64 lines
1.6 KiB
Dart
64 lines
1.6 KiB
Dart
import 'dart:math';
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import 'package:equatable/equatable.dart';
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import 'package:flutter/foundation.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 double west, south, east, north, zoom;
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List<double> get boundingBox => [west, south, east, north];
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LatLng get center => LatLng((north + south) / 2, (east + west) / 2);
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@override
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List<Object?> get props => [west, south, east, north, zoom];
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const ZoomedBounds({
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required this.west,
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required this.south,
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required this.east,
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required this.north,
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required this.zoom,
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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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west: west,
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south: south,
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east: east,
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north: north,
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zoom: zoom,
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);
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}
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}
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