Re: drawing in a not-callback-function

["Brian J. Tarricone" <bjt23 cornell edu>]

Daniel Dieterle wrote:
> Hi,
>
> i'm just beginning to collect some experience with gtk+ and glade.
>
> My goal is to draw regularly a circle on an other position. I think the
> right way doing this, is to use a timer-function. It should be something
> like this:
>
> gint draw_satellite( gpointer data )
> {
> gdk_draw_points( widget->window, gc_earth, (GdkPoint
> *)&orbit_satellite[j], 1 );
>         satellite_position++;
> }
>
> gtk_timeout_add( 100, draw_satellite, NULL );
>
>
> My problem is, that i can't imaging, how i can access the
> "widget-window".
> In a normal callback-function i get this value by a call of reference.

In general, you shouldn't be doing any drawing anywhere except in your 
widget's expose handler.  If you want to trigger a draw, you'd use 
gtk_widget_queue_draw_area() (or gtk_widget_queue_draw() to just trigger 
a redraw of the entire widget).

For the expose handler, if you have your own widget implementation, 
you'd override GTK_WIDGET_CLASS(your_widget_class)->expose_event in your 
widget's class_init() function, or, if it's not your own widget, you can 
connect to the widget's "expose-event" signal.  Do your drawing in that 
handler.

        -brian