Grid: selected photos whose thumbnail isn't drawn yet still show as selected (#298)

The grid and filmstrip now both ask Selection::state_of.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

crates/ui-egui/src/panels/grid.rs

@@ -471,7 +471,8 @@ fn cell(app: &mut LightcraftApp, ui: &mut egui::Ui, id: PhotoId, r: Rect, square
     let Some(photo) = app.session.catalog.photo(id).cloned() else { return };
     let resp = ui.interact(r, egui::Id::new(("cell", id.0)), Sense::click_and_drag());
     register(ui.ctx(), format!("thumb:{}", id.0), r);
-    let selected = app.session.selection.contains(id);
+    let state = app.session.selection.state_of(id);
+    let selected = state != lightcraft_engine::SelectionState::NotSelected;
     // screen readers: the file, then rating / flag / label
     let mut spoken = photo.file_name.clone();
     if photo.rating > 0 {
@@ -486,7 +487,7 @@ fn cell(app: &mut LightcraftApp, ui: &mut egui::Ui, id: PhotoId, r: Rect, square
         spoken.push_str(&format!(", {} label", app.session.catalog.label_name(l)));
     }
     resp.widget_info(|| egui::WidgetInfo::selected(egui::WidgetType::SelectableLabel, true, selected, &spoken));
-    let active = app.session.selection.active == Some(id);
+    let active = state == lightcraft_engine::SelectionState::Active;
     let p = ui.painter();
     let img_rect = if square {
         p.rect_filled(r, 0.0, if selected { t.cell_selected } else { t.cell });
@@ -514,6 +515,12 @@ fn cell(app: &mut LightcraftApp, ui: &mut egui::Ui, id: PhotoId, r: Rect, square
     } else {
         let ph = img_rect.shrink(if square { 20.0 } else { 0.0 });
         p.rect_filled(ph, 0.0, Color32::from_gray(38));
+        // not drawn yet (or unreadable): the selection is still visible
+        if active {
+            p.rect_stroke(ph, 0.0, Stroke::new(2.0, Color32::WHITE), StrokeKind::Outside);
+        } else if selected {
+            p.rect_stroke(ph, 0.0, Stroke::new(2.0, Color32::from_gray(170)), StrokeKind::Outside);
+        }
         if app.renderer.failure(Slot::Thumb(id)).is_some() {
             // unreadable / missing file
             p.text(ph.center(), Align2::CENTER_CENTER, "!", t.semibold(18.0), t.text_dim);

crates/ui-egui/src/tests_grid.rs

@@ -131,3 +131,27 @@ fn grid_headers_selection_scrolling_stacks_and_shape_changes() {
     assert!(after.height() > after.width(), "{after:?}");
     assert_cheap_frames(&mut h);
 }
+
+/// Selected photos whose thumbnails have not loaded (or can't) are still marked selected in the
+/// justified grid (issue #298): the active one white, the others grey.
+#[test]
+fn unloaded_thumbnails_show_their_selection() {
+    let mut h = grid(ViewMode::PhotoGrid);
+    h.request("engine.execute", json!({"command": "library.selectAll"}), T);
+    let img = h.snapshot(SETTLE);
+    assert_eq!(h.view.ctx.pixels_per_point(), 1.0);
+    let active = h.app.session.selection.active.expect("active");
+    let canvas = h.app.canvas_rect.expect("grid drawn");
+    let mut checked = 0;
+    for (w, r) in h.app.widgets.iter().filter(|(w, _)| w.starts_with("thumb:")) {
+        if !canvas.shrink(4.0).contains_rect(*r) || r.min.x < 6.0 {
+            continue;
+        }
+        let id = w.trim_start_matches("thumb:").parse::<u64>().unwrap();
+        let want = if id == active.0 { egui::Color32::WHITE } else { egui::Color32::from_gray(170) };
+        let px = img[((r.min.x - 1.0) as usize, r.center().y as usize)];
+        assert_eq!(px, want, "photo {id}");
+        checked += 1;
+    }
+    assert!(checked >= 3, "checked {checked}");
+}