I've been working on a terminal emulator project called zTerm in my spare time, and wanted to share some lessons learned along the way.
The Stack
-
Terminal emulation: Built on top of
alacritty_terminal- no need to reinvent the wheel for VT parsing - UI Framework: GPUI, the same framework that powers the Zed editor, with GPU-accelerated rendering
- Component library: gpui-component from Longbridge
I chose GPUI because I was curious about what makes Zed's rendering so smooth. Wanted to see if I could achieve similar results.
Challenges I Faced
Cross-Platform PTY
The differences between Windows ConPTY and Unix PTY were bigger than expected. Signal handling and process lifecycle management took significant debugging time.
IME Support
Supporting Chinese/Japanese/Korean input methods was tricky. Cursor positioning, candidate window placement, and composition state handling all behave differently across platforms. GPUI's documentation is sparse here, so I ended up reading Zed's source code.
Rendering Performance
Initially, I was triggering a render on every PTY event. Running cat on a large file would freeze the terminal. Adding a 4ms batching interval to coalesce multiple events before rendering made a huge difference.
Current Status
Basic functionality works: multi-tab support, scroll history, mouse selection, and keyboard shortcuts. Split panes are in progress, and theming is planned.
The code is still rough around the edges. If you have experience with GPUI or terminal emulators, feedback and PRs are welcome.
GitHub: https://github.com/zerx-lab/zTerm
Built with Rust. No pre-built releases yet - you'll need to compile from source if you want to try it out.
Top comments (1)
GPUI is interesting, Zed's bet on it makes sense for their use case but I've been curious how it compares to egui for general desktop apps. I went with egui for a markdown editor project and the immediate-mode model took some getting used to, but the "no retained state in widgets" constraint actually simplified a lot of things.
How's the text rendering story with GPUI? That's where I hit the most friction with egui - getting proper font metrics and IME support right is surprisingly fiddly.