Merge pull request #3167 from sungjea713/assets-tab-scrolls-to-checked

Export for Screens: the Assets tab scrolls to the assets it opens on

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

@@ -133,6 +133,10 @@ pub(crate) fn open_assets(app: &mut VectorcraftApp, checked: Option<&[u64]>) {
         d.fields.insert("tab".into(), json!("assets"));
         if let Some(c) = checked {
             d.fields.insert("assets".into(), json!(c));
+            // The list scrolls to the first of them once: new assets land at its end.
+            if let Some(first) = c.first() {
+                d.fields.insert("__scrollTo".into(), json!(first));
+            }
         }
     }
 }
@@ -544,9 +548,12 @@ fn assets(app: &VectorcraftApp, ui: &mut egui::Ui, d: &mut Dialog) {
             on.clear();
         }
     });
+    // Asked for until the row is in view: the dialog's first frame only measures it.
+    let scroll_to = d.fields.get("__scrollTo").and_then(Value::as_u64).filter(|id| st.doc.assets.iter().any(|a| a.id == *id));
+    let mut in_view = scroll_to.is_none();
     egui::ScrollArea::vertical().max_height(330.0).show(ui, |ui| {
         for a in &st.doc.assets {
-            ui.horizontal(|ui| {
+            let row = ui.horizontal(|ui| {
                 let (r, _) = ui.allocate_exact_size(egui::vec2(46.0, 46.0), egui::Sense::hover());
                 crate::panels::asset_export::paint_thumb(ui, st, a, r);
                 let checked = on.contains(&a.id);
@@ -557,8 +564,18 @@ fn assets(app: &VectorcraftApp, ui: &mut egui::Ui, d: &mut Dialog) {
                     }
                 }
             });
+            if scroll_to == Some(a.id) {
+                if ui.clip_rect().contains_rect(row.response.rect) {
+                    in_view = true;
+                } else {
+                    row.response.scroll_to_me(Some(egui::Align::Center));
+                }
+            }
         }
     });
+    if in_view {
+        d.fields.remove("__scrollTo");
+    }
     if on != before {
         d.fields.insert("assets".into(), json!(on));
     }

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

@@ -145,3 +145,38 @@ fn the_menus_reach_asset_export() {
     app.run("assets.add", json!({"multiple": false})).unwrap();
     assert_eq!(assets(&mut app).len(), 1);
 }
+
+/// The Assets tab opened on new assets scrolls its list to the first checked one, once: they land
+/// at the end of a long list.
+#[test]
+fn the_assets_tab_scrolls_to_the_new_asset() {
+    let (mut app, _, ids) = app(true);
+    for i in 0..30 {
+        let id = app.run("shape.rectangle", json!({"x": 5 * i, "y": 50, "width": 4, "height": 4})).unwrap()["id"].clone();
+        app.run("assets.add", json!({"ids": [id]})).unwrap();
+    }
+    app.run("select.set", json!({"ids": ids})).unwrap();
+    let r = app.run("file.exportSelection", json!({"multiple": false})).unwrap();
+    let new = r["assets"][0].clone();
+    assert_eq!(assets(&mut app).len(), 31);
+    assert_eq!(assets(&mut app).last().unwrap()["id"], new);
+    assert_eq!(field(&app, "__scrollTo"), new);
+    let name = assets(&mut app).last().unwrap()["name"].as_str().unwrap().to_string();
+    // The rows below the list's visible part are painted but clipped away: the new one is inside
+    // its clip once the frame after the opening one has scrolled.
+    let ctx = egui::Context::default();
+    crate::theme::install_fonts(&ctx);
+    let mut shown = false;
+    // Scrolling is animated: a second of frames lets it land.
+    for i in 0..60 {
+        let input = egui::RawInput { time: Some(f64::from(i) / 60.0), ..egui::RawInput::default() };
+        let mut out = ctx.run_ui(input, |ui| super::show(&mut app, ui.ctx()));
+        out.textures_delta.clear();
+        shown = out.shapes.iter().any(|c| match &c.shape {
+            egui::Shape::Text(t) => t.galley.text() == name && c.clip_rect.contains_rect(t.visual_bounding_rect()),
+            _ => false,
+        });
+    }
+    assert!(shown, "{name} is clipped out of the list");
+    assert_eq!(field(&app, "__scrollTo"), Value::Null, "scrolled once");
+}