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fix(a11y): label cluster markers and announce zoom-guard to screen readers #132

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Merged
yakew7 merged 1 commit into from
Aug 14, 2026
Merged

fix(a11y): label cluster markers and announce zoom-guard to screen readers #132

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44 changes: 37 additions & 7 deletions src/components/map/map-view.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@ import {
} from "react-leaflet";

import type { Place, PlaceType } from "@/lib/types";
import { PLACE_TYPES } from "@/lib/types";
import { PLACE_TYPES, PLACE_TYPE_LABELS } from "@/lib/types";
import type { LatLng } from "@/lib/geo";
import studyMapConfig from "../../../studymap.config";
import type { Bounds } from "@/lib/places";
Expand All @@ -31,7 +31,7 @@ function emptyTypeCounts(): ClusterAggProps {
}

/** Builds a pie-style divIcon: a conic-gradient ring colored by place type, count in the middle. */
function clusterIcon(counts: ClusterAggProps, total: number): L.DivIcon {
function clusterIcon(counts: ClusterAggProps, total: number, label: string): L.DivIcon {
let acc = 0;
const stops: string[] = [];
for (const type of PLACE_TYPES) {
Expand All @@ -44,13 +44,29 @@ function clusterIcon(counts: ClusterAggProps, total: number): L.DivIcon {
}
const size = total < 10 ? 36 : total < 50 ? 44 : 54;
return L.divIcon({
html: `<div class="cluster-pie" style="width:${size}px;height:${size}px;background:conic-gradient(${stops.join(", ")});box-sizing:border-box;"><span>${total}</span></div>`,
html: `<div class="cluster-pie" style="width:${size}px;height:${size}px;background:conic-gradient(${stops.join(", ")});box-sizing:border-box;" role="button" tabindex="0" aria-label="${label}"><span>${total}</span></div>`,
className: "cluster-pie-icon",
iconSize: [size, size],
iconAnchor: [size / 2, size / 2],
});
}

/** Summarizes a cluster's contents for assistive tech, e.g. "Cluster of 11 places, mostly SAT centre". */
function clusterLabel(counts: ClusterAggProps, total: number): string {
let dominant: PlaceType | null = null;
let dominantCount = 0;
for (const type of PLACE_TYPES) {
if (counts[type] > dominantCount) {
dominant = type;
dominantCount = counts[type];
}
}
if (!dominant || dominant === "other_places") {
return `Cluster of ${total} ${total === 1 ? "place" : "places"}`;
}
return `Cluster of ${total} ${total === 1 ? "place" : "places"}, mostly ${PLACE_TYPE_LABELS[dominant].toLowerCase()}`;
}

function pinIcon(color: string): L.DivIcon {
return L.divIcon({
html: `<div class="pin-marker" style="background-color:${color};"></div>`,
Expand Down Expand Up @@ -129,7 +145,7 @@ function ClusteredMarkers({ places }: { places: Place[] }) {
<Marker
key={`cluster-${clusterId}`}
position={[lat, lng]}
icon={clusterIcon(properties, count)}
icon={clusterIcon(properties, count, clusterLabel(properties, count))}
eventHandlers={{
click: () => {
const expansionZoom = Math.min(
Expand All @@ -138,6 +154,15 @@ function ClusteredMarkers({ places }: { places: Place[] }) {
);
map.flyTo([lat, lng], expansionZoom, { duration: 0.5 });
},
keydown: (e) => {
if (e.originalEvent.key !== "Enter" && e.originalEvent.key !== " ") return;
e.originalEvent.preventDefault();
const expansionZoom = Math.min(
index.getClusterExpansionZoom(clusterId),
18,
);
map.flyTo([lat, lng], expansionZoom, { duration: 0.5 });
},
}}
/>
);
Expand Down Expand Up @@ -290,9 +315,14 @@ function ScrollZoomGuard() {
}, [map]);

return (
<div className={`scroll-zoom-hint${hint ? " visible" : ""}`} aria-hidden>
Use Ctrl + scroll to zoom the map
</div>
<>
<div className={`scroll-zoom-hint${hint ? " visible" : ""}`} aria-hidden>
Use Ctrl + scroll to zoom the map
</div>
<span className="sr-only" role="note">
Zoom the map with the + and - keys, or Ctrl/Cmd + scroll
</span>
</>
);
}

Expand Down
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