persistent map with animated transitions and dimmed overview on detail pages

src/app.css

@@ -99,6 +99,30 @@
 	box-sizing: border-box;
 }
 
+/* page transitions: quick cross-fade for content; the map morphs separately */
+@media not (prefers-reduced-motion: reduce) {
+	::view-transition-old(root) {
+		animation: 110ms ease both vt-fade-out;
+	}
+	::view-transition-new(root) {
+		animation: 220ms ease 40ms both vt-fade-in;
+	}
+	::view-transition-group(streba-map) {
+		animation-duration: 320ms;
+		animation-timing-function: cubic-bezier(0.3, 0, 0.2, 1);
+	}
+}
+@keyframes vt-fade-out {
+	to {
+		opacity: 0;
+	}
+}
+@keyframes vt-fade-in {
+	from {
+		opacity: 0;
+	}
+}
+
 body {
 	margin: 0;
 	background: var(--page);

src/lib/components/Map.svelte

@@ -38,12 +38,16 @@
 	let {
 		tracks = [],
 		peaks = [],
-		height = '420px',
+		highlightId = null,
+		focus = null,
+		height = '100%',
 		onpeakclick,
 		onviewport
 	}: {
 		tracks?: MapTrack[];
 		peaks?: MapPeak[];
+		highlightId?: number | null;
+		focus?: [[number, number], [number, number]] | null;
 		height?: string;
 		onpeakclick?: (id: number) => void;
 		onviewport?: (view: Viewport) => void;
@@ -51,7 +55,7 @@
 
 	let container: HTMLDivElement;
 	let map: import('maplibre-gl').Map | undefined;
-	let lib: typeof import('maplibre-gl') | undefined;
+	let loaded = $state(false);
 	let currentDark: boolean | undefined;
 	let pendingTerrain: unknown = null;
 
@@ -59,6 +63,12 @@
 		map?.flyTo({ center: [lon, lat], zoom });
 	}
 
+	let reportFn: (() => void) | null = null;
+	/** Ask the map to re-announce its current viewport (used when a page starts listening). */
+	export function reportViewport() {
+		if (loaded) reportFn?.();
+	}
+
 	function peaksGeojson(): FeatureCollection {
 		return {
 			type: 'FeatureCollection',
@@ -76,11 +86,96 @@
 		};
 	}
 
-	// push new data into the peaks layer when peaks/climbed state changes
+	function tracksGeojson(dark: boolean): FeatureCollection {
+		return {
+			type: 'FeatureCollection',
+			features: tracks.map((track) => {
+				const color = typeColor(track.type ?? 'outdoor');
+				return {
+					type: 'Feature' as const,
+					properties: {
+						id: track.id ?? null,
+						name: track.name ?? '',
+						username: track.username ?? '',
+						type: track.type ?? '',
+						date: track.date ?? '',
+						distance_m: track.distance_m ?? 0,
+						color: dark ? color.dark : color.light,
+						dim: highlightId !== null && track.id !== highlightId
+					},
+					geometry: {
+						type: 'LineString' as const,
+						coordinates: track.latlngs.map(([lat, lon]) => [lon, lat])
+					}
+				};
+			})
+		};
+	}
+
+	function overviewBounds(): [[number, number], [number, number]] | null {
+		let minLat = Infinity,
+			minLon = Infinity,
+			maxLat = -Infinity,
+			maxLon = -Infinity;
+		for (const track of tracks) {
+			for (const [lat, lon] of track.latlngs) {
+				if (lat < minLat) minLat = lat;
+				if (lat > maxLat) maxLat = lat;
+				if (lon < minLon) minLon = lon;
+				if (lon > maxLon) maxLon = lon;
+			}
+		}
+		return Number.isFinite(minLat)
+			? [
+					[minLat, minLon],
+					[maxLat, maxLon]
+				]
+			: null;
+	}
+
+	function applyCamera(animate: boolean) {
+		if (!map) return;
+		const target = focus ?? overviewBounds();
+		if (!target) return;
+		map.fitBounds(
+			[
+				[target[0][1], target[0][0]],
+				[target[1][1], target[1][0]]
+			],
+			{ padding: 48, maxZoom: 14, duration: animate ? 1100 : 0 }
+		);
+	}
+
+	// keep sources in sync when data, highlight, or theme changes
 	$effect(() => {
 		void peaks;
-		const source = map?.getSource('peaks') as import('maplibre-gl').GeoJSONSource | undefined;
-		source?.setData(peaksGeojson());
+		if (!loaded) return;
+		(map?.getSource('peaks') as import('maplibre-gl').GeoJSONSource | undefined)?.setData(
+			peaksGeojson()
+		);
+	});
+	$effect(() => {
+		void tracks;
+		void highlightId;
+		if (!loaded) return;
+		(map?.getSource('tracks') as import('maplibre-gl').GeoJSONSource | undefined)?.setData(
+			tracksGeojson(currentDark ?? false)
+		);
+	});
+
+	// animate the camera when a page requests a new focus
+	let lastFocusKey: string | undefined;
+	$effect(() => {
+		const key = JSON.stringify(focus);
+		if (!loaded) return;
+		if (lastFocusKey === undefined) {
+			lastFocusKey = key;
+			return;
+		}
+		if (key !== lastFocusKey) {
+			lastFocusKey = key;
+			applyCamera(true);
+		}
 	});
 
