GTK detecting window resize from the user

Question

In GTK (or pygtk or gtkmm...)

How can I detect that an application window has been manually resized by the user, as is typically done by dragging th

Answer 1

You may be able to throw something together by using gdk_window_get_root_origin to get the top left corner of the window and gdk_window_get_geometry to get the width and height. Then you could hook a callback into the GDK_BUTTON_PRESS_MASK and check to see if the button press occurs near/on one of the edges of the window.

Of course, this seems quite hackish and it really bothers me that I couldn't find some simple way in the documentation for GdkWindow to do this. There is a gdk_window_begin_resize_drag function which really makes me think there's a cleaner way to do this, but I didn't see anything more obvious than my answer.

Answer 2

In PyGTK, I've always watched for the expose_event for a window resize, then use the get_allocation method to get the new size.

Answer 3

I managed to pull this off by watching for size_allocate and size_request signals on the GtkWindow. If size_request ever got smaller, I called resize(1,1). If size_allocate was ever bigger than expected, I turned the system off.

One thing I made sure to handle was size_request returning big, then small, and having size_allocate be big and then small. I don't know if this is possible, but I fixed it by making sure to only decrease the expected values for size_allocate when I got a smaller size_allocate, not when I got a smaller size_request.

Make sure that your size_request handler comes after the base class' handler so that you get the right values. I did this by overriding the method and then calling the base class method first.

I've tried this in both 1 and 2 dimensions and it seems to work either way.

Answer 4

In my case I was trying to distinguish between a user resizing a Gtk.Paned from the user resizing the whole window. Both emitted the notify::position signal.

My solution was, since I can't know if the user is resizing the window from the widget, reverse what I wanted to know. Record if the user has re-positioned the widget and ignore updates if the user didn't initiate them on my widget.

That is to say, instead of testing "if window being resized" I recorded the button-press-event and button-release-event's locally so I could instead test "if widget being re-positioned"

from gi.repository import Gtk

class MyPaned(Gtk.Paned):
    _user_activated = False

    def on_position(self, _, gparamspec):
        if self._user_activated:
            # widget touched

        else:
            # window resized (probably)

    def on_button_press(self, *_):
        self._user_activated = True

    def on_button_release(self, *_):
        self._user_activated = False


    dev __init__(self, *args):
        super(MyPaned, self).__init__(*args)
        self.connect('notify::position', self.on_position)
        self.connect('button-press-event', self.on_button_press)
        self.connect('button-release-event', self.on_button_release)

Effectively by recorded when the user started and ended interacting with my widget directly, I could assume the rest of the time was due to the window being resized. (Until I find more cases)

Answer 5

Have you tried connecting to the GDK_CONFIGURE event?

Check out this example under the "Moving window" section. The example shows a callback doing something when the window is moved, but the configure event is a catch-all for moving, resizing and stack order events.