🚀 go-pugleaf

In article <100607@bu.edu> kiki@bass.bu.edu (Keith Baccki) writes:
>
>	Drawing something into the Drawing Area should be a
>trivial task, but nonetheless the following pieces of code
>do NOTHING in the window:
>
>      XtSetArg(...);   /* bunch of these... NOTE: height = 650 */
>                       /*                          width = 400 */
>      ionwindow =XmCreateFormDialog(toplevelshell,"ionwindow",arglist,6);
>      XtManageChild(ionwindow);
>
>      XtSetArg(...);   /* Few more... NOTE: requested height = 460 */
>	               /*                        "     width = 400 */
>      iondrawable = XmCreateDrawingArea(ionwindow,"iondrawable",arglist,4);
>      XtManageChild(iondrawable);
>
>      gcvalues.foreground = BlackPixel(display,DefaultScreen(display));
>      gcvalues.background = WhitePixel(display,DefaultScreen(display));
>
>      gc = XCreateGC(display,XtWindow(iondrawable),GCForeground | GCBackground, &gcvalues);
>
>      XFillRectangle(display,XtWindow(iondrawable),gc,(Position)50,(Position)50,(Dimension)200,(Dimension)200);
>      XDrawLine(display,XtWindow(iondrawable),gc,(Position)
>100,(Position) 100,(Position) 300,(Position) 150);
>      XFlush(display);
>
>Any suggestions? Am I missing something?
>
>
   If this is the exact order of your code, then the problem is that your're
trying to draw into a window (drawable) that hasn't been mapped 
(i.e., realized) yet.  An Expose event is automatically generated (and the
window is erased) when a window is first mapped.  The stuff you drew gets
erased when the DrawingArea is realized.  Add the code that does the 
drawing to an XmNexposeCallback for the DrawingArea and your stuff will
appear in the window every time an Expose event is generated (especially
after the first Expose event).

			- Hope this helps,
			  Paul D. Johnston

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| Paul D. Johnston			|			|	     |
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