Hi again! This post was an early exploration into GPU rendering. The work continues as piet-gpu, and, while it's not yet a complete 2D renderer, there's good progress, and also an active open source community including people from the Gio UI project. I've not long ago implemented nested clipping (which can be generalized to blend modes) and have a half-finished blog post draft. I'm also working on this as my work as a researcher on the Google Fonts team. Feel free to ask questions in this thread - I probably won't follow up with everything, as the discussion is pretty sprawling.