egui/examples/dock/src/main.rs

#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release

use eframe::egui;
use egui::Color32;

use egui_extras::dock;

fn main() -> Result<(), eframe::Error> {
    env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
    let options = eframe::NativeOptions {
        initial_window_size: Some(egui::vec2(800.0, 600.0)),
        ..Default::default()
    };
    eframe::run_native(
        "Dock",
        options,
        Box::new(|cc| {
            let mut app = MyApp::default();
            if let Some(storage) = cc.storage {
                if let Some(state) = eframe::get_value(storage, eframe::APP_KEY) {
                    app = state;
                }
            }
            Box::new(app)
        }),
    )
}

#[derive(serde::Deserialize, serde::Serialize)]
pub struct View {
    title: String,
    color: Color32,
}

impl View {
    pub fn with_nr(i: usize) -> Self {
        Self {
            title: format!("View {i}"),
            color: egui::epaint::Hsva::new(0.1 * i as f32, 0.5, 0.5, 1.0).into(),
        }
    }

    pub fn ui(&mut self, ui: &mut egui::Ui) -> dock::UiResponse {
        ui.painter().rect_filled(ui.max_rect(), 0.0, self.color);
        let dragged = ui
            .add(
                egui::Button::new(format!("Contents of {}. Drag me!", self.title))
                    .sense(egui::Sense::drag()),
            )
            .on_hover_cursor(egui::CursorIcon::Grab)
            .dragged();
        if dragged {
            dock::UiResponse::DragStarted
        } else {
            dock::UiResponse::None
        }
    }
}

#[derive(Default)]
struct DockBehavior {
    simplification_options: dock::SimplificationOptions,
}

impl dock::Behavior<View> for DockBehavior {
    fn leaf_ui(
        &mut self,
        ui: &mut egui::Ui,
        _node_id: dock::NodeId,
        view: &mut View,
    ) -> dock::UiResponse {
        view.ui(ui)
    }

    fn tab_text_for_leaf(&mut self, view: &View) -> egui::WidgetText {
        view.title.clone().into()
    }

    fn simplification_options(&self) -> dock::SimplificationOptions {
        self.simplification_options
    }
}

#[derive(serde::Deserialize, serde::Serialize)]
struct MyApp {
    dock: dock::Dock<View>,

    #[serde(skip, default)]
    behavior: DockBehavior,
}

impl Default for MyApp {
    fn default() -> Self {
        let mut next_view_nr = 0;
        let mut gen_view = || {
            let view = View::with_nr(next_view_nr);
            next_view_nr += 1;
            view
        };

        let mut nodes = dock::Nodes::default();

        let tab0 = { nodes.insert_leaf(gen_view()) };
        let tab1 = {
            let a = nodes.insert_leaf(gen_view());
            let b = nodes.insert_leaf(gen_view());
            nodes.insert_tab_node(vec![a, b])
        };
        let tab2 = {
            let a = nodes.insert_leaf(gen_view());
            let b = nodes.insert_leaf(gen_view());
            let c = nodes.insert_leaf(gen_view());
            let d = nodes.insert_leaf(gen_view());
            let e = nodes.insert_leaf(gen_view());
            nodes.insert_horizontal_node(vec![a, b, c, d, e])
        };

        let root = nodes.insert_tab_node(vec![tab0, tab1, tab2]);

        let dock = dock::Dock::new(root, nodes);

        Self {
            dock,
            behavior: Default::default(),
        }
    }
}

impl eframe::App for MyApp {
    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
        egui::SidePanel::left("tree").show(ctx, |ui| {
            if ui.button("Reset").clicked() {
                *self = Default::default();
            }
            ui.checkbox(
                &mut self
                    .behavior
                    .simplification_options
                    .all_leaves_must_have_tabs,
                "All views have tabs",
            );
            ui.separator();

            tree_ui(ui, &mut self.behavior, &self.dock.nodes, self.dock.root);
        });

        egui::CentralPanel::default().show(ctx, |ui| {
            self.dock.ui(&mut self.behavior, ui);
        });
    }

    fn save(&mut self, storage: &mut dyn eframe::Storage) {
        eframe::set_value(storage, eframe::APP_KEY, &self);
    }
}

fn tree_ui(
    ui: &mut egui::Ui,
    behavior: &mut dyn dock::Behavior<View>,
    nodes: &dock::Nodes<View>,
    node_id: dock::NodeId,
) {
    let Some(node) = nodes.get(node_id) else { return; };

    // if let dock::NodeLayout::Leaf(view) = node {
    //     ui.label(&view.title);
    //     return;
    // }

    let text = format!(
        "{} - {node_id:?}",
        behavior.tab_text_for_node(nodes, node_id).text()
    );

    egui::CollapsingHeader::new(text)
        .id_source((node_id, "tree"))
        .default_open(true)
        .show(ui, |ui| match node {
            dock::Node::Leaf(_) => {}
            dock::Node::Branch(branch) => {
                for &child in &branch.children {
                    tree_ui(ui, behavior, nodes, child);
                }
            }
        });
}