Add button for switching to load/home screen

Nice on web to switch demos.

Author: MichaelGrupp

crates/maps/src/app.rs

@@ -44,6 +44,7 @@ pub enum ViewMode {
     Stacked,
     #[default]
     Aligned,
+    LoadScreen,
 }
 
 #[derive(Clone, Debug, Display, Default, PartialEq, EnumString, VariantNames)]

crates/maps/src/app_impl/central_panel.rs

@@ -253,15 +253,19 @@ impl AppState {
         }
     }
 
-    fn show_empty(&mut self, ui: &mut egui::Ui) {
+    fn show_load_screen(&mut self, ui: &mut egui::Ui) {
         ui.with_layout(
             egui::Layout::centered_and_justified(egui::Direction::TopDown),
             |ui| {
                 ui.horizontal_centered(|ui| {
                     ui.vertical_centered(|ui| {
                         let frac = if cfg!(target_arch = "wasm32") { 4. } else { 2. };
                         ui.add_space((ui.available_height() / frac - 100.).max(SPACE));
-                        ui.heading("No maps loaded.");
+                        if self.data.maps.is_empty() {
+                            ui.heading("No maps loaded.");
+                        } else {
+                            ui.heading("Select a view in the top bar or load more maps.");
+                        }
                         ui.add_space(2. * SPACE);
                         self.load_meta_button(ui);
                         ui.add_space(SPACE);
@@ -309,8 +313,7 @@ impl AppState {
                 viewport_rect = ui.clip_rect();
 
                 if self.data.maps.is_empty() {
-                    self.show_empty(ui);
-                    return;
+                    self.options.view_mode = ViewMode::LoadScreen;
                 }
 
                 match self.options.view_mode {
@@ -327,6 +330,9 @@ impl AppState {
                     ViewMode::Aligned => {
                         self.show_grid(ui);
                     }
+                    ViewMode::LoadScreen => {
+                        self.show_load_screen(ui);
+                    }
                 }
             });
 

crates/maps/src/app_impl/load_delete.rs

@@ -12,7 +12,7 @@ use crate::tiles::Pane;
 use maps_io_ros::{Meta, load_image};
 use maps_rendering::{ImagePyramid, TextureFilter};
 
-use crate::app::{AppState, Error};
+use crate::app::{AppState, Error, ViewMode};
 use crate::app_impl::compat::migrate_old_egui_color;
 use maps_io_ros::MapPose;
 use maps_io_ros::value_interpretation;
@@ -74,6 +74,9 @@ impl AppState {
         self.data.draw_order.add(name.clone());
         info!("Loaded map: {name}");
         self.status.unsaved_changes = true;
+        if self.options.view_mode == ViewMode::LoadScreen {
+            self.options.view_mode = ViewMode::default();
+        }
     }
 
     pub(crate) fn load_map(&mut self, meta: Meta) -> Result<String, Error> {

crates/maps/src/app_impl/menu_panel.rs

@@ -1,7 +1,7 @@
 use eframe::egui;
 use log::error;
 
-use crate::app::AppState;
+use crate::app::{AppState, ViewMode};
 use crate::app_impl::constants::SPACE;
 use crate::app_impl::ui_helpers::display_path;
 use crate::map_state::MapState;
@@ -118,7 +118,24 @@ impl AppState {
     }
 
     fn menu_content(&mut self, ui: &mut egui::Ui) {
-        ui.heading("Maps");
+        egui::Sides::new().show(
+            ui,
+            |ui_left| {
+                ui_left.heading("Maps");
+            },
+            |ui_right| {
+                ui_right.visuals_mut().widgets.inactive.weak_bg_fill =
+                    ui_right.visuals().window_fill();
+                if ui_right
+                    .button(egui::RichText::new("🏠").heading())
+                    .on_hover_text("Switch to load screen")
+                    .clicked()
+                {
+                    self.options.view_mode = ViewMode::LoadScreen;
+                }
+            },
+        );
+
         ui.add_space(SPACE);
         ui.horizontal(|ui| {
             self.load_meta_button(ui);

crates/maps/src/wasm/demo.rs

@@ -128,6 +128,7 @@ impl AppState {
             include_bytes!("../../data/doc/demo_scaled.png"),
             "Demo showcasing very large map images, with maps of the Cartographer Deutsches Museum dataset.",
         ) {
+            self.data.maps.clear();
             load_cartographer_demo(self);
         }
     }
@@ -140,6 +141,7 @@ impl AppState {
             include_bytes!("../../data/doc/demo_nav2_scaled.png"),
             "Demo showcasing a typical mobile robot warehouse scenario, with maps from the Nav2 demo.",
         ) {
+            self.data.maps.clear();
             load_nav2_demo(self);
         }
     }