fitBounds() + more

flutter_map/lib/flutter_map.dart

@@ -1,8 +1,11 @@
 library leaflet_flutter;
 
+import 'dart:async';
+
 import 'package:flutter/widgets.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_map/flutter_map.dart';
+import 'package:flutter_map/src/core/point.dart';
 import 'package:flutter_map/src/geo/crs/crs.dart';
 import 'package:flutter_map/src/map/flutter_map_state.dart';
 import 'package:flutter_map/src/map/map.dart';
@@ -13,6 +16,8 @@ export 'src/layer/tile_layer.dart';
 export 'src/layer/marker_layer.dart';
 export 'src/layer/polyline_layer.dart';
 export 'src/geo/crs/crs.dart';
+export 'src/geo/latlng_bounds.dart';
+export 'package:flutter_map/src/core/point.dart';
 
 class FlutterMap extends StatefulWidget {
   /// A set of layers' options to used to create the layers on the map
@@ -45,11 +50,20 @@ class FlutterMap extends StatefulWidget {
 abstract class MapController {
   /// Moves the map to a specific location and zoom level
   void move(LatLng center, double zoom);
+  void fitBounds(
+    LatLngBounds bounds, {
+    FitBoundsOptions options,
+  });
+  bool get ready;
+  Future<Null> get onReady;
+  LatLng get center;
+  double get zoom;
 
   factory MapController() => new MapControllerImpl();
 }
 
 typedef TapCallback(LatLng point);
+typedef PositionCallback(MapPosition position);
 
 class MapOptions {
   final Crs crs;
@@ -60,6 +74,7 @@ class MapOptions {
   final bool debug;
   final bool interactive;
   final TapCallback onTap;
+  final PositionCallback onPositionChanged;
   LatLng center;
 
   MapOptions({
@@ -72,7 +87,26 @@ class MapOptions {
     this.debug = false,
     this.interactive = true,
     this.onTap,
+    this.onPositionChanged,
   }) {
     if (center == null) center = new LatLng(50.5, 30.51);
   }
 }
+
+class FitBoundsOptions {
+  final Point<double> padding;
+  final double maxZoom;
+  final double zoom;
+
+  const FitBoundsOptions({
+    this.padding = const Point<double>(0.0, 0.0),
+    this.maxZoom = 17.0,
+    this.zoom,
+  });
+}
+
+class MapPosition {
+  final LatLng center;
+  final double zoom;
+  MapPosition({this.