Finn Evers
ded6467604
Closes https://github.com/zed-industries/zed/issues/37621 Improves https://github.com/zed-industries/zed/issues/24623 Adding scrollbars withing Zed's UI currently is rather cumbersome, as it requires the copying of a lot of code in order for these to work. Wiring up settings for scrollbar visibilty always has to be done at the call site and the state has to be saved and maintained by the caller as well. Similarly, reserving space has to also be handled by the caller. This PR changes the way scrollbars work in Zed fundamentally by making use of the new `use_keyed_state` APIs: Instead of saving the state at the call site, the window now keeps track of the state corresponding to scrollbars. This enables us to add scrollbars with e.g. one simple call on divs: ```rust div() .vertical_scrollbar(window, cx) ``` will add a scrollbar to the corresponding container. There are some more improvements regarding tracking of scrollbar visibility settings (which is now handled by a trait for each setting that supports this) as well as reserving space. Additionally, all needed stuff for layouting, catching events and reserving space is also now managed by the scrollbar component instead. This drastically reduces the amount of event listeners and makes layouting of two scrollbars easier. Furthermore, this paves the way for more improvements to scrollbars, such as graceful auto-hide. Only downsight here is that we lose some customizability in a few areas. However, once this lands, we gain the ability to quickly follow these up without breaking stuff elsewhere. This also already fixes a few bugs: - Scrollbars no longer flicker on first render. - Auto-hide now properly works for all scrollbars. - If the content size changes, the scrollbar is updated on the same frame. Both of these happened because we were computing the scrollbar sizes too early, causing us to use the sizes from the previous frame or unitialized sizes. - The project panel no longer jumps if scrolled all the way to the bottom and the scrollbar actually auto-hides. Still TODO: - [x] Fix scrolling in the debugger memory view - [x] Clean up some more in the scrollbar component and reduce clones there - [x] Ensure we don't over-notify the entity the scrollbar is rendered within - [x] Make sure auto-hide properly works for all cases - [x] Check whether we want to implement the scrollbar trait for `UniformList`s as well - ~~ [ ] Use for uniformlist where possible~~ Postponed - [x] Improve layout for cases where we render both scrollbars. Release Notes: - N/A
Design notes:
This crate is split into two conceptual halves:
- The terminal.rs file and the src/mappings/ folder, these contain the code for interacting with Alacritty and maintaining the pty event loop. Some behavior in this file is constrained by terminal protocols and standards. The Zed init function is also placed here.
- Everything else. These other files integrate the
Terminalstruct created in terminal.rs into the rest of GPUI. The main entry point for GPUI is the terminal_view.rs file and the modal.rs file.
ttys are created externally, and so can fail in unexpected ways. However, GPUI currently does not have an API for models than can fail to instantiate. TerminalBuilder solves this by using Rust's type system to split tty instantiation into a 2 step process: first attempt to create the file handles with TerminalBuilder::new(), check the result, then call TerminalBuilder::subscribe(cx) from within a model context.
The TerminalView struct abstracts over failed and successful terminals, passing focus through to the associated view and allowing clients to build a terminal without worrying about errors.
#Input
There are currently many distinct paths for getting keystrokes to the terminal:
-
Terminal specific characters and bindings. Things like ctrl-a mapping to ASCII control character 1, ANSI escape codes associated with the function keys, etc. These are caught with a raw key-down handler in the element and are processed immediately. This is done with the
try_keystroke()method on Terminal -
GPU Action handlers. GPUI clobbers a few vital keys by adding bindings to them in the global context. These keys are synthesized and then dispatched through the same
try_keystroke()API as the above mappings -
IME text. When the special character mappings fail, we pass the keystroke back to GPUI to hand it to the IME system. This comes back to us in the
View::replace_text_in_range()method, and we then send that to the terminal directly, bypassingtry_keystroke(). -
Pasted text has a separate pathway.
Generally, there's a distinction between 'keystrokes that need to be mapped' and 'strings which need to be written'. I've attempted to unify these under the '.try_keystroke()' API and the .input() API (which try_keystroke uses) so we have consistent input handling across the terminal