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From: gtc@cup.portal.com (greg t chalfin)
Newsgroups: comp.windows.x
Subject: XtRealizeWidget() - Why does it work as it does?
Message-ID: <30684@cup.portal.com>
Date: 11 Jun 90 02:40:57 GMT
Organization: The Portal System (TM)
Lines: 19

I'm trying to understand how XtRealizeWidget() works, and something
seems strange about it.  (I'm probably missing something.)

What's confusing me is the sequence of activities when realizing
a composite widget.  The fcn that actually does the work, RealizeWidget(),
is recursive, and it walks down the widget tree from parent to child.
It seems to do a lot of stuff on the way down, but not actually map
anything.  It maps on the way back up, as the recursive calls return.
This means it maps children first and ancestors later.  Which means
you first draw all the children on the screen and then draw the parent
_around_ them.  But this doesn't seem sensible, as it puts a big
burden on the drawing software (or hardware), since the parent has
to be drawn as a lot of little pieces to avoid overwriting any children.

Like I said, I'm probably missing something.  Can anybody tell me what?

Thanks in advance for any hints.

---Greg