on 15/2/2001 3:06 PM, Paul Bruneau at paul_bruneau@... wrote:

> Hi everyone-
> 
> I am 100% certain that I have always gone about screen refreshing the
> wrong way. I won't go into detail, but basically, when the user does
> something that I figure should warrant a refresh, then I call my refresh
> routine. 
> 
> I have read enough over the last couple years that I have figured out
> that I should let the OS decide when something needs to be refreshed.
> That is fine, but there are cases, where I need to say, redraw something
> after a user changes a menu item. The OS won't know it, but my program
> will. So I guess I am supposed to manually "invalidate" the area of the
> screen that needs the redraw, then the system will go "hey, that area
> needs to be redrawn" and will send the proper event to my program to do it.

Each to his own, but I've never bothered to work out which bit of the screen
needs refreshing. I just redraw the whole lot. Given the speeds of most
Macs, coupled with the speed of the graphics cards, I don't believe that the
overhead of just drawing part of the screen is worth the effort. Maybe on a
128K Mac, but these days .... ?

I should say that I always refresh the screen from a gWorld, though.

Phil.