High-DPI screen issues

[kdickerson]

Capturing issue reported via email from Viktor Engelmann.

Automaton sizing/layout is captured in pixels which results in issues for high-DPI displays. Need a more display-agnostic approach to storing/restoring layouts and determining sizing.

Unfortunately, I don't have any high-DPI displays to test and debug the issue.

[kdickerson]

Something that would help would be to translate state coordinates to be relative to the start state on serialization, then translate them back to parent-element left/top on display. This would at least make the serialized descriptions more predictable.

[kdickerson]

I played with storing start-state relative coordinates when serializing, but that runs in to issues where states can be rendered at positions less than 0 when loading on a different screen, which means you can't access them at all.

I played with storing locations as a percentage of the container, but the container can scroll, so on deserialization the graph would shrink in to the available space. If I also captured a container size the calculated result would be equivalent to storing the absolute positions that I already use.

For now I'm not doing anything to address. I need a workable solution.