This is only tangentially related but if you are looking for a 2d rendering api for Rust, peep femtovg https://github.com/femtovg/femtovg

Join the discord https://discord.gg/V69VdVu

Quite a few people have been using it to build their own GUI. Add some layout, windowing and event handling and you have yourself a GUI.

This demo UI (https://github.com/femtovg/femtovg/blob/master/assets/demo.p...) is the same one I've seen in the Pathfinder (https://github.com/servo/pathfinder) examples. Is it something common, like the tiger used to demo SVG libraries?