eframe Window System

Overview

The main application window implementation using eframe/egui. Handles window lifecycle, dynamic title updates, responsive layout, and window state persistence.

Key Files

• src/app.rs - Main FerriteApp struct implementing eframe::App
• src/main.rs - Application entry point with eframe::run_native

Implementation Details

FerriteApp Structure

pub struct FerriteApp {
    state: AppState,              // Central application state
    should_exit: bool,            // Exit flag after confirmation
    last_window_size: Option<egui::Vec2>,  // For detecting changes
    last_window_pos: Option<egui::Pos2>,   // For detecting changes
}

Entry Point Configuration

The application is launched via eframe::run_native() with NativeOptions:

let viewport = egui::ViewportBuilder::default()
    .with_title(APP_NAME)
    .with_inner_size([window_size.width, window_size.height])
    .with_min_inner_size([400.0, 300.0])
    .with_position([x, y])  // If saved
    .with_maximized(maximized);

Dynamic Window Title

The window title updates reactively based on the active tab:

State	Title Format
New file	Untitled - Ferrite
Saved file	filename.md - Ferrite
Modified	filename.md* - Ferrite

Implementation uses ViewportCommand::Title:

ctx.send_viewport_cmd(egui::ViewportCommand::Title(title));

Window State Persistence

Window size and position are tracked and saved to settings:

1. update_window_state() monitors viewport changes
2. Changes detected via outer_rect from viewport info
3. Settings updated with new WindowSize values
4. Saved on application shutdown via AppState::shutdown()

Close Request Handling

The app intercepts close requests to check for unsaved changes:

if ctx.input(|i| i.viewport().close_requested()) {
    if !self.handle_close_request() {
        ctx.send_viewport_cmd(egui::ViewportCommand::CancelClose);
    }
}

UI Layout

Panel	Purpose
TopBottomPanel::top	Menu bar (File, Help)
TopBottomPanel::bottom	Status bar (message, cursor position)
CentralPanel	Main content area (tabs, editor placeholder)

Dialog Windows

• Confirmation Dialog: Unsaved changes on exit/close
• About Dialog: Application version and info

Dependencies Used

• eframe - Native application framework
• egui - Immediate mode GUI library
• log - Logging for debug/info messages

Usage

Run the application:

cargo run

The window will:

1. Load size/position from settings (or use defaults: 1200x800)
2. Display with menu bar, status bar, and tab bar
3. Track and save window state changes
4. Show confirmation dialog on exit if unsaved changes exist

Tests

This module uses manual testing:

1. Window sizing: Resize window → close → reopen → verify size restored
2. Position persistence: Move window → close → reopen → verify position
3. Title updates: Create tabs, modify content → verify title changes
4. Exit handling: Modify tab → try to close → verify confirmation dialog
5. Menu actions: File → New, Exit; Help → About

Related Documentation

• App State - AppState integration
• Settings & Config - WindowSize struct