This is a somewhat large commit that:
- Adds GtkColumnViewSorter
This is a special-purpose, private sorter implementation which sorts
according to multiple sorters, allowing each individual sorter to be
inverted. This will be used with clickable column view headers.
- Adds a read-only GtkColumnView::sorter property
The GtkColumnView creates a GtkColumnViewSorter at startup that it uses
for this property.
- Adds a writable GtkColumnViewColumn::sorter property
This allows defining per-column sorters. Whenever an application sets a
sorter for a column, the header becomes clickable and whenever
a header is clicked, that column's sorter is prepended to the list of
sorters, unless it is already the first sorter, in which case we invert
its order. No column can be in the list more than once.
Add a mode to GtkListItemWidget that activates on
single click and selects on hover. Make
GtkListItemManager set this on its items
when its own 'property' of the same name is set.
The port is kind of evil, in that it stores either a PangoFontFamily or a
PangoFontFace in the list, depending on if the fontchooser is configured
to select fonts or faces.
It also does not cache the font description anymore, so more calls to
pango_font_describe() may happen.
If both of these issues turn out problematic, the fontchooser would need
to resurrect GtkDelayedFontDescription again and put objects of that
type through the model.
These changes depend on Pango 1.46's introduction of listmodels and
various new getters, so the dependency has been upgraded.
This uses a custom GtkColumnViewTitle widget. So far that widget is
pretty boring, but that will change once we added
resizing, reordering, dnd, sorting, hiding/showing of columns or
whatever UIs we want.
The ColumnView now allocates column widths first and then the individual
rows use the new layout manager which looks at the column allocations to
allocate their children.
It's a GtkListItemWidget subclass that tracks the column it belongs to
and allows the column to track it.
We also use this subclass to implement sizing support so columns share
the same size and get resized in sync.
It's private, no APIs, we don't talk about it. But we will start using
it very soon, so we can do size request caching in columns and avoid
sizegroups...
We only create them in root/unroot (they should be created in
appear/disappear, but that vfunc doesn't exist yet), that way we can
avoid expensive work while the widget isn't used for anything.
