LCDSAV.DOC (C)1988 James Yi 73327,1653

LCDSAV.200 is a machine language routine that you can LOADM and CALL from 
BASIC.
With it you can save and load the 240 by 128 pixel screen image to either
 5200 bytes text file, or 3840 bytes compressed binary file.
The text file format can be uploaded and downloaded with TELCOM.

LCDSAV.200 is downloaded as a Basic prgram listing.  Running it creates
LCDSAV.CO.
LCDSAV.CO is 321 bytes long and loads at 63580, the altLCD buffer area.

To use it in a Basic program, first LCDSAV.CO has to be LOADM'ed.
Then CALL 63580,MODE,VARPTR(F$).
MODE is either 0 for Load, to recreate the screen image from an image file,
or 1 for Save, to save the picture to an image file.
F$ is the name of the image file.  It must have either .DO or .CO extension.
The binary(.CO extension) file's loading address is set to 57260.
You do not have to CLEAR the HIMEM when loading/saving to a .CO file, since 
LCDSAV reads and writes directly to the .CO file, without loading it into 
HIMEM.  That also means that you can run other .CO programs safely in HIMEM 
while using LCDSAV.  But LCDSAV is loaded in altLCD, so you should be careful 
about using it with other .CO programs that run in altLCD.

LCDSAV has built in error checking for memory full condition, invalid file name
/type, and non-image file, so there's no way you can do damage by specifying 
wrong parameters.

If you save to an already existing image file, it is simply updated.

Here are some sample calls:

10 'This one saves the screen to a .CO file.
20 LOADM "LCDSAV"
30 FC$="IMAGE1.CO"
40 CALL 63580,1,VARPTR(FC$)
50 END


10 'This one loads the screen from an existing .DO image file.
20 LOADM "LCDSAV"
30 FD$="IMAGE2.DO"
40 CALL 63580,0,VARPTR(FD$)
50 END


10 'This one converts a .CO image file to .DO image file,
20 'by loading the image from a .CO file, then saving it to a .DO file.
30 LOADM "LCDSAV"
40 FC$="IMAGE1.CO":FD$="IMAGE1.DO"
50 CALL 63580,0,VARPTR(FC$)
60 KILL FC$:'Throw away original .CO
70 CALL 63580,1,VARPTR(FD$)
80 END


For screen dumping to a dot-matrix printer, look in DL10 for:
 GRDUMP.200, for normal size prints,
 or LCDPRT.200 for double size.

	<END of DOC>