The first in many NodeView improvements. Up until now, nodes have been forcibly
auto-arranged, which has worked as a reasonable stop-gap just so that all the
nodes are visible during testing/development. However this does not make a good
user experience.
We move the auto-arrange code to a manual function that can be used when the
user or program deems it necessary, and also abstract the node positions so that
the view can ultimately determine the exact amount of spacing (useful for
changing DPIs) or orientation, so users can direct the flow whichever way they
want.
Rather than the cumbersome and small "node connectors" (introduced a while ago
when nodes had more than one output), this is a more streamlined system of
connecting nodes (hold Ctrl and drag to connect)
Previous iteration used some "magic code" that added clips automatically to the
timeline. This was functional but ultimately outside of the undo commands'
control meaning nodes could be infinitely added and abandoned. This makes the
add process part of the undo command which means it's all undoable as the user
would expect.
Old code assumes that a NodeParam's parent will always be a Node. The function
has been separated off and tweaked in the event that this is not the case.
Nodes were previously written to be "strongly typed" in that a parameter's
"type" enforced whether it could be connected to another. All code related
to that has now been removed since not only is it hard to maintain and
likely unnecessary, it's possible the nodes will work differently later on
anyway.