help w/drawing, bitmaps

[spector@cs.UMD.EDU (Lee Spector)]

(Warning: These are the questions of a mac-low-level-programming novice who
doesn't have Inside Macintosh!)

I have a window into which I draw a scene, using calls to #_PaintRect.
Since the scene is mostly white, I first #_EraseRect the whole thing;
painting everything including the white is much slower.  The scene is
animated (slowly and simply), and of course, the erasures at the start
of every update create an annoying flicker.

I guess that the thing to do is to draw into some sort of offscreen
buffer (another view? a subview?), and then to copy (how fastest?) the 
result into the window.  Although I'm sure this is a common situation,
I didn't see any hints in the manual, so I thought I'd ask if there an 
obvious, simple way to do this that everyone uses.

I'm also curious about bitmaps: the functions documented in the MCL manual
don't seem capable of accomplishing anything without leaving the high-level
lisp interface.  You can make bitmaps and copy stuff between bitmaps, but I 
don't see how you get anything into or out of them - either to/from normal 
lisp data structures or to/from views.  Is there any way to use them without 
delving into Inside Macintosh and using low level record references?
I couldn't find any use of bitmaps in the Examples folder...  I have the
feeling that I'm missing something very obvious.

Thanks for any help you can provide, -Lee (spector@cs.umd.edu)