Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!xanth!nic.MR.NET!umn-cs!randy
From: randy@umn-cs.CS.UMN.EDU (Randy Orrison)
Newsgroups: comp.windows.x
Subject: How do I draw on a widget?
Keywords: novice excuse ignorance
Message-ID: <10461@umn-cs.CS.UMN.EDU>
Date: 16 Dec 88 03:36:12 GMT
Reply-To: randy@umn-cs.cs.umn.edu (Randy Orrison)
Organization: Chemical Computer Thinking Battery, St. Paul, MN
Lines: 53

What kind of Widget should I use to draw on, and how do I do it?  I'm
currently trying to use a staticraster widget, and am getting the
display and window with the XtDisplay and XtWindow calls, but when I
call XDrawRectangle I get an X Error: parameter not a Pixmap or
Window.  The thing that bothers me is that this error does not occur
at the time of the XDrawRectangle call, but later.  I don't know when,
really.  I'm sure that this info is useful in some way:

| X Error: parameter not a Pixmap or Window
|   Request Major code 67 
|   Request Minor code
|   ResourceID 0x0
|   Error Serial #41
|   Current Serial #56

but it doesn't help me any.  Here's the code that creates the widget:

|   XtSetArg (arg[0], XtNheight, (XtArgVal) HEIGHT);
|   XtSetArg (arg[1], XtNwidth, (XtArgVal) WIDTH);
|   XtSetArg (arg[2], XtNsRimage, (XtArgVal) NULL);
|   fu = XtCreateManagedWidget ("box", XwsrasterWidgetClass,
|			        rgber, arg, 3);

and here's the code that trys to draw on it:

|void
|putbox (wid, x, y)
|   Widget	wid;
|   int		x, y;
|{
|   Window	drawwin = XtWindow (wid);
|   Display	*dpy	= XtDisplay (wid);
|   XGCValues	gcv;
|   GC		gc;
|
|   gcv.foreground = BlackPixel (dpy, DefaultScreen (dpy));
|   gcv.background = WhitePixel (dpy, DefaultScreen (dpy));
|   gc = XtGetGC (wid, (GCForeground | GCBackground), &gcv);
|
|   XDrawRectangle (dpy, drawwin, gc, x-2, y-2, 5, 5);
|}

The routine putbox is called with 'fu' from the bit of code above that
creates the widget.  What am I doing wrong?  Please take into account
that I have no idea what I'm doing anyway...

	Thanks for any and all help!

		-randy
--
Randy Orrison, Chemical Computer Thinking Battery  --  randy@cctb.mn.org
(aka randy@{ux.acss.umn.edu, umn-cs.uucp, umnacca.bitnet, halcdc.uucp})
Lie: A very poor substitute for the truth, but the only one discovered
to date.