106 lines
3.1 KiB
Dart
106 lines
3.1 KiB
Dart
import 'dart:math';
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import 'dart:ui';
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import 'package:aves_map/src/geo_utils.dart';
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import 'package:equatable/equatable.dart';
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import 'package:flutter/foundation.dart';
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import 'package:flutter_map/flutter_map.dart';
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import 'package:latlong2/latlong.dart';
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@immutable
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class ZoomedBounds extends Equatable {
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final LatLng sw, ne;
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final double zoom, rotation;
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// returns [southwestLng, southwestLat, northeastLng, northeastLat], as expected by Fluster
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List<double> get boundingBox => [sw.longitude, sw.latitude, ne.longitude, ne.latitude];
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// Map services (Google Maps, OpenStreetMap) use the spherical Mercator projection (EPSG 3857).
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static const _crs = Epsg3857();
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// The projected center appears visually in the middle of the bounds.
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LatLng get projectedCenter {
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final swPoint = _crs.latLngToPoint(sw, zoom);
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final nePoint = _crs.latLngToPoint(ne, zoom);
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// assume no padding around bounds
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final projectedCenter = _crs.pointToLatLng((swPoint + nePoint) / 2, zoom);
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return projectedCenter ?? GeoUtils.getLatLngCenter([sw, ne]);
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}
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@override
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List<Object?> get props => [sw, ne, zoom, rotation];
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const ZoomedBounds({
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required this.sw,
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required this.ne,
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required this.zoom,
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required this.rotation,
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});
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static const _collocationMaxDeltaThreshold = 360 / (2 << 19);
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factory ZoomedBounds.fromPoints({
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required Set<LatLng> points,
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double collocationZoom = 20,
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}) {
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var west = .0, south = .0, east = .0, north = .0;
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var zoom = collocationZoom;
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if (points.isNotEmpty) {
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final first = points.first;
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west = first.longitude;
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south = first.latitude;
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east = first.longitude;
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north = first.latitude;
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for (var point in points) {
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final lng = point.longitude;
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final lat = point.latitude;
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if (lng < west) west = lng;
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if (lat < south) south = lat;
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if (lng > east) east = lng;
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if (lat > north) north = lat;
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}
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final boundsDelta = max(north - south, east - west);
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if (boundsDelta > _collocationMaxDeltaThreshold) {
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zoom = max(1, log(360) / ln2 - log(boundsDelta) / ln2);
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}
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}
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return ZoomedBounds(
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sw: LatLng(south, west),
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ne: LatLng(north, east),
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zoom: zoom,
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rotation: 0,
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);
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}
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ZoomedBounds copyWith({
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LatLng? sw,
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LatLng? ne,
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double? zoom,
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double? rotation,
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}) {
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return ZoomedBounds(
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sw: sw ?? this.sw,
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ne: ne ?? this.ne,
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zoom: zoom ?? this.zoom,
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rotation: rotation ?? this.rotation,
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);
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}
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bool contains(LatLng location) => GeoUtils.contains(sw, ne, location);
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Size toDisplaySize() {
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final swPoint = _crs.latLngToPoint(sw, zoom);
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final nePoint = _crs.latLngToPoint(ne, zoom);
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return Size((swPoint.x - nePoint.x).abs().toDouble(), (swPoint.y - nePoint.y).abs().toDouble());
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}
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Offset offset(LatLng location) {
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final swPoint = _crs.latLngToPoint(sw, zoom);
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final nePoint = _crs.latLngToPoint(ne, zoom);
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final point = _crs.latLngToPoint(location, zoom);
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return Offset((point.x - swPoint.x).toDouble(), (point.y - nePoint.y).toDouble());
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}
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}
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