 	// swap map style when the theme changes
@@ -117,44 +212,28 @@
 			firstSymbol
 		);
 
-		map.addSource('tracks', {
-			type: 'geojson',
-			data: {
-				type: 'FeatureCollection',
-				features: tracks.map((track) => {
-					const color = typeColor(track.type ?? 'outdoor');
-					return {
-						type: 'Feature' as const,
-						properties: {
-							id: track.id ?? null,
-							name: track.name ?? '',
-							username: track.username ?? '',
-							type: track.type ?? '',
-							date: track.date ?? '',
-							distance_m: track.distance_m ?? 0,
-							color: dark ? color.dark : color.light
-						},
-						geometry: {
-							type: 'LineString' as const,
-							coordinates: track.latlngs.map(([lat, lon]) => [lon, lat])
-						}
-					};
-				})
-			}
-		});
+		map.addSource('tracks', { type: 'geojson', data: tracksGeojson(dark) });
 		map.addLayer({
 			id: 'tracks-casing',
 			type: 'line',
 			source: 'tracks',
 			layout: { 'line-join': 'round', 'line-cap': 'round' },
-			paint: { 'line-color': dark ? '#1a1a19' : '#ffffff', 'line-width': 5, 'line-opacity': 0.6 }
+			paint: {
+				'line-color': dark ? '#1a1a19' : '#ffffff',
+				'line-width': 5,
+				'line-opacity': ['case', ['get', 'dim'], 0.08, 0.6]
+			}
 		});
 		map.addLayer({
 			id: 'tracks-line',
 			type: 'line',
 			source: 'tracks',
 			layout: { 'line-join': 'round', 'line-cap': 'round' },
-			paint: { 'line-color': ['get', 'color'], 'line-width': 2.5 }
+			paint: {
+				'line-color': ['get', 'color'],
+				'line-width': 2.5,
+				'line-opacity': ['case', ['get', 'dim'], 0.15, 1]
+			}
 		});
 		// invisible wide line so thin routes are easy to click
 		map.addLayer({
@@ -173,14 +252,9 @@
 			source: 'peaks',
 			paint: {
 				'circle-radius': ['interpolate', ['linear'], ['zoom'], 5, 5, 12, 9],
-				'circle-color': [
-					'case',
-					['get', 'climbed'],
-					'#0ca30c',
-					dark ? '#1a1a19' : '#fcfcfb'
-				],
+				'circle-color': ['case', ['get', 'climbed'], '#0ca30c', dark ? '#1a1a19' : '#fcfcfb'],
 				'circle-stroke-width': 1.5,
-				'circle-stroke-color': ['case', ['get', 'climbed'], '#0ca30c', dark ? '#898781' : '#898781']
+				'circle-stroke-color': ['case', ['get', 'climbed'], '#0ca30c', '#898781']
 			}
 		});
 		map.addLayer({
@@ -210,7 +284,6 @@
 		(async () => {
 			const maplibre = await import('maplibre-gl');
 			if (cancelled) return;
-			lib = maplibre;
 
 			currentDark = theme.isDark;
 			map = new maplibre.Map({
@@ -228,6 +301,12 @@
 			);
 
 			map.on('style.load', () => addLayers(currentDark ?? false));
+			map.once('load', () => {
+				loaded = true;
+				lastFocusKey = JSON.stringify(focus);
+				applyCamera(false);
+				report();
+			});
 
