A83: Partial screen draws

To: assembly-83@lists.ticalc.org
Subject: A83: Partial screen draws
From: "Jonathan Wang" <jwang@isb.bj.edu.cn>
Date: Sun, 11 Jan 1998 20:14:56 +0800
Comments: Authenticated sender is <jwang@fred.isb.bj.edu.cn>
Reply-To: assembly-83@lists.ticalc.org


Okay, I know that I can draw a picture to the screen by doing:

 ld hl,repback
 ld de,plotsscreen
 ld bc,768
 ldir
 call _grbufcpy_v

where repback is the name of an asm picture converted by pic83.  My 
question is, what does each line do?

Also, can I just draw part of the screen.  For example, say I have a 
screen like this:

|------------------------------------------------------|
|             |                                        |
|             |                                        |
|             |                                        |
|             |                                        |
...

and the left side is a toolbar, and the right side is the main 
screen.  Can I just draw parts of the screen so that the toolbar 
stays the same, while the main screen is updated?  It is kind of 
wasteful to redraw the entire screen when I only need to update small 
portions.



Jonathan Wang
jwang@isb.bj.edu.cn
jonathan_wang@hotmail.com

Come visit my home page:
http://www.htmlinfo.home.ml.org/

Quote of the day:

     Virtue has never been as respectable as money.
                                - Mark Twain

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