Neither
				write mode will overwrite a file.

	"A" or "a" - which will only append the screen characters to
				the filename specified in parameter2.  The
				append mode will only concatenate the
				characters to the end of the file specified
				in parameter2.

	"R" or "r" - which will read the file and print it on the
				screen, whether the bin file prints only
				characters or both characters and color
				attributes depends on the size of the source
				file to be read (see chart below).
				specified by

	parameter 2 is the drive:\path\filename of the file that is
to be read, written, or appended.


	You can also use a text editor to make the text file to be
read in.  To do this make sure you use only spaces, don't use any
tabs to fill in blank spaces.  Each row on the screen is expected
to be 81 characters long.  The first 80 characters are expected
to be text characters (i.e. no tabs, use the spacebar to create
blank spaces), on column 81 you are expected to press the enter
key.  If you are in a 25-line mode (Mono, CGA, EGA or VGA) make
sure the text file has 25 lines.  If you are in a 43-line mode
(EGA) or a 50-line mode (VGA) make sure the text file has 43 or
50 lines in it, respectively.  This file format is designed so
that a text editor will be to read a text file that is created by
screen.bin with the "w-" or the "a" option.  To see the type of
file screen.bin creates creates in general see the diagram below.





For writing your own text files to use with screen.bin the format
is as follows:

			text file
1											80  81
|------------------------------------------------------|<cr>/<lf>
|											|
|											|
|		characters go here						|
|											|
|											|
|------------------------------------------------------|
|											|
|											|
|		(optional) attributes go here,			|
|	not used with the "w-" and "a" modes			|
|											|
|------------------------------------------------------|

The "r" option will read in and interpret the file as having
characters only or having both characters and color attributes
based on the size of the specified text file.  The interpretation
will be based as follows:


25-line mode  4098 bytes: (82 bytes/row) * (25 rows) * 2 (for 
			and above		character and color attributes). 
						Why 82 bytes/row instead of 81 is
						that a text  editor will place two
						characters (a <cr> and a <lf>) in
						the file when the [enter] key is
						pressed.  This resultant size will
						actually work out to be 4101
						bytes.  Three bytes are taken off
						the file size in case the last
						<cr>/<lf> and the end-of-file
						marker is not added on.

			2048 to	: (82 bytes/row) * (25 rows). Only 	
			4097 bytes	characters will be read from		
						the specified text file.



43-line mode	7050 bytes: (82 bytes/row) * (43 rows) * 2  Both
			and above		characters and color attributes
						will be read from the specified
						text file.

			3524 to	: (82 bytes/row) * (43 rows).  Only 	
			7049 bytes	characters will be read from the 	
						specified text file.



50-line mode	8198 bytes: (82 bytes/row) * (50 rows) * 2.  Both
			and above		character and color attributes will
						be read from the specified text
						file.

			4098 to	: (82 bytes/row) * (50 rows).  Only
			8197 bytes	characters will be read from the
						specified text file.



Since some people have a "beta" version of this bin file a
listing of the changes and fixes have been provided.

Version 1.1b - Changes and Fixes.

1. Bug fix regarding reading the color attributes.  Reading in a
file
   with color attributes to write to the screen resulted in the
color
   attributes being read in, but shifted one column to the left
on the
   screen.  The text would appear normal on the screen but it's
color
   attribute would appear column to the left of the text.  This
bug
   has been fixed.

2. At the DOS-prompt type "type screen.bin" to see the version
number-
   thanks goes to Keith Mund for presenting this idea to me.


Version 1.2 - Changes.

1. Screen.bin can now be called with the call() function, and
will
   pass back an error/success code to dBASE IV.  The error codes
are
   assigned as follows;

   1: Product is not dBASE IV (you should never see this error
code,
	 let me know if you do).

   2: Lines on screen are not set to 25, 43, or 50.

   3: First parameter was not a "W","w","R","r","A", or an "a".

   4: Unable to open file, the file does not exist, was
previously
	 opened or the path was mispelled .

   5: File is too small to read, for the current line mode.

   6: Unable to position a file pointer for a file read.

   7: Error occured during a file read.

   8: file already exists (happens with the "W","W-","w" or "w-"
	 option).

   9: Unable to create the file (happens with the
"W","W-","w","w-"
	 and the "A" and "a" options).

   A: Unable to position a file pointer for a file write.

   B: Error occured during a file write.

   C: File failed to close.

Version 1.2b - Fixes

1. Minor corrective coding change provided to ensure proper
embedding of carriage return/linefeeds and end of file markers in
the output file.

Version 1.2c - Changes

1. Just a change in what the copyright says when a "type
screen.bin" writes when executed from a dos-prompt.  Nothing else
has changed.



Further Enhancements:

  If you like this piece of software or think it could be
enhanced in a certain fashion please contact him.  Any further
advancement of this bin file will be proportional to it's use AND
the response for enhancement of those who use it.

The author can be contacted by E-mail on the Ashton Tate BBS at;

	1200 BAUD  (213)538-6196

	2400 BAUD  (213)324-2188

	or on Compuserv (for free access use this route), 
	at the "Host Name:" prompt type "ATBBS"
	

	Please leave E-mail for the user name of Plpowers.


Special thanks goes to those who were part of the beta-testing on
this bin file, they are;

Judy Maske
Dan Madoni
Roger Bowman

Thanks very much guys !


And lastly thank you very much, and enjoy !