 			// peak interaction: click to toggle, hover for tooltip
 			const popup = new maplibre.Popup({
@@ -303,28 +382,19 @@
 				if (map) map.getCanvas().style.cursor = '';
 			});
 
-			if (onviewport) {
-				const report = () => {
-					if (!map) return;
-					const b = map.getBounds();
-					onviewport({
-						minLat: b.getSouth(),
-						minLon: b.getWest(),
-						maxLat: b.getNorth(),
-						maxLon: b.getEast(),
-						zoom: map.getZoom()
-					});
-				};
-				map.on('moveend', report);
-				map.once('load', report);
-			}
-
-			const bounds = new maplibre.LngLatBounds();
-			for (const track of tracks) for (const [lat, lon] of track.latlngs) bounds.extend([lon, lat]);
-			for (const p of peaks) bounds.extend([p.lon, p.lat]);
-			if (!bounds.isEmpty()) {
-				map.fitBounds(bounds, { padding: 40, maxZoom: 14, animate: false });
-			}
+			const report = () => {
+				if (!map) return;
+				const b = map.getBounds();
+				onviewport?.({
+					minLat: b.getSouth(),
+					minLon: b.getWest(),
+					maxLat: b.getNorth(),
+					maxLon: b.getEast(),
+					zoom: map.getZoom()
+				});
+			};
+			reportFn = report;
+			map.on('moveend', report);
 		})();
 		return () => {
 			cancelled = true;
@@ -348,9 +418,6 @@
 		border-radius: 0.5rem;
 		box-shadow: 0 1px 4px rgba(0, 0, 0, 0.18);
 	}
-	:global(.maplibregl-ctrl-group:not(:empty)) {
-		box-shadow: 0 1px 4px rgba(0, 0, 0, 0.18);
-	}
 	:global(.maplibregl-ctrl-group button + button) {
 		border-top: 1px solid var(--border);
 	}

src/lib/components/MapSlot.svelte

@@ -0,0 +1,23 @@
+<script lang="ts">
+	import { mapState } from '$lib/map-state.svelte';
+
+	let { height = '440px' }: { height?: string } = $props();
+	let el: HTMLDivElement;
+
+	// move the persistent map into this page's slot; return it on leave
+	$effect(() => {
+		if (mapState.carrier && el) {
+			mapState.attach(el);
+			return () => mapState.detach();
+		}
+	});
+</script>
+
+<div class="map-slot" bind:this={el} style:height></div>
+
+<style>
+	.map-slot {
+		width: 100%;
+		border-radius: 0.875rem;
+	}
+</style>

