GPU acceleration would depend on the Xi frontend. I know that xi-win (https://github.com/google/xi-win) uses Direct2D and DirectComposition. DirectWrite is on the CPU, though, AFAIK. It would be cool to hook it up to pathfinder for a full-stack GPU editor, but I'm not sure it would make a huge difference vs CPU+glyph caching.
> DirectWrite is on the CPU, though, AFAIK.
DirectWrite rasterises glyphs on the GPU when used with Direct2D. GPU path rasterisation was Direct2D's killer feature when it was initially released with Windows 7.
For what it's worth, there's also a terminal emulator with similar goals (GPU acceleration included): https://github.com/jwilm/alacritty
(¶) Then again, drawing the text is rarely the bottleneck of a text editor (as the sibling post's author correctly points out). It's usually the data structure to represent the text internally and syntax highlighting that have the greatest influence. (Advanced IDE features like syntax checks, linter and indexing aside.)