OK, last update on this issue: the problem lies in the fact that the X server doesn't know anything about trading width for height, and so determining a (minimum) allocation to ask for the toplevel window is not a trivial thing to do for the layouting engine.
See this reply: https://mail.gnome.org/archives/gtk-devel-list/2013-June/msg00053.html and this bug: https://bugzilla.gnome.org/show_bug.cgi?id=681937#c12 for more info. Pietro Il giorno mar, 18/06/2013 alle 17.10 +0200, Pietro Battiston ha scritto: > I have found an explanation... in the official documentation. > > "The minimum height for the minimum width is normally used to set the > minimum size constraint on the toplevel (unless > gtk_window_set_geometry_hints() is explicitly used instead)." > > But the real answer to my problem is not in that sentence, but in its > non-obvious (to me) consequence: Gtk.Widget.do_get_preferred_width() > should _not_ return the minimal width the widget will ever be able to > cope with, but rather its width in some reasonable form factor, though > as compressed as possible. > > (still, I don't see the rational for this design choice, since the > layout algorithm will not be able to know the _real_ minimum width of my > widget) > > Pietro > > Il giorno lun, 17/06/2013 alle 20.20 +0200, Pietro Battiston ha scritto: > > Hello, > > > > I'm designing a widget. Its "do_get_request_mode(self)" returns > > Gtk.SizeRequestMode.HEIGHT_FOR_WIDTH. > > > > > > Now, in a testcase, the widget does the following: > > 1) do_get_preferred_width() is called: it returns 53 (minimum), 212 > > (natural) > > 2) do_get_preferred_height_for_width() is called with width 53: it > > returns 170, 170 > > 3) do_get_preferred_height_for_width() is called with width 212: it > > returns 51, 51 > > > > So far, so good: the widget has received all the calls I expected, and > > returned what I wanted it to. But now, what I would expect (at least in > > a test case in which no other widgets are reclaiming anything) would be > > that the widget is offered (212, 51). Instead, not only it is offered > > (212, 170), but the 170 is considered as minimum - I'm unable to resize > > the widget to something smaller. Now, I did declare 170 as a minimum... > > but only in the case in which the width is 53! > > > > To reproduce, you can do: > > git clone git://pietrobattiston.it/quack > > cd quack > > git checkout wrapbox_error > > cd plugins/tags > > python test_wrapbox.py > > > > to understand what I would like, just replace the "if nat:" at line 93 > > with "if True:", and rerun. > > > > Thank you in advance for any enlightenment, or pointer to a good > > discussion of such issues. > > > > Pietro > > > > _______________________________________________ > > pygtk mailing list pygtk@daa.com.au > > http://www.daa.com.au/mailman/listinfo/pygtk > > Read the PyGTK FAQ: http://faq.pygtk.org/ > > > _______________________________________________ > pygtk mailing list pygtk@daa.com.au > http://www.daa.com.au/mailman/listinfo/pygtk > Read the PyGTK FAQ: http://faq.pygtk.org/ _______________________________________________ pygtk mailing list pygtk@daa.com.au http://www.daa.com.au/mailman/listinfo/pygtk Read the PyGTK FAQ: http://faq.pygtk.org/
