This function will be useful in other places, such as determining the
widgets that must receive crossing events after pointer picking points
to another widget.
gtk_widget_set_parent (via gtk_widget_reposition_after) will queue a
resize on the parent widget automatically when adding a child widget, so
unparent should do the same
If the widget isn't drawable anyway, just return;
If the widget needs an allocate, print a warning, since it indicates a
problem in the widget workflow (e.g. forgot to size_allocate a child
widget).
This maches the previous checks in gtk_widget_draw (with the same
problems).
Since the later gtk_style_context_add_class doesn't care about the order
of the style classes, we can as well just prepend style classes to the
list and avoid the squared behavior when appending to a linked list.
Since margin-left and margin-right are gone, we don't have to care
about the difference between them and start/end anymore and we can just
save start as left and end as right.
When a widget is created, its default scale is the scale of the
primary screen (for instance 2). But once parented to another widget
its scale factor should be the one of its parent (if parented to a
widget on a screen at scale factor 1, it should be 1).
The problem is that we don't emit the notify::scale-factor signal when
reparenting happens.
https://bugzilla.gnome.org/show_bug.cgi?id=776821
gtk_snapshot_pop() => removed
gtk_snapshot_pop_and_append() => gtk_snapshot_pop()
So now there is no way to get a rendernode out of the snapshotting API
until you gtk_snapshot_finish().
We already take ints when setting the translation, so it can't
currently take any other values. Additionally, I was seeing large
costs in int -> double -> int for the rects in
gtk_snapshot_clips_rect(), as all callers really are ints (widget
allocations) and the clip region is int-based.
This change completely cleared a 2% rectangle_init_from_graphene from
the profile and is likely to have nice performance effects elsewhere
too.
So we can set the css name of a widget to something that's not related
to the class name. If the css-name property is set to NULL, we will
still fall back to the one set using gtk_widget_class_set_css_name which
is alwasys non-NULL since GtkWidget itself sets it to "widget".
