🚀 go-pugleaf

jgg@proforma.com (J. G. Gregory) writes:
> Way back when, there was this feature called "instance drawing".  It was  
> documented in the Concepts docs, as well as the function docs.  Now I can't  
> seem to find a description of it, except for the function definitions.  I  

When you use a buffered window, all your drawing goes to the buffer and
isn't immediately visible.  You make it visible by doing a flushWindow,
which copies the changed bits in the buffer to the visible areas of the
screen.

When you turn on instance drawing, you draw directly onto your window's
area on the screen, and the drawing never touches the buffer, so it doesn't
get saved.  It can be used for temporary drawing or animation, but since  
there's no buffering you see the erasures happening and it tends to look
flickery (and to my eye, cheesy and unprofessional)

The basic algorithm looks like this:

PSsetinstance(YES);
while (temporaryAnimation) {
	PSnewinstance();	// erase old instance drawing
	[self drawSomething];	// draw temporary stuff
	}
PSsetinstance(NO);

I suggest you avoid instance drawing, and instead look at Draw or
ScrollDoodScroll's NiftyMatrix to see how to do double buffered animations.

-sam
ps I noticed last night that NiftyMatrix has an error that causes it to cache
its browser incorrectly.  The solution is to remove the call to
convertFromSuperview.

--
Opinions expressed herein are not those of my employer.  They're not even
mine.  They're probably wrong besides.  How did they get in here, anyway?