Re: "undrawing" a line

[Pavel Cisler <pavel eazel com>]

Davina Armstrong wrote:
> 
> Pavel Cisler wrote:
> >
> > Davina Armstrong wrote:
> > >
> > > I posted earlier that I was trying to draw decorations around a GtkLabel
> > > (which is actually part of a composite widget I wrote that packs a
> > > GtkLabel and GtkEntry into a GtkHBox), which I've done successfully -
> > > thanks.  The idea is that I want the decorations to be drawn when
> > > MyWidget gets focus, and "undraw" them when it loses the focus.  I wrote
> > > the following draw_focus function, which is called from
> > > my_widget_focus_in() and my_widget_focus_out():
> > >
> > > static void my_widget_draw_focus(GtkWidget* widget)
> > > {
> > >     g_return_if_fail(widget != NULL);
> > >     g_return_if_fail(IS_MY_WIDGET(widget));
> > >
> > >     if (GTK_WIDGET_HAS_FOCUS(widget)) {
> > >         /* draw the decoration */
> > >     } else {
> > >         gtk_widget_draw(widget, NULL);
> > >     }
> > > }
> > >
> > > The decorations draw when MyWidget gets focus, but don't go away when it
> > > loses the focus.  I've verified that gtk_widget_draw() is being called.
> > > Can anyone tell me what I'm doing wrong?
> > >
> > > Thanks!
> > > Davina
> >
> > Davina,
> >
> > My guess is that the extra decorations don't go away because the
> > gtk_widget_draw doesn't erase any of the backgrounds your decorations
> > are drawn on -- they normally come erased for you in the exposure
> > callback. You could easily verify this by de-focusing your widget and
> > causing it to redraw by invalidating it by another window. The part that
> > you invalidate should redraw without the decorations.
> >
> > Pavel
> 
> Pavel -
> 
> I'm sorry it has taken so long to check this.  You are right, covering
> it with another window does cause the decorations to disappear, but I
> don't know how to invalidate it in code.  Can you (or anyone else)
> please help?
> 

Davina,

You could do that a number of ways. gtk_widget_queue_draw_area will
probably be the best in your case - you would pass it the rectangle
containing the decoration you want to undraw.

Pavel