95842c7987
## Problem statement I want to add keyboard navigation support to SSH modal. Doing so is possible in current landscape, but not particularly ergonomic; `gpui::ScrollHandle` has `scroll_to_item` API that takes an index of the item you want to scroll to. The problem is, however, that it only works with it's immediate children - thus in order to support scrolling via keyboard you have to bend your UI to have a particular layout. Even when your list of items is perfectly flat, having decorations inbetween items is problematic as they are also children of the list, which means that you either have to maintain the mapping to devise a correct index of an item that you want to scroll to, or you have to make the decoration a part of the list item itself, which might render the scrolling imprecise (you might e.g. not want to scroll to a header, but to a button beneath it). ## The solution This PR adds `ScrollAnchor`, a new kind of handle to the gpui. It has a similar role to that of a ScrollHandle, but instead of tracking how far along an item has been scrolled, it tracks position of an element relative to the parent to which a given scroll handle belongs. In short, it allows us to persist the position of an element in a list of items and scroll to it even if it's not an immediate children of a container whose scroll position is tracked via an associated scroll handle. Additionally this PR adds a new kind of the container to the UI crate that serves as a convenience wrapper for using ScrollAnchors. This container provides handlers for `menu::SelectNext` and `menu::SelectPrev` and figures out which item should be focused next. Release Notes: - Improve keyboard navigation in ssh modal |
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| README.md | ||
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 isn't yet on crates.io. 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 = { git = "https://github.com/zed-industries/zed" }
Everything in GPUI starts with an App. You can create one with App::new(), and kick off your application by passing a callback to App::run(). Inside this callback, you can create a new window with AppContext::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 Models. Whenever you need to store application state that communicates between different parts of your application, you'll want to use GPUI's models. Models are owned by GPUI and are only accessible through an owned smart pointer similar to an
Rc. See theapp::model_contextmodule for more information. -
High level, declarative UI with Views. All UI in GPUI starts with a View. A view is simply a model that can be rendered, via the
Rendertrait. 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::AppContext. -
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, ask us about it at a fireside hack, 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.