Re: Dragging a window

[lecas malecas <darkiiiiii gmail com>]

when would get_window() fail?

I'm calling it in on_motion_notify_event(), so there's always a
window, otherwise the event wouldn't trigger... at least that's what I
think.

2011/12/11 Adam Chyła <adam chyla tk>:
> Don't do that:
>
>> >
>> > get_window()->set_cursor(cursor);
>> >
>
> What about error checking?
>
> Glib::RefPtr<Gdk::Window> window = get_window();
>  if (window)
>    window->set_cursor(...);
>
>
> Dnia 2011-12-11, o godz. 04:50:25
> lecas malecas <darkiiiiii gmail com> napisał(a):
>
>> It does work... was running the code in the wrong place, sorry :)
>>
>>
>> On Sun, Dec 11, 2011 at 4:31 AM, lecas malecas <darkiiiiii gmail com>
>> wrote:
>> > Yep, that works. thanks!
>> >
>> > Just another doubt, to change the cursor of the mouse (the image).
>> >
>> >
>> > I think its something like this:
>> >
>> > const Glib::RefPtr< Gdk::Cursor > cursor =
>> > Gdk::Cursor::create(Gdk::HAND1);
>> >
>> > get_window()->set_cursor(cursor);
>> >
>> > but I'm getting a seg. fault in the last line :(
>> >
>> >
>> > On Sun, Dec 11, 2011 at 3:30 AM, Adam Chyła <adam chyla tk> wrote:
>> >>  Hi,
>> >> Take a look at that code
>> >>
>> >> // http://paste.org/42104
>> >> // GTKmm 2.4
>> >>
>> >> #include <gtkmm.h>
>> >>
>> >> using namespace Gtk;
>> >>
>> >> class window : public Window
>> >> {
>> >> public:
>> >>
>> >>    window()
>> >>    {
>> >>        set_title("Example");
>> >>        show_all_children();
>> >>
>> >>        add_events(Gdk::BUTTON_PRESS_MASK);
>> >>        add_events(Gdk::POINTER_MOTION_MASK);
>> >>    }
>> >>
>> >> private:
>> >>    int mouse_beg_x, mouse_beg_y;
>> >>    int win_pos_beg_x, win_pos_beg_y;
>> >>
>> >>    bool on_button_press_event(GdkEventButton* event)
>> >>    {
>> >>        mouse_beg_x = event->x_root;
>> >>        mouse_beg_y = event->y_root;
>> >>
>> >>        get_position(win_pos_beg_x, win_pos_beg_y);
>> >>
>> >>        return true;
>> >>    }
>> >>
>> >>    bool on_motion_notify_event(GdkEventMotion* event)
>> >>    {
>> >>        if (event->state & GDK_BUTTON1_MASK)
>> >>        {
>> >>            int x = win_pos_beg_x + (event->x_root - mouse_beg_x);
>> >>            int y = win_pos_beg_y + (event->y_root - mouse_beg_y);
>> >>
>> >>            move(x, y);
>> >>        }
>> >>        return true;
>> >>    }
>> >> };
>> >>
>> >> int main(int argc, char **argv)
>> >> {
>> >>    Gtk::Main kit(argc, argv);
>> >>
>> >>    window win;
>> >>    Gtk::Main::run(win);
>> >>
>> >>    return 0;
>> >> }
>> >>
>> >>
>> >> Good luck
>> >> Adam
>