Module chart_selection 

ChartSelection — point-level selection state for chart widgets.

ChartSelection manages which (series, point index) pairs are selected across a crate::ChartModel — the chart counterpart of crate::SelectionModel (flat lists) and crate::KeyedSelectionModel (keyed collections). It is a share-by-clone handle: pass a clone to each chart that should share selection state. The current selection is exposed as a reactive Signal<HashSet<(SeriesId, usize)>> so widgets can bind to it without polling.

HashSet (not BTreeSet) is used because SeriesId is intentionally not Ord (it’s an opaque SlotMap key, mirroring crate::NodeId) — there is no natural ordering across series, only within one series’ point indices. This is the same rationale as crate::KeyedSelectionModel, which uses HashSet<K> for the same reason.

Three selection behaviours are available via SelectionMode: None, Single, and Multi (toggle + anchor-based range extension). ChartSelection::extend_to only extends within the anchor’s own series — a cross-series “range” has no natural order, so it falls back to a single-point select. ChartSelection::adjust keeps selected points consistent as the source model mutates (series removed, points inserted/removed) — call it from your own model observer, or skip the wiring entirely with ChartSelection::attached (equivalently, ChartSelection::attach on an existing selection), which subscribes internally and calls adjust for you, the same way crate::ChartWindow/crate::ChartAggregate self-wire in their own constructors. Forgetting to wire adjust up manually otherwise leaves the selection silently stale after a mutation.

let model: ChartModel<i32> = ChartModel::new();
let s = model.add_series("s");
for i in 0..5 {
    model.push_point(s, i, i as f32);
}

let sel = ChartSelection::attached(SelectionMode::Multi, &model);
sel.select_point(s, 1);
sel.extend_to(s, 3);
assert_eq!(sel.count(), 3); // (s,1), (s,2), (s,3)

model.remove_point(s, 0); // upstream mutation — no manual adjust() call
assert_eq!(sel.count(), 3); // (s,0), (s,1), (s,2) — shifted down

sel.clear();
assert_eq!(sel.count(), 0);

Structs

ChartSelection

Point-level selection state for a chart, keyed by (series, point index). See module documentation for semantics.