egui Custom Widgets: impl Widget for Reusable Components | Rust GUI Ep 25

Build a reusable toggle switch widget by implementing the egui::Widget trait! Learn allocate_exact_size, Sense::click, custom painting with the Painter API, and how to use your widget with ui.add(). Student code: https://github.com/GoCelesteAI/egui_custom_widgets/tree/main What You'll Learn: - impl egui::Widget trait for custom widgets - fn ui(self, ui: &mut Ui) - Response method signature - allocate_exact_size for reserving widget space - Sense::click() for click interaction - response.clicked() to toggle state - Custom painting with ui.painter() - rect_filled for rounded background - circle_filled for the sliding knob - Lifetime parameters for borrowed data - ui.add(Toggle::new(...)) usage pattern - Reusing the same widget for multiple settings - Dark/light theme toggle with set_visuals Timestamps: 0:00 Intro 0:12 App Preview 0:22 What We're Building 0:54 Create Project & Cargo.toml 1:26 main.rs — mod app & mod toggle 2:01 toggle.rs — Toggle Struct with Lifetime 2:24 impl new() Constructor 2:44 impl egui::Widget — fn ui() 3:14 allocate_exact_size & Sense::click 3:44 Custom Painting — Background & Circle 4:42 Return Response 5:08 app.rs — use crate::toggle::Toggle 5:28 MyApp Struct & Default 5:54 impl App — Dark/Light Visuals 6:20 Grid with Four Toggle Widgets 7:20 Status Label & Close 7:44 cargo build & Neo-tree Browse 8:10 App Demo 8:51 Recap 9:31 Next Episode Series: Learn egui in Neovim Part of a 36-episode series teaching Rust GUI development with egui, coded entirely in Neovim with Neo-tree. Tags: egui, rust, gui, custom widget, toggle switch, impl widget, tutorial, neovim, painter, allocate_exact_size, sense click, reusable component