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Cull offscreen map markers to keep panning performant #5

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Merged
dfalling merged 1 commit into from
May 25, 2026
Merged

Cull offscreen map markers to keep panning performant #5

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18 changes: 13 additions & 5 deletions src/map/MapScreen.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -85,10 +85,18 @@ export function MapScreen() {
});
}, [data?.elements]);

const elements = useMemo(
() => Array.from(elementsById.values()),
[elementsById],
);
// Only render markers whose location falls inside the last-known viewport.
// <Marker> is a native View — rendering offscreen ones still costs layout
// and reprojection on every camera frame, so we cull client-side.
const visibleElements = useMemo(() => {
if (!bounds) return [];
const {left, right, bottom, top} = bounds;
return Array.from(elementsById.values()).filter(el => {
if (!el.location) return false;
const {longitude: lng, latitude: lat} = el.location;
return lng >= left && lng <= right && lat >= bottom && lat <= top;
});
}, [elementsById, bounds]);

return (
<View style={styles.container}>
Expand All @@ -98,7 +106,7 @@ export function MapScreen() {
onRegionDidChange={onRegionDidChange}>
<Camera ref={cameraRef} initialViewState={{center: [0, 20], zoom: 1}} />
<UserLocation animated accuracy />
{elements.map(el =>
{visibleElements.map(el =>
el.location ? (
<Marker
key={el.id}
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