beginners question: bitmaps &c.

[pberck@kub.nl (Peter Berck)]

Hi,

I have an applications which draws a graph in a window everytime
the window needs updating. Since this is slow, it occured to me that
it would be easier to draw the picture on a bitmap, and copy-bits the
thing to my window. 
I looked in the manual, and the there are only a few lines on bitmaps
in the appendix-b. (i.e. how to create one, and how to copy-bits). 
How do I draw into a bitmap? Should I perhaps do it in a different way?

thanks,
-peter