4d6a3c7e11
Provide a way to prevent GPUI from creating AccessKit adapters, and enable this in Zed. This will allow us to test AccessKit support in Zed without rolling it out more broadly, while we gain confidence in the implementation in GPUI. I've also added a log statement ## Motivation (i.e. a mini post-mortem about the #56065 panics) Merging #56065 caused some nasty panics in nightly. This was caused by a bug in the logic for selecting a focus node for a `TreeUpdate`. AccessKit panics when an invalid `TreeUpdate` is provided. My assumption was that, since Zed uses no a11y APIs, and also that essentially 0 zed users would have AT apps running, that merging this PR would have no effect on the behaviour of Zed itself. However, two issues combined to cause the panics: - It seems like many people (everyone?) on mac gets the activation callback called by accesskit_macos. A quick search suggests this might be due to password managers searching for password fields, but not sure how true that is. - The bug in question related to *forgetting to check* whether a node used a11y APIs, so we *were* pushing non-empty `TreeUpdate`s As a (probably temporary) defensive measure, I added a function to try to detect the bad cases and fix them. But it would be lovely if this could live in AccessKit itself, since it would mean we wouldn't have to do the check twice (once in GPUI, once in AccessKit). This would also help prevent drift when updating accesskit versions if new invariants are added. We also cannot protect against this with `catch_unwind`, since we use `panic=abort`. So our only option unfortunately is to temporarily disable AccessKit until we know our implementation is stable. Release Notes: - N/A or Added/Fixed/Improved ... |
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Welcome to GPUI!
GPUI is a hybrid immediate and retained mode, GPU accelerated, UI framework for Rust, designed to support a wide variety of applications.
Getting Started
GPUI is still in active development as we work on the Zed code editor, and is still pre-1.0. There will often be breaking changes between versions. You'll also need to use the latest version of stable Rust and be on macOS or Linux. Add the following to your Cargo.toml:
gpui = { version = "*" }
Everything in GPUI starts with an Application. You can create one with Application::new(), and kick off your application by passing a callback to Application::run(). Inside this callback, you can create a new window with App::open_window(), and register your first root view. See gpui.rs for a complete example.
Dependencies
GPUI has various system dependencies that it needs in order to work.
macOS
On macOS, GPUI uses Metal for rendering. In order to use Metal, you need to do the following:
- Install Xcode from the macOS App Store, or from the Apple Developer website. Note this requires a developer account.
Ensure you launch Xcode after installing, and install the macOS components, which is the default option.
-
Install Xcode command line tools
xcode-select --install -
Ensure that the Xcode command line tools are using your newly installed copy of Xcode:
sudo xcode-select --switch /Applications/Xcode.app/Contents/Developer
The Big Picture
GPUI offers three different registers depending on your needs:
-
State management and communication with
Entity's. Whenever you need to store application state that communicates between different parts of your application, you'll want to use GPUI's entities. Entities are owned by GPUI and are only accessible through an owned smart pointer similar to anRc. See theapp::contextmodule for more information. -
High level, declarative UI with views. All UI in GPUI starts with a view. A view is simply an
Entitythat can be rendered, by implementing theRendertrait. At the start of each frame, GPUI will call this render method on the root view of a given window. Views build a tree ofelements, lay them out and style them with a tailwind-style API, and then give them to GPUI to turn into pixels. See thedivelement for an all purpose swiss-army knife of rendering. -
Low level, imperative UI with Elements. Elements are the building blocks of UI in GPUI, and they provide a nice wrapper around an imperative API that provides as much flexibility and control as you need. Elements have total control over how they and their child elements are rendered and can be used for making efficient views into large lists, implement custom layouting for a code editor, and anything else you can think of. See the
elementmodule for more information.
Each of these registers has one or more corresponding contexts that can be accessed from all GPUI services. This context is your main interface to GPUI, and is used extensively throughout the framework.
Other Resources
In addition to the systems above, GPUI provides a range of smaller services that are useful for building complex applications:
-
Actions are user-defined structs that are used for converting keystrokes into logical operations in your UI. Use this for implementing keyboard shortcuts, such as cmd-q. See the
actionmodule for more information. -
Platform services, such as
quit the apporopen a URLare available as methods on theapp::App. -
An async executor that is integrated with the platform's event loop. See the
executormodule for more information., -
The
[gpui::test]macro provides a convenient way to write tests for your GPUI applications. Tests also have their own kind of context, aTestAppContextwhich provides ways of simulating common platform input. Seeapp::test_contextandtestmodules for more details.
Currently, the best way to learn about these APIs is to read the Zed source code or drop a question in the Zed Discord. We're working on improving the documentation, creating more examples, and will be publishing more guides to GPUI on our blog.