If multiple nested widgets have drag sources on them, both using bubble
phase, we need to reliably pick the inner one. Both of them will try to
start dragging, and we need to make sure there are no situations where the
outer widget starts drag earlier and cancels the inner one.
Currently, this can easily happen via integer rounding: start and current
coordinates passed into gtk_drag_check_threshold() are initially doubles
(other than in GtkNotebook and GtkIconView), and are casted to ints. Then
those rounded values are used to calculate deltas to compare to the drag
threshold, losing quite a lot of precision along the way, and often
resulting in the outer widget getting larger deltas.
To avoid it, just don't round it. Introduce a variant of the function that
operates on doubles: gtk_drag_check_threshold_double() and use it instead
of the original everywhere.
Ensure that the column resize cursor stays in place
for the duration of the resize drag. This is a bit
annoying, since the implicit grab can end up on the
header of a different column from the one we are
resizing, so just set the cursor on all column headers.
Make it so that for overlapping resize rectangles (with
very narrow columns), we prefer the narrow column, so you
can regrow a column after shrinking it all the way.
Related: #3274
Ensure that we place the resize rectangle at the visible
right edge of the column, not where the allocation ends
(we clip the header drawing, after all).
Related: #3274
Use the TREE_GRID, ROW, COLUMN_HEADER and GRID_CELL roles
for the various widgets involved in a GtkColumnView. To
enable this, we subclass GtkListView for the internal
list in the column view.
Removed sentence that claimed the view will wrap the model in a
GtkSingleSelection, as it's no longer true. Fixed the code example in
GtkListView for the same reason. Fixed a small typo in GtkDropDown docs.
Now that both arguments to the _new_with_factory() constructors
are nullable, there's no good reason to keep a separate _new()
around. Just make gtk_list_view_new() and gtk_grid_view_new()
take both a model and a factory.
Change the apis in GtkListView, GtkColumnView and
GtkGridView to be explicitly about GtkSelectionModel,
to make it obvious that the widgets handle selection.
Update all users.
Make both gtk_list_view_new and gtk_list_view_new_with_factory
take a model as first argument, and make all arguments
allow-none and transfer full.
Update all callers.
Use a drop motion controller to autoscroll horizontally
while a drag operation is hovering over the list. The
vertical scrolling is handled by the listview.
Tell reordered columns to reorder their cells to
the new position. This is necessary to get things
like separators right. The visible symptom of this
problem was the lack of the right border when the
last column is reorder to another position, since
the title widget was still the last in its container,
so :last-child applied.
The new names are
GtkListView - listview row
GtkGridView - gridview child
GtkColumView - columnview header
columnview listview row
Adwaita css has been updated to preserve
existing styles.
Fixes: #2818
Rename the show-separators property to show-row-separators,
and add a matching show-column-separators property. It is
implemented by setting the .column-separators style class
on the column view.
Autoscroll when the pointer gets close to the
edge during column resizing or reordering. This
is similar to what the treeview does, but it is
implemented using a tick callback, and has
variable speed.
Allow rearranging columns by dragging, in the same
way the treeview does.
We add the "dnd" style class to the header while
it is dragged, and we move the header of the dragged
column to the end of its parents children, so that
it gets drawn on top.
The listview inside always thinks it gets its full size,
and updates its horizontal adjustment accordingly.
So keep our own adjustment, and update it when allocating.
Tweak the behavior slightly. We don't show
a scrollbar as long as we have at least
min-size available, but we still give the
entire size to the child, up to nat-size.
This matches how viewports handle scroll-minimum.
