Re: Mouse Clicks in a Drawing Area

["ldries46" <bertus.dries@planet.nl>]

I now het changed the Add_Events into Set_Events (within the first code 
listing but the result is the same, nothing happens.
I had done it that way before but

http://askubuntu.com/questions/157290/how-to-draw-on-mouse-click-in-gtk-drawingarea-using-pygi

suggested the add_events routine. That code is now

Set_Events(Sudoku_Area, BUTTON_PRESS_MASK);
CR := Create(Get_Window (Sudoku_Area));
Event_Cb.Connect (Sudoku_Area, "draw",
                  Event_Cb.To_Marshaller 
(On_Area_Draw'Unrestricted_Access));
Event_Cb.Connect (Sudoku_Area, "button_press_event",
                  Event_Cb.To_Marshaller 
(On_Button_Press'Unrestricted_Access));

The problem stays the same as.

Just for extra information the code od On_Button_Press:

function On_Button_Press (Object : access Gtk_Drawing_Area_Record'Class; 
event : Gdk_Event) return boolean is
   pragma Unreferenced (Object);
begin
   ev := event.Button;  -- line where the breakpoint is invoked
   nb := ev.Button;
   if nb = 1 then
      x := ev.X;
      y := ev.Y;
   end if;
   return nb = 1;
end On_Button_Press;


"Dmitry A. Kazakov"  schreef in bericht 
news:qtjn56kj6yh4$.1iqlazgzyni86.dlg@40tude.net...

On Tue, 4 Feb 2014 07:46:51 +0100, ldries46 wrote:

> I do want to draw something at a certain point in a Drawing_Area. That 
> point
> should be derived from a mouse click.
> To do this I have created a handler "On Button_Press".

[...]

> Both program build faultless.
> I put a breakpoint inside the On_Button_Press function at a point where it
> should always be reached.
> Running the program and clicking within the drawn area that breakpoint is
> never reached and the program runs without reporting an error.
> I am using Gtk 3.4 and GPS.
> What do I do wrong?

By default the button-press-event and the button-release-event signals are
filtered out for a widget. See:

https://developer.gnome.org/gtk3/stable/GtkWidget.html#GtkWidget-button-press-event

You must enable their propagation in order to be able to handle them. Use
Set_Events for this purpose on the widget with the appropriate event mask.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de