[A83] Re: Graph Buffer

To: assembly-83@lists.ticalc.org
Subject: [A83] Re: Graph Buffer
From: Jkhum98@aol.com
Date: Wed, 15 Aug 2001 15:00:56 EDT
Reply-To: assembly-83@lists.ticalc.org

In a message dated 8/15/01 11:45:46 AM Central Daylight Time, 
typerfuture@hotmail.com writes:

> I know that the _grbufcpy_v romcall copy's from the graph buffer to the 
> screen, but how can I write to the Graph-buffer in the first place?
> 
> After looking at a program in AsmGuru I thought it was a mode-flag with
> textwrite (don't know the exact syntax anymore) and I tried this but it 
> didn't seem the make any difference to the program...

When using Vputs-type romcalls, you can do "SET textwrite, (IY+sGrFlags)" to 
have that small-font text be written to the graph buffer, and then copy 
plotsscreen to the LCD with _grbufcpy_v (named _grbufcpy for the 83+).  If 
you want to use TI-OS romcalls to draw points and lines with _IPoint and 
_ILine and such, then you do "RES plotloc, (IY+plotflags)" to have those 
pixels be set to plotsscreen also. You must Reset textwrite before returning 
to the TI-OS or else it wont render correctly in some places, but plotloc 
doesnt seem to matter if its Set/Reset upon leaving. If you are using common 
routines like ION's putsprite, largesprite, and getpix, those will all work 
with the buffer and not send any data to the LCD until you call _grbufcpy.

-Jason Kovacs