resizable viewport

[nornagon-openai]

Proof of concept for a resizable viewport.

The general approach here is to duplicate the Terminal struct from ratatui, but with our own logic. This is a "light fork" in that we are still using all the base ratatui functions (Buffer, Widget and so on), but we're doing our own bookkeeping at the top level to determine where to draw everything.

This approach could use improvement—e.g, when the window is resized to a smaller size, if the UI wraps, we don't correctly clear out the artifacts from wrapping. This is possible with a little work (i.e. tracking what parts of our UI would have been wrapped), but this behavior is at least at par with the existing behavior.

Screen.Recording.2025-07-29.at.4.03.50.PM.mov

cc @joshka who might have Thoughts™

[joshka]

Just a quick reminder. Please follow the MIT license conditions. The easiest way is to copy the license into your NOTICES file. I encourage liberal copying and modification of source code like this, with appropriate attribution being the only real requirement.

[nornagon-openai]

pulled it into this file directly, i'm not sure exactly how our distribution works and what notices are shipped with the binaries but would be happy to include this notice there too.

[joshka]

This sounds ok to me. I don't recall exactly whether any runtime license notice requirement is required. When I last researched this I was unable to find any definitive guidance on what the right approach is. I suspect every company at some point has this come up and lawyers work out an interpretation that works for them™ ;)

I've been meaning to sometime broach with the rest of the team making Ratatui dual licensed as Apache 2, and doing the right thing to include the standard license headers like this in each file, which would make it a bit easier to do things like this.

[bolinfest]

Very small questions, but please address the points raised by @joshka before submitting!