egui/crates/eframe
Liam Rosenfeld df9cd21248
Conditionally propagate web events using a filter in WebOptions (#5056)
Currently egui will prevent all web events from propagating. This causes
issues in contexts where you are using egui in a larger web context that
wants to receive events that egui does not directly respond to. For
example, currently using egui in a VSCode extension will block all app
hotkeys, such as saving and opening the panel.

This adds a closure to `WebOptions` that takes in a reference to the
egui event that is generated from a web event and returns if the
corresponding web event should be propagated or not. The default for it
is to always return false.

Alternatives I considered were:
1. Having the propagation filter be a property of the focus in memory.
That way it could be configured by the view currently selected. I opted
away from that because I wanted to avoid lowering eframe implementation
specific stuff into egui.
2. Having events contain a `web_propagate` flag that could be set when
handling them. However, that would not be compatible with the current
system of egui events being handled outside of the web event handler.

I just recently started using egui so I am not sure how idiomatic my
approach here is. I would be happy to switch this over to a different
architecture if there are suggestions.

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2024-09-05 08:48:13 +02:00
..
data Set a default icon for all eframe apps: a white `e` on black background (#2996) 2023-05-17 16:23:32 +02:00
src Conditionally propagate web events using a filter in WebOptions (#5056) 2024-09-05 08:48:13 +02:00
CHANGELOG.md Release 0.28.1 - Tooltip tweaks 2024-07-05 12:09:21 +02:00
Cargo.toml Remove the `directories` dependency (#4904) 2024-09-01 10:47:28 +02:00
README.md Remove the need for setting `web_sys_unstable_apis` (#5000) 2024-08-26 16:31:38 +02:00

README.md

eframe: the egui framework

Latest version Documentation MIT Apache

eframe is the official framework library for writing apps using egui. The app can be compiled both to run natively (for Linux, Mac, Windows, and Android) or as a web app (using Wasm).

To get started, see the examples. To learn how to set up eframe for web and native, go to https://github.com/emilk/eframe_template/ and follow the instructions there!

There is also a tutorial video at https://www.youtube.com/watch?v=NtUkr_z7l84.

For how to use egui, see the egui docs.


eframe uses egui_glow for rendering, and on native it uses egui-winit.

To use on Linux, first run:

sudo apt-get install libxcb-render0-dev libxcb-shape0-dev libxcb-xfixes0-dev libxkbcommon-dev libssl-dev

You need to either use edition = "2021", or set resolver = "2" in the [workspace] section of your to-level Cargo.toml. See this link for more info.

You can opt-in to the using egui_wgpu for rendering by enabling the wgpu feature and setting NativeOptions::renderer to Renderer::Wgpu.

Alternatives

eframe is not the only way to write an app using egui! You can also try egui-miniquad, bevy_egui, egui_sdl2_gl, and others.

You can also use egui_glow and winit to build your own app as demonstrated in https://github.com/emilk/egui/blob/master/crates/egui_glow/examples/pure_glow.rs.

Limitations when running egui on the web

eframe uses WebGL (via glow) and Wasm, and almost nothing else from the web tech stack. This has some benefits, but also produces some challenges and serious downsides.

  • Rendering: Getting pixel-perfect rendering right on the web is very difficult.
  • Search: you cannot search an egui web page like you would a normal web page.
  • Bringing up an on-screen keyboard on mobile: there is no JS function to do this, so eframe fakes it by adding some invisible DOM elements. It doesn't always work.
  • Mobile text editing is not as good as for a normal web app.
  • No integration with browser settings for colors and fonts.
  • Accessibility: There is an experimental screen reader for eframe, but it has to be enabled explicitly. There is no JS function to ask "Does the user want a screen reader?" (and there should probably not be such a function, due to user tracking/integrity concerns). egui supports AccessKit, but as of early 2024, AccessKit lacks a Web backend.

In many ways, eframe is trying to make the browser do something it wasn't designed to do (though there are many things browser vendors could do to improve how well libraries like egui work).

The suggested use for eframe are for web apps where performance and responsiveness are more important than accessibility and mobile text editing.

Companion crates

Not all rust crates work when compiled to Wasm, but here are some useful crates have been designed to work well both natively and as Wasm:

Name

The frame in eframe stands both for the frame in which your egui app resides and also for "framework" (eframe is a framework, egui is a library).