src/lib/map-state.svelte.ts

@@ -0,0 +1,107 @@
+// Shared state for the single persistent map instance hosted by the layout.
+// Pages configure what the map shows; the map itself never remounts, so
+// navigation animates changes instead of rebuilding the canvas.
+
+import type { MapPeak, MapTrack, Viewport } from '$lib/components/Map.svelte';
+
+type Bounds = [[number, number], [number, number]];
+
+let peaks = $state<MapPeak[]>([]);
+let highlightId = $state<number | null>(null);
+let focus = $state<Bounds | null>(null);
+let detailTrack = $state<MapTrack | null>(null);
+let carrier = $state<HTMLElement | null>(null);
+let active = $state(false);
+
+let home: HTMLElement | null = null;
+let peakClickHandler: ((id: number) => void) | null = null;
+let viewportHandler: ((view: Viewport) => void) | null = null;
+let flyToFn: ((lat: number, lon: number, zoom?: number) => void) | null = null;
+let reportFn: (() => void) | null = null;
+
+export const mapState = {
+	get peaks() {
+		return peaks;
+	},
+	get highlightId() {
+		return highlightId;
+	},
+	get focus() {
+		return focus;
+	},
+	get detailTrack() {
+		return detailTrack;
+	},
+	get carrier() {
+		return carrier;
+	},
+	get active() {
+		return active;
+	},
+
+	setPeaks(value: MapPeak[]) {
+		peaks = value;
+	},
+	setHighlight(id: number | null) {
+		highlightId = id;
+	},
+	setFocus(bounds: Bounds | null) {
+		focus = bounds;
+	},
+	setDetailTrack(track: MapTrack | null) {
+		detailTrack = track;
+	},
+	setHandlers(handlers: {
+		onpeakclick?: (id: number) => void;
+		onviewport?: (view: Viewport) => void;
+	}) {
+		peakClickHandler = handlers.onpeakclick ?? null;
+		viewportHandler = handlers.onviewport ?? null;
+	},
+	reset() {
+		peaks = [];
+		highlightId = null;
+		focus = null;
+		detailTrack = null;
+		peakClickHandler = null;
+		viewportHandler = null;
+	},
+
+	handlePeakClick(id: number) {
+		peakClickHandler?.(id);
+	},
+	handleViewport(view: Viewport) {
+		viewportHandler?.(view);
+	},
+
+	registerCarrier(el: HTMLElement, homeEl: HTMLElement) {
+		carrier = el;
+		home = homeEl;
+	},
+	registerFlyTo(fn: (lat: number, lon: number, zoom?: number) => void) {
+		flyToFn = fn;
+	},
+	flyTo(lat: number, lon: number, zoom?: number) {
+		flyToFn?.(lat, lon, zoom);
+	},
+	registerReport(fn: () => void) {
+		reportFn = fn;
+	},
+	/** Ask the map to announce its viewport to the current handler. */
+	requestViewport() {
+		reportFn?.();
+	},
+
+	attach(slot: HTMLElement) {
+		if (carrier) {
+			slot.appendChild(carrier);
+			active = true;
+		}
+	},
+	detach() {
+		if (carrier && home) {
+			home.appendChild(carrier);
+			active = false;
+		}
+	}
+};

src/routes/+layout.server.ts

@@ -1,5 +1,38 @@
+import { db } from '$lib/server/db';
 import type { LayoutServerLoad } from './$types';
 
 export const load: LayoutServerLoad = ({ locals }) => {
-	return { user: locals.user };
+	// the overview: every user's tracks, thinned for the persistent map
+	const rows = db
+		.prepare(
+			`SELECT a.id, a.name, a.type, a.date, a.distance_m, a.points, u.username
+			 FROM activities a JOIN users u ON u.id = a.user_id`
+		)
+		.all() as {
+		id: number;
+		name: string;
+		type: string;
+		date: string | null;
+		distance_m: number;
+		points: string;
+		username: string;
+	}[];
+	const tracks = rows.map((row) => {
+		const points = JSON.parse(row.points) as { lat: number; lon: number }[];
+		const step = Math.max(1, Math.floor(points.length / 300));
+		const latlngs = points
+			.filter((_, i) => i % step === 0 || i === points.length - 1)
+			.map((p) => [p.lat, p.lon] as [number, number]);
+		return {
+			id: row.id,
+			name: row.name,
+			username: row.username,
+			type: row.type,
+			date: row.date,
+			distance_m: row.distance_m,
+			latlngs
+		};
+	});
+
+	return { user: locals.user, tracks };
 };

