Out of curiosity, what's the use for such library? If you are on a desktop surely there is a better native library to draw shapes, no?
At Soundslice, we have a custom sheet-music-rendering graphics library in frontend JavaScript/Canvas. We also need to generate vector PDFs serverside — so we use a node library that speaks the HTML Canvas API and can generate PDFs. This way the result is exactly the same as the rendered sheet music in the web browser. Nice! The upshot is: this kind of library allows for code reuse in non-browser contexts.
When you mentioned Soundslice I recognized your name :) Your recording of Django's Tiger is what got me into Jazz. Small world!