To address your comments:
- Maybe you didn't notice, but the API of the model layer depends only on very basic Java classes, and not on classes of java.awt.geom package I did nit notice that as a design coice. I saw that you have used instances of Line2D from java.awt.geom so did not see a reason ...

I get that, but my thought is to actually make an underlying change to the 2d system. Basically to make the program behave more like a modern CAD system with a fully constraint based design. This is a step in that direction. It's not just changing float[] to vector2D for convenience, it is changing ...

Also, I just posted a second patch with save/load completed for vectors. Still need to make it convert the old saved files.

That's a valid concern. Is the API what plugins use? Do API developers access these finctions directly, or does the API act as a layer? I wrote toFloatArray() / fromFloatArray functions in the Vector2D class that convert betweenn the two as there are same java built-in libraries that use float ...

Patch submitted - ticket #1090

No functionality lost as far as I am aware. I am still working on making the new version save/load and will need to be able to update older saved files to the new version. I also didn't completely replace all of the float arrays in the entire codebase. It was a lot of ...

I'm not sure where is the best place to submit a patch. I have been working on a modification that I think will be useful. This program would benefit greatly from a constraint solver. This would allow for things like locking walls to a certain length/angle or having dimensions that are attached to ...