src/routes/+layout.svelte

@@ -2,7 +2,51 @@
 	import '@fontsource-variable/inter';
 	import '../app.css';
 	import { page } from '$app/state';
+	import { onNavigate } from '$app/navigation';
 	import { theme } from '$lib/theme.svelte';
+	import { mapState } from '$lib/map-state.svelte';
+	import Map from '$lib/components/Map.svelte';
+
+	let mapHome: HTMLDivElement;
+	let mapCarrier: HTMLDivElement;
+
+	$effect(() => {
+		if (mapCarrier && mapHome) mapState.registerCarrier(mapCarrier, mapHome);
+	});
+
+	let mapComponent: Map | undefined = $state();
+	$effect(() => {
+		if (mapComponent) {
+			mapState.registerFlyTo((lat, lon, zoom) => mapComponent!.flyTo(lat, lon, zoom));
+			mapState.registerReport(() => mapComponent!.reportViewport());
+		}
+	});
+
+	// the current activity's full-resolution track replaces its thinned overview twin
+	const mapTracks = $derived.by(() => {
+		const detail = mapState.detailTrack;
+		if (!detail) return data.tracks;
+		let replaced = false;
+		const merged = data.tracks.map((t) => {
+			if (t.id === detail.id) {
+				replaced = true;
+				return detail;
+			}
+			return t;
+		});
+		return replaced ? merged : [...merged, detail];
+	});
+
+	// cross-fade page content on navigation (the map morphs on its own)
+	onNavigate((navigation) => {
+		if (!document.startViewTransition) return;
+		return new Promise((resolve) => {
+			document.startViewTransition(async () => {
+				resolve();
+				await navigation.complete;
+			});
+		});
+	});
 
 	const themeTitle = $derived(
 		theme.pref === 'auto'
@@ -95,6 +139,25 @@
 	{@render children()}
 </main>
 
+<!-- the persistent map lives here when no page is showing it -->
+<div class="map-home" bind:this={mapHome} aria-hidden={!mapState.active}>
+	<div
+		class="map-carrier"
+		bind:this={mapCarrier}
+		style:view-transition-name={mapState.active ? 'streba-map' : 'none'}
+	>
+		<Map
+			bind:this={mapComponent}
+			tracks={mapTracks}
+			peaks={mapState.peaks}
+			highlightId={mapState.highlightId}
+			focus={mapState.focus}
+			onpeakclick={(id) => mapState.handlePeakClick(id)}
+			onviewport={(view) => mapState.handleViewport(view)}
+		/>
+	</div>
+</div>
+
 <footer class="footer">Streba - the GPX analyser</footer>
 
 <style>
@@ -232,4 +295,19 @@
 		font-size: 0.8rem;
 		border-top: 1px solid var(--border);
 	}
+	/* parking spot for the map while no page shows it: kept alive, out of sight */
+	.map-home {
+		position: fixed;
+		top: 0;
+		left: 0;
+		width: 720px;
+		height: 440px;
+		visibility: hidden;
+		pointer-events: none;
+		z-index: -1;
+	}
+	.map-carrier {
+		width: 100%;
+		height: 100%;
+	}
 </style>

src/routes/+page.server.ts

@@ -1,43 +1,10 @@
-import { communityTotals, countAscents, db, listAllActivities, listAscents } from '$lib/server/db';
+import { communityTotals, countAscents, listAllActivities, listAscents } from '$lib/server/db';
 import type { PageServerLoad } from './$types';
 
 export const load: PageServerLoad = ({ locals }) => {
-	// every user's tracks, thinned for the overview map
-	const rows = db
-		.prepare(
-			`SELECT a.id, a.name, a.type, a.date, a.distance_m, a.points, u.username
-			 FROM activities a JOIN users u ON u.id = a.user_id`
-		)
-		.all() as {
-		id: number;
-		name: string;
-		type: string;
-		date: string | null;
-		distance_m: number;
-		points: string;
-		username: string;
-	}[];
-	const tracks = rows.map((row) => {
-		const points = JSON.parse(row.points) as { lat: number; lon: number }[];
-		const step = Math.max(1, Math.floor(points.length / 300));
-		const latlngs = points
-			.filter((_, i) => i % step === 0 || i === points.length - 1)
-			.map((p) => [p.lat, p.lon] as [number, number]);
-		return {
-			id: row.id,
-			name: row.name,
-			username: row.username,
-			type: row.type,
-			date: row.date,
-			distance_m: row.distance_m,
-			latlngs
-		};
-	});
-
 	const user = locals.user;
 	return {
 		activities: listAllActivities(),
-		tracks,
 		totals: communityTotals(),
 		mine: user
 			? {

src/routes/+page.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-	import Map from '$lib/components/Map.svelte';
+	import MapSlot from '$lib/components/MapSlot.svelte';
 	import StatTile from '$lib/components/StatTile.svelte';
 	import ActivityItem from '$lib/components/ActivityItem.svelte';
 	import { fmtDistance, fmtElevation } from '$lib/format';
@@ -37,7 +37,7 @@
 </div>
 
