Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!orca!mesa!rthomson
From: rthomson@mesa.dsd.es.com (Rich Thomson)
Newsgroups: comp.windows.x.motif
Subject: Re: XmNexposeCallback -- How do I send my own?
Message-ID: <1991Apr29.040007.11132@dsd.es.com>
Date: 29 Apr 91 04:00:07 GMT
References: <1991Apr29.025823.7094@ux1.cso.uiuc.edu>
Sender: usenet@dsd.es.com
Reply-To: rthomson@dsd.es.com (Rich Thomson)
Distribution: local,world,all
Organization: Design Systems Division, Evans & Sutherland, SLC, UT
Lines: 37
Nntp-Posting-Host: 130.187.85.21

In article <1991Apr29.025823.7094@ux1.cso.uiuc.edu>
	CWIKLA@uimrl7.mrl.uiuc.edu (John/Consultant) writes:
>	I basically have a drawingarea widget that at some point I need
>the whole thing redrawn.

Try the following piece of code:

    Widget da;
    XmDrawingAreaCallbackStruct da_struct;

    da_struct.reason = XmCR_EXPOSE;
    da_struct.event = (XEvent *) NULL;
    da_struct.window = XtWindow(da);

    XtCallCallbacks(da, XmNexposeCallback, (XtPointer) da_struct);

If some cosmological aligning of the planets prevents this from
working, try:

    XClearArea(XtDisplay(da), XtWindow(da), 0, 0, 0, 0, True);

This will clear your window and generate an expose event.  The first solution
looks more complicated, but is really preferred because it doesn't
actually require a round trip to the server as in the second example.
The round trip happens because you request the clear, then receive the
expose event from the server, while the first doesn't have to wait for
the expose event to arrive before it starts redrawing.  Alternatively,
if you neeed the window cleared, but don't want to wait for the expose
event, set the last parameter to False in the XClearArea call (or use
XClearWindow).

							-- Rich
-- 
  ``Read my MIPS -- no new VAXes!!'' -- George Bush after sniffing freon
	    Disclaimer: I speak for myself, except as noted.
UUCP: ...!uunet!dsd.es.com!rthomson		Rich Thomson
ARPA: rthomson@dsd.es.com			PEXt Programmer