Filmstrip: show every selected photo as selected, not only the active one (#298)

After Select All in the loupe only the active filmstrip cell was highlighted,
so the selection looked like a single photo. Cells now use Selection::state_of;
selected-but-not-active cells get the selected fill and a grey outline.

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

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

@@ -1526,9 +1526,10 @@ pub(crate) fn filmstrip(app: &mut LightcraftApp, ui: &mut egui::Ui, r: Rect) {
             }
             let resp = ui.interact(cr, egui::Id::new(("film", id.0)), Sense::click());
             register(ui.ctx(), format!("film:{}", id.0), cr);
-            let sel = Some(*id) == active;
+            let state = app.session.selection.state_of(*id);
+            let sel = state == lightcraft_engine::SelectionState::Active;
             let p = ui.painter();
-            if sel {
+            if state != lightcraft_engine::SelectionState::NotSelected {
                 p.rect_filled(cr, 0.0, t.cell_selected);
             } else if resp.hovered() {
                 p.rect_filled(cr, 0.0, t.cell_selected.gamma_multiply(0.6));
@@ -1549,6 +1550,8 @@ pub(crate) fn filmstrip(app: &mut LightcraftApp, ui: &mut egui::Ui, r: Rect) {
                 p.image(tex.tex.id(), fr, Rect::from_min_max(pos2(0.0, 0.0), pos2(1.0, 1.0)), Color32::WHITE);
                 if sel {
                     p.rect_stroke(fr, 0.0, Stroke::new(1.5, Color32::WHITE), StrokeKind::Outside);
+                } else if state == lightcraft_engine::SelectionState::Selected {
+                    p.rect_stroke(fr, 0.0, Stroke::new(1.5, Color32::from_gray(170)), StrokeKind::Outside);
                 }
                 if app.ui.settings.film_badges
                     && let Some(ph) = app.session.catalog.photo(*id)

crates/ui-egui/src/tests_panels.rs

@@ -199,3 +199,31 @@ fn sidebar_sections_collapse_and_remember_it() {
     click(&mut h, "icon:albumNew");
     assert!(!h.app.ui.sidebar_section_collapsed("albums"), "the plus does not fold Albums");
 }
+
+/// Select All in the loupe: every filmstrip cell of a selected photo is drawn selected, not just
+/// the active one (issue #298).
+#[test]
+fn filmstrip_marks_every_selected_photo() {
+    let mut h = demo([1400.0, 900.0], json!({"view": "detail"}));
+    let r = h.request("ui.key", json!({"key": "a", "cmd": true}), T);
+    assert_eq!(r["ok"], true, "{r}");
+    let img = h.snapshot(SETTLE);
+    assert_eq!(h.view.ctx.pixels_per_point(), 1.0, "the test samples pixels at point coordinates");
+    let active = h.app.session.selection.active.expect("active photo");
+    let t = crate::theme::Tokens::get(&h.view.ctx);
+    let ids = h.app.session.visible_cloned();
+    assert!(ids.len() > 3 && h.app.session.selection.ids.len() == ids.len());
+    let mut checked = 0;
+    for id in ids.iter().filter(|id| **id != active) {
+        let Some(r) = h.app.widgets.iter().find(|(w, _)| *w == format!("film:{}", id.0)).map(|(_, r)| *r) else { continue };
+        // cells scrolled under the right panel (default width plus the tool rail) are not visible
+        if r.max.x > 1400.0 - RIGHT_WIDTH.default - 48.0 {
+            continue;
+        }
+        // a pixel in the cell's left margin at mid height, clear of the name text and the thumbnail
+        let (x, y) = ((r.min.x + 4.0) as usize, r.center().y as usize);
+        assert_eq!(img[(x, y)], t.cell_selected, "film cell of selected photo {} is drawn selected", id.0);
+        checked += 1;
+    }
+    assert!(checked >= 3, "checked {checked} cells");
+}