 <h2>Worldmap</h2>
-<Map tracks={data.tracks} height="440px" />
+<MapSlot height="440px" />
 
 <h2>Recent activities</h2>
 {#if data.activities.length === 0}

src/routes/activities/[id]/+page.svelte

@@ -1,9 +1,10 @@
 <script lang="ts">
 	import { enhance } from '$app/forms';
-	import Map from '$lib/components/Map.svelte';
+	import MapSlot from '$lib/components/MapSlot.svelte';
 	import ElevationChart from '$lib/components/ElevationChart.svelte';
 	import SpeedChart from '$lib/components/SpeedChart.svelte';
 	import StatTile from '$lib/components/StatTile.svelte';
+	import { mapState } from '$lib/map-state.svelte';
 	import { fmtDate, fmtDistance, fmtDuration, fmtElevation, fmtSpeed } from '$lib/format';
 
 	let { data } = $props();
@@ -12,6 +13,24 @@
 	const avgSpeed = $derived(
 		a.moving_s && a.moving_s > 0 ? fmtSpeed(a.distance_m / a.moving_s) : null
 	);
+
+	// the persistent map keeps the overview visible, dims the rest,
+	// and animates toward this activity
+	$effect(() => {
+		mapState.setDetailTrack({
+			id: a.id,
+			name: a.name,
+			username: a.username,
+			type: a.type,
+			date: a.date,
+			distance_m: a.distance_m,
+			latlngs: data.latlngs
+		});
+		mapState.setHighlight(a.id);
+		mapState.setPeaks(data.bagged);
+		mapState.setFocus(JSON.parse(a.bounds));
+		return () => mapState.reset();
+	});
 </script>
 
 <svelte:head>
@@ -62,11 +81,7 @@
 {/if}
 
 <h2>Map</h2>
-<Map
-	tracks={[{ name: a.name, type: a.type, latlngs: data.latlngs }]}
-	peaks={data.bagged}
-	height="440px"
-/>
+<MapSlot height="440px" />
 
 {#if data.profile.length > 1}
 	<h2>Elevation profile</h2>

src/routes/peaks/+page.svelte

@@ -1,5 +1,7 @@
 <script lang="ts">
-	import Map, { type Viewport } from '$lib/components/Map.svelte';
+	import MapSlot from '$lib/components/MapSlot.svelte';
+	import type { Viewport } from '$lib/components/Map.svelte';
+	import { mapState } from '$lib/map-state.svelte';
 	import { fmtDate } from '$lib/format';
 
 	let { data } = $props();
@@ -22,7 +24,6 @@
 	let viewPeaks: ViewPeak[] = $state([]);
 	let tab: 'view' | 'mine' = $state('view');
 	let loading = $state(false);
-	let mapRef: Map | undefined = $state();
 
 	// search
 	let query = $state('');
@@ -49,7 +50,7 @@
 	function goTo(peak: ViewPeak) {
 		searchOpen = false;
 		query = peak.name;
-		mapRef?.flyTo(peak.lat, peak.lon, 12.5);
+		mapState.flyTo(peak.lat, peak.lon, 12.5);
 	}
 
 	const LIST_CAP = 150;
@@ -69,6 +70,16 @@
 		confirmPeak = null;
 	}
 
+	// drive the persistent map: our peaks, our handlers, viewport-fed fetching
+	$effect(() => {
+		mapState.setPeaks(mapPeaks);
+	});
+	$effect(() => {
+		mapState.setHandlers({ onpeakclick: onMapPeakClick, onviewport });
+		mapState.requestViewport();
+		return () => mapState.reset();
+	});
+
 	const highest = $derived(ascents[0] ?? null);
 
 	const mapPeaks = $derived(
@@ -147,7 +158,7 @@
 	Zoom in to reveal less prominent summits; click a peak to cross it off.
 </p>
 
-<Map bind:this={mapRef} peaks={mapPeaks} height="480px" onpeakclick={onMapPeakClick} {onviewport} />
+<MapSlot height="480px" />
 
 <div class="search">
 	<input