fix(ui): preserve presentation display state when applying preferences

crates/ui-egui/src/canvas/zoom.rs

@@ -62,6 +62,11 @@ impl DocView {
         })
     }
 
+    /// The display saved before entering full screen, while presenting.
+    pub fn saved_display_mut(&mut self) -> Option<&mut SavedDisplay> {
+        self.presentation.as_mut()
+    }
+
     /// Whether the view is in full screen's one-page-at-a-time display.
     pub fn presenting(&self) -> bool {
         self.presentation.is_some()

crates/ui-egui/src/dialogs/preferences.rs

@@ -755,33 +755,62 @@ fn card_documents_and_view(ui: &mut egui::Ui, app: &mut PdfCraftApp, t: &Tokens,
     if app.always_default_view && (always_changed || layout_changed || continuous_changed || gaps_changed || fit_changed || zoom_changed) {
         let defaults = app.view_defaults;
         for view in &mut app.views {
-            view.set_display(defaults.layout, defaults.continuous);
             view.set_page_gaps(defaults.show_page_gaps);
-            match defaults.fit {
-                Fit::None => view.set_zoom(defaults.zoom),
-                fit if view.fit != fit => view.set_fit(fit),
-                _ => {}
+            if let Some(saved) = view.saved_display_mut() {
+                saved.layout = defaults.layout;
+                saved.continuous = defaults.continuous;
+                saved.fit = defaults.fit;
+                if defaults.fit == Fit::None {
+                    saved.zoom = defaults.zoom;
+                }
+            } else {
+                view.set_display(defaults.layout, defaults.continuous);
+                match defaults.fit {
+                    Fit::None => view.set_zoom(defaults.zoom),
+                    fit if view.fit != fit => view.set_fit(fit),
+                    _ => {}
+                }
             }
         }
     } else if let Some(i) = app.active {
-        if layout_changed {
-            app.views[i].set_layout(layout_choice);
-        }
-        if continuous_changed {
-            app.views[i].set_continuous(continuous);
-        }
+        let view = &mut app.views[i];
         if gaps_changed {
-            app.views[i].set_page_gaps(show_page_gaps);
+            view.set_page_gaps(show_page_gaps);
         }
-        if fit_changed {
-            match app.view_defaults.fit {
-                Fit::None => app.views[i].set_zoom(app.view_defaults.zoom),
-                fit if app.views[i].fit != fit => app.views[i].set_fit(fit),
-                _ => {}
+        if let Some(saved) = view.saved_display_mut() {
+            if layout_changed {
+                saved.layout = layout_choice;
+            }
+            if continuous_changed {
+                saved.continuous = continuous;
+            }
+            if fit_changed {
+                saved.fit = app.view_defaults.fit;
+                if app.view_defaults.fit == Fit::None {
+                    saved.zoom = app.view_defaults.zoom;
+                }
+            }
+            if zoom_changed {
+                saved.fit = Fit::None;
+                saved.zoom = app.view_defaults.zoom;
+            }
+        } else {
+            if layout_changed {
+                view.set_layout(layout_choice);
+            }
+            if continuous_changed {
+                view.set_continuous(continuous);
+            }
+            if fit_changed {
+                match app.view_defaults.fit {
+                    Fit::None => view.set_zoom(app.view_defaults.zoom),
+                    fit if view.fit != fit => view.set_fit(fit),
+                    _ => {}
+                }
+            }
+            if zoom_changed {
+                view.set_zoom(app.view_defaults.zoom);
             }
-        }
-        if zoom_changed {
-            app.views[i].set_zoom(app.view_defaults.zoom);
         }
     }
     ctx.checkbox(ui, &mut app.text_links, tl!("Open web and email addresses written in the page text"), t);

crates/ui-egui/tests/it/view.rs

@@ -1296,6 +1296,85 @@ fn preferences_toggle_continuous_scrolling_updates_active_document() {
     assert!(h.state().views[0].continuous(), "active document view is updated");
 }
 
+#[test]
+fn preferences_during_full_screen_updates_saved_normal_display_and_restores_on_exit() {
+    use egui_kittest::kittest::Queryable;
+    use pdfcraft_ui_egui::canvas::Fit;
+
+    let mut h = harness(&[("continuous", "off"), ("zoom", "50")]);
+    let v0 = &h.state().views[0];
+    assert!(!v0.continuous());
+    assert_eq!(v0.fit, Fit::None);
+    assert_eq!(v0.zoom, 0.5);
+
+    h.state_mut().views[0].enter_presentation();
+    assert!(h.state().views[0].presenting());
+    assert!(!h.state().views[0].continuous());
+    assert_eq!(h.state().views[0].fit, Fit::Page);
+
+    assert!(h.state_mut().execute("app.preferences"));
+    h.run_steps(3);
+    h.get_by_label("Always use my default zoom and page layout").scroll_to_me();
+    h.run_steps(4);
+    h.get_by_label("Always use my default zoom and page layout").click();
+    h.run_steps(2);
+    assert!(h.state().always_default_view);
+
+    {
+        let v = &h.state().views[0];
+        assert!(v.presenting(), "presentation display is preserved");
+        assert!(!v.continuous(), "presentation display is not continuous");
+        assert_eq!(v.fit, Fit::Page, "presentation display stays fitted to page");
+        assert!(v.normal_display().continuous, "saved normal display updated to continuous");
+        assert_eq!(v.normal_display().fit, Fit::Width, "saved normal display updated to default fit width");
+    }
+
+    h.state_mut().views[0].leave_presentation();
+    {
+        let v = &h.state().views[0];
+        assert!(!v.presenting());
+        assert!(v.continuous(), "continuous scrolling restored from updated preferences");
+        assert_eq!(v.fit, Fit::Width, "fit width restored from updated preferences");
+    }
+}
+
+#[test]
+fn preferences_toggle_continuous_during_full_screen_updates_saved_normal_display() {
+    use egui_kittest::kittest::Queryable;
+    use pdfcraft_ui_egui::canvas::Fit;
+
+    let mut h = harness(&[("default-continuous", "off"), ("continuous", "off")]);
+    assert!(!h.state().views[0].continuous());
+
+    h.state_mut().views[0].enter_presentation();
+    assert!(h.state().views[0].presenting());
+    assert!(!h.state().views[0].continuous());
+    assert_eq!(h.state().views[0].fit, Fit::Page);
+
+    assert!(h.state_mut().execute("app.preferences"));
+    h.run_steps(3);
+    h.get_by_label("Continuous scrolling").scroll_to_me();
+    h.run_steps(4);
+    h.get_by_label("Continuous scrolling").click();
+    h.run_steps(2);
+
+    assert!(h.state().view_defaults.continuous);
+    {
+        let v = &h.state().views[0];
+        assert!(v.presenting(), "presentation display is preserved");
+        assert!(!v.continuous(), "presentation display is not continuous");
+        assert_eq!(v.fit, Fit::Page, "presentation display stays fitted to page");
+        assert!(v.normal_display().continuous, "saved normal display updated to continuous");
+    }
+
+    h.state_mut().views[0].leave_presentation();
+    {
+        let v = &h.state().views[0];
+        assert!(!v.presenting());
+        assert!(v.continuous(), "continuous scrolling restored on exit");
+    }
+}
+
 #[test]
 fn preferences_set_the_default_zoom() {
     use egui_kittest::kittest::Queryable;