It was a right cow to get working at all due to the tangled mess of
dependencies between different hierarchies (switching to hierarchies as
components helpt), but other that some vertical positioning (paragraphs
and descenders), it's working fairly well now (and fairly quick other
than I think I need to ensure the shaping cache is used).
This is for scroll boxes (the nesting of canvases is for the clipping
they provide). There are some issues with automatic layout, but this
gets things mostly working, in particular the management of the link
between hierarchies as a canvas is always the root of its hierarchy.
Much of the state handling was highly redundant (in particular, handling
entity and old_entity). This should make it easier to get dragable items
for window resizing.
Panels can be anchored to a widget in another hierarchy, allowing for
things like cascading menus. They can also be extended via referencing
them by name, allowing for subsystems to add items to an already panel
(eg, extending a menu).
The intent is to use them for menus, tooltips and anything else along
those lines, but windows was a good starting point (and puts a border
along the top of the window too).
By default, horizontal and vertical layouts expand to fill their parent
in their on-axis direction (horizontally for horizontal layouts), but
fit to their child views in their off-axis.
Flexible space views take advantage of auto-expansion, pushing sibling
views such that the grandparent view is filled on the parent view's
on-axis, and the parent view is filled by the space in the parent view's
off-axis. Flexible views currently have a background fill, allowing them
to provide background filling of the overall view with minimal overdraw
(ancestor views don't need to have any fill at all).
TextContent seems redundant at this stage since a text view is always
sized to its content, and PercentOfParent doesn't work yet. Pixels
definitely works and Null seems to work in that it does no sizing or
positioning. Vertical layout is supported but not yet tested, similar
for ChildrenSum, but I can have two buttons side by side.
