The layouting was becoming too complex to maintain and to introduce
new features. Was even buggy, the fuzzer was constantly finding
bugs, which took hours to workaround.
Problem with the old layout engine is that there was a catch 22, between
Items driving the separators, and separators driving the anchors.
The new layout is much simpler, both in implementation and conceptually.
There's simply a recursive hierarchy of Item elements. An Item can either
have a QWidget to show, or be a ItemContainer, which contains Item children,
and so forth. Each ItemContainer is either vertical or horizontal. That's enough
to represent the "nested multi-splitter" concept which KDDW uses.
After each item insertion/deletion/resize, the separators are regenerated. They
are essentially dumb now.
TODO:
- Separators are drawn, but are not interactive yet
- There's 5 tests failing
- LayoutSaver scalling functionality
By default a dock widget can dock into any main window.
With affinities, we can now have a dock widget "belong" to a main window
and only be able to dock into it (or into other floating dock widgets
with the same affinity).
See DockWidgetBase::setAffinity() and MainWindowBase::setAffinity().
