added a composition mode, to turn off auto generation

src/main.rs

@@ -89,8 +89,12 @@ impl Default for DungeonApp {
             hover_level_idx: None,
             hover_stair_idx: None,
         };
+        if app.settings.composition_mode {
+            app.enter_composition_layout();
+        } else {
             app.levels = generate_all_levels(&app.settings);
             app.refresh_stairs();
+        }
         app
     }
 }
@@ -136,7 +140,14 @@ impl eframe::App for DungeonApp {
         if panel_result.clear_clicked {
             self.push_undo_snapshot();
             self.clear_layout();
-        } else if panel_result.reset_clicked || panel_result.settings_changed {
+        } else if panel_result.reset_clicked {
+            self.push_undo_snapshot();
+            if self.settings.composition_mode {
+                self.enter_composition_layout();
+            } else {
+                self.regenerate_layout();
+            }
+        } else if panel_result.settings_changed && !self.settings.composition_mode {
             self.push_undo_snapshot();
             self.regenerate_layout();
         } else if panel_result.save_clicked {
@@ -164,9 +175,15 @@ impl eframe::App for DungeonApp {
             }
         } else if panel_result.new_level_clicked {
             self.push_undo_snapshot();
+            if self.settings.composition_mode {
+                self.levels.push(DungeonLayout::empty(
+                    self.settings.pack_rooms_without_corridors,
+                ));
+            } else {
                 self.levels
                     .push(generate_level(&self.settings, self.levels.len()));
                 self.refresh_stairs();
+            }
             self.settings.active_level_index = self.levels.len() - 1;
         }
         if ctx.input(|i| i.key_pressed(egui::Key::Delete) || i.key_pressed(egui::Key::Backspace)) {
@@ -237,7 +254,14 @@ impl eframe::App for DungeonApp {
             self.export_progress = None;
         }
 
-        draw_legend_panel(ctx, &mut self.settings.colorblind_mode);
+        if draw_legend_panel(ctx, &mut self.settings) {
+            self.push_undo_snapshot();
+            if self.settings.composition_mode {
+                self.enter_composition_layout();
+            } else {
+                self.regenerate_layout();
+            }
+        }
 
         egui::CentralPanel::default().show(ctx, |ui| {
             // Clear level hover state so it only reflects current frame.
@@ -444,6 +468,17 @@ impl DungeonApp {
         self.reset_transient_state();
     }
 
+    // Start composition mode with one empty level.
+    fn enter_composition_layout(&mut self) {
+        self.levels = vec![DungeonLayout::empty(
+            self.settings.pack_rooms_without_corridors,
+        )];
+        self.settings.active_level_index = 0;
+        self.settings.export_level_index = 0;
+        self.suppressed_auto_door_edges.clear();
+        self.reset_transient_state();
+    }
+
     // Regenerate the dungeon layout from current settings and reset drag state.
     fn regenerate_layout(&mut self) {
         self.drag_state = None;

src/ui.rs

@@ -125,6 +125,7 @@ pub struct UiSettings {
     pub room_hallway_window_percent: usize,
     pub allow_internal_windows: bool,
     pub colorblind_mode: bool,
+    pub composition_mode: bool,
     pub export_format: ExportFormat,
     pub mask_format: MaskFormat,
     pub export_width: u32,
@@ -190,6 +191,7 @@ impl Default for UiSettings {
             room_hallway_window_percent: 10,
             allow_internal_windows: false,
             colorblind_mode: false,
+            composition_mode: false,
             export_format: ExportFormat::Png,
             mask_format: MaskFormat::Png,
             export_width: 0,
@@ -323,23 +325,28 @@ pub fn draw_side_panel(
     result
 }
 
-// Draw the accessibility and legend panel.
+// Draw mode controls and the legend panel.
-pub fn draw_legend_panel(ctx: &egui::Context, colorblind_mode: &mut bool) {
+pub fn draw_legend_panel(ctx: &egui::Context, settings: &mut UiSettings) -> bool {
+    let mut composition_mode_changed = false;
+
     egui::SidePanel::right("legend_panel")
         .resizable(false)
         .min_width(180.0)
         .default_width(200.0)
         .show_separator_line(true)
         .show(ctx, |ui| {
-            ui.heading("Accessibility");
+            ui.heading("Modes");
             ui.add_space(6.0);
-            ui.checkbox(colorblind_mode, "Colorblind Mode");
+            ui.checkbox(&mut settings.colorblind_mode, "Colorblind Mode");
+            composition_mode_changed = ui
+                .checkbox(&mut settings.composition_mode, "Composition Mode")
+                .changed();
             ui.add_space(10.0);
             ui.separator();
             ui.add_space(8.0);
             ui.heading("Legend");
             ui.add_space(8.0);
-            if *colorblind_mode {
+            if settings.colorblind_mode {
                 draw_legend_entry_colorblind(ui, "Rooms", LegendStyle::Crosshatch);
                 draw_legend_entry_colorblind(ui, "Corridors", LegendStyle::Dots);
                 draw_legend_entry_colorblind(ui, "Walls", LegendStyle::SolidLine);
@@ -380,6 +387,8 @@ pub fn draw_legend_panel(ctx: &egui::Context, colorblind_mode: &mut bool) {
             ui.label("• Right click: Cancel add tool");
             ui.label("• Right click + drag: Resize hovered room");
         });
+
+    composition_mode_changed
 }
 
 // Draw level tabs and return the hovered tab index.