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ARCHITECTURE.md

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+# Arcitecture
+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, egui, epi, egui_web, egui_glium, 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`, [`rusttype`](https://crates.io/crates/rusttype), [`atomic_refcell`](https://crates.io/crates/atomic_refcell), [`ahash`](https://crates.io/crates/ahash).
+
+### `epi`
+Depends only on `egui`.
+Adds a thin application level wrapper around `egui` for hosting an `egui` app inside of `eframe`.
+
+### `egui_web`
+Puts an egui app inside the web browser by compiling to WASM and binding to the web browser with [`js-sys`](https://crates.io/crates/js-sys) and [`wasm-bindgen`](https://crates.io/crates/wasm-bindgen). Paints the triangles that egui outputs using WebGL.
+
+### `egui_glium`
+Puts an egui app inside a native window on your laptop. Paints the triangles that egui outputs using [glium](https://github.com/glium/glium).
+
+### `eframe`
+A wrapper around `egui_web` + `egui_glium`, so you can compile the same app for either web or native.
+
+The demo that you can see at <https://emilk.github.io/egui/index.html> is using `eframe` to host the `egui`. The demo code is found in:
+
+### `egui_demo_lib`
+Depends on `egui` + `epi`.
+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`.
+
+### 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>.