Le samedi 5 mai 2007 00:48, Kevin DeKorte a écrit :
> Hi,
>
> I have a situation where I need to highlight an eventbox when a user
> enters it and unhighlight it when the users leaves. I'm using this code
> but the color I'm drawing in the leave_button_callback is always wrong
> and varies from run to run with the program. Any ideas what I am doing
> wrong. I was looking for a XOR option or something but I don't see it.
>
> gboolean enter_button_callback (GtkWidget *widget, GdkEventCrossing
> *event, gpointer data)
> {
> GdkGC *gc;
> gc = gdk_gc_new(widget->window);
> gdk_draw_rectangle(widget->window, gc, FALSE, 0, 0,
> widget->allocation.width-1,
> widget->allocation.height-1);
> gdk_gc_unref(gc);
>
> return FALSE;
> }
>
> gboolean leave_button_callback (GtkWidget *widget, GdkEventCrossing
> *event, gpointer data)
> {
> GdkGC *gc;
> GdkGCValues v;
> GdkColor color;
> GdkColormap *map;
>
> gc = gdk_gc_new(widget->window);
> map = gdk_gc_get_colormap(gc);
> gdk_gc_get_values(gc,&v);
> gdk_colormap_query_color(map,v.background.pixel,&color);
>
> gdk_gc_set_foreground(gc,&color);
>
> gdk_draw_rectangle(widget->window, gc, FALSE, 0, 0,
> widget->allocation.width-1,
> widget->allocation.height-1);
> gdk_gc_unref(gc);
> return FALSE;
> }
You should never draw anything in an enter/leave callback, but only in an
expose event. Also note that creating/destroying a GC each time you draw it
is very slow, so you should do something like this instead:
enter_button_callback()
{
gtk_widget_set_state(widget, GTK_STATE_PRELIGHT);
/* not sure this is required, as it's maybe called by set_state? */
/* you may use gdk_window_invalidate_* instead for better performances,
* see the docs for more infos */
gtk_widget_queue_draw(widget);
}
leave_button_callback()
{
/* same with GTK_STATE_NORMAL */
}
expose_button_callback()
{
gdk_draw_rectangle(widget->window, widget->state->fg_gc[widget->state],
...)
}
--
Cédric Lucantis
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