How to make window resizable without having decorations? (gtkmm3 , X11)

Hamza_Algohary · July 11, 2022, 9:47pm

I’m creating a panel in gtk3 for X11. I managed to implement many functionalities needed in panel window. However, I don’t know how to make it resizable without having decorations.
I tried using gtk_window_begin_resize_drag() but it doesn’t work as expected. What’s the most straightforward way of doing that, or how can I use this function properly, please also explain what this function does specifically.

lb90 · July 11, 2022, 10:34pm

begin_resize_drag() is the right method to use. You should call it from a button-press event handler of your window.

#include <gtkmm.h>

class MyWindow
 : public Gtk::Window
{
public:
  MyWindow();

protected:
  bool on_button_press(GdkEventButton *button_event);
};

bool MyWindow::on_button_press(GdkEventButton *button_event)
{
  if (button_event->button == 1)
    get_window()->begin_resize_drag(
          Gdk::WINDOW_EDGE_SOUTH_EAST,
          button_event->button,
          button_event->x_root,
          button_event->y_root,
          button_event->time);

  return false; // propagate event further
}

MyWindow::MyWindow()
 : Gtk::Window(Gtk::WINDOW_TOPLEVEL)
{
  /* constructor */

  add_events(Gdk::POINTER_MOTION_MASK |
             Gdk::BUTTON_PRESS_MASK |
             Gdk::BUTTON_RELEASE_MASK);
  signal_button_press_event().connect(sigc::mem_fun(*this, MyWindow::on_button_press));
}

int main(int argc, char **argv)
{
  auto app =
    Gtk::Application::create(argc, argv,
      "org.gtkmm.examples.base");

  MyWindow window;
  window.set_default_size(200, 200);

  return app->run(window);
}