Architecture

This document describes how the crates that make up egui are all connected.

Also see CONTRIBUTING.md for what to do before opening a PR.

Crate overview

The crates in this repository are: egui, emath, epaint, epaint_default_fonts, egui_extras, egui-winit, egui_glow, egui-wgpu, egui_demo_lib, egui_demo_app.

egui: The main GUI library.

Example code: if ui.button("Click me").clicked() { … } This is the crate where the bulk of the code is at. egui depends only on emath and epaint.

emath: minimal 2D math library

Examples: Vec2, Pos2, Rect, lerp, remap

epaint

2d shapes and text that can be turned into textured triangles.

Example: Shape::Circle { center, radius, fill, stroke }

Depends on emath. Also depends on epaint_default_fonts when the default_fonts feature is enabled.

epaint_default_fonts

Embedded fonts (using include_bytes!()) for use by epaint in selecting defaults.

Since the font files themselves are licensed differently from the epaint source code, this simplifies licenses for callers who disable the default fonts.

egui_extras

This adds additional features on top of egui.

egui-winit

This crates provides bindings between egui and winit.

The library translates winit events to egui, handled copy/paste, updates the cursor, open links clicked in egui, etc.

egui_glow

Puts an egui app inside a native window on your laptop. Paints the triangles that egui outputs using glow.

egui-wgpu

Paints the triangles that egui outputs using wgpu.

eframe

eframe is the official egui framework, built so you can compile the same app for either web or native.

The demo that you can see at https://www.egui.rs is using eframe to host the egui. The demo code is found in:

egui_demo_lib

Depends on egui. This contains a bunch of uses of egui and looks like the ui code you would write for an egui app.

egui_demo_app

Thin wrapper around egui_demo_lib so we can compile it to a web site or a native app executable. Depends on egui_demo_lib + eframe.

egui_kittest

A test harness for egui based on kittest and AccessKit.

Other integrations

There are also many great integrations for game engines such as bevy and miniquad which you can find at https://github.com/emilk/egui#integrations.