This change simplifies the parameter list for these functions
and reduces the chance of typos mixing up array indices.
Reviewed By: campbellbarton
Ref D12950
Tree-view items can now easily define their own context menu. This works
by overriding the `ui::AbstractTreeViewItem::build_context_menu()`
function. See the documentation:
https://wiki.blender.org/wiki/Source/Interface/Views#Context_Menus
Consistently with the Outliner and File Browser, the right-clicked item
also gets activated. This makes sure the correct context is set for the
operators and makes it clear to the user which item is operated on.
An operator to rename the active item is also added, which is something
you'd typically want to put in the context menu as well.
Now the icons to add or delete catalogs are only shown when mouse hovering a
catalog item in the tree. This is convenient for quick creation of catalogs,
and doesn't require activating a catalog to edit it first.
Determining if a tree item is hovered isn't trivial actually. The UI tree-view
code has to find the matching tree-row button in the previous layout to do so,
since the new layout isn't calculated yet.
Adds an easy way to add drop support for tree-view rows.
Most of the work is handled by the tree-view UI code. The tree items can
simply override a few functions (`can_drop()`, `on_drop()`,
`drop_tooltip()`) to implement their custom drop behavior.
While dragging over a tree-view item that can be dropped into/onto, the
item can show a custom and dynamic tooltip explaining what's gonna
happen on drop.
This isn't used yet, but will soon be for asset catalogs.
See documentation here:
https://wiki.blender.org/wiki/Source/Interface/Views#Further_Customizations
This follows three main targets:
* Make creation of new tree UIs easy.
* Groundwork to generalize tree UIs (so e.g. Outliner, animation
channels, asset catalogs and spreadsheet data-sets don't have to
re-implement basic tree UI code) or even other data-view UIs.
* Better separate data and UI state. E.g. with this, tree-item selection
or the open/collapsed state can be stored on the UI level, rather than
in data. (Asset Catalogs need this, storing UI state info in them is
not an option.)
In addition, the design should be well testable and could even be
exposed to Python.
Note that things will likely change in master still. E.g. the actually
resulting UI isn't very nice visually yet.
The design is documented here:
https://wiki.blender.org/wiki/Source/Interface/Views
Differential Revision: https://developer.blender.org/D12573
