Re: forcing immediate redraw on widget

[M Santhoff t-online de (Marc Santhoff)]

Am Mo, den 26.04.2004 schrieb Gus Koppel um 23:43:
> Marc Santhoff wrote:
>
> > > > How can the immediate redraw of a widget be forced using GTK+ 1.2?
> > >
> > > I think the following should work in GTK+ 1.2 and 2.x:
> > >
> > >     gtk_widget_queue_draw (widget_to_redraw);
> > >     while (gtk_events_pending ())
> > >         gtk_main_iteration ();
> >
> > Thank you for answering, although after testing this seems to be only
> > one half of the solution.
> >
> > The other half would be to invalidate or mark the widget for
> > redrawing, so that there are events to process. Apparently changing
> > the background color on a widget (hscale in this case) does not do it.
>
> Have you included the first half (the call to gtk_widget_queue_draw ())
> into your test? Just changing simple attributes isn't enough indeed to
> force a widget to be redrawn. gtk_widget_queue_draw () is supposed to do
> excatly what you were suggesting: invalidate the the widget for

Yes, i saw that too late. I should have written that it does not work as
expected.

> redrawing. See:
>
> http://developer.gnome.org/doc/API/2.0/gtk/GtkWidget.html#gtk-widget-queue-draw
> http://developer.gnome.org/doc/API/2.0/gtk/GtkWidget.html#gtk-widget-queue-draw-area
>
> If it still doesn't work using gtk_widget_queue_draw () I suspect either
> a deficiency of GTK+ 1.2 or another bug in your program.

I agree. I've posted the code already, but this is what I'm doing:

// declaring one pointer and two color variables
var
        st      : pGtkRcStyle;
        cola, colp      : TGdkColor;
begin

// and try to switch appearance on a hscale

                { swap the visual focus }
                gdk_color_parse(SPEED_COLOR_ACTIVE, @cola);
                gdk_color_parse(SPEED_COLOR_PASSIVE, @colp);

                st := gtk_rc_style_new ();
                
                if (target = 1) then begin
                        gtk_widget_grab_focus(GTK_WIDGET(scales[1]));

// dereferencing a pointer var like "st->bg[]"                  
                        st^.bg[GTK_STATE_ACTIVE] := colp;

// or'ing together style and new bg change
                        st^.color_flags[GTK_STATE_ACTIVE] := st^.color_flags[GTK_STATE_ACTIVE] OR GTK_RC_BG;
                        gtk_widget_modify_style(GTK_WIDGET(scales[0]), st);

After this I've tried several methods of getting the change visible,
starting without or with a definition in an rc file for testing what
color setting looks good on the hscale.

If there is an other way of changing this color I would be glad, but I
could not find a way to switch the style of a widget between to rc-file
definitons.

The goal is to toggle color schemes for active and passive on two
hscales, that used to set some motor speeds. They're xor working, inly
one active at a time.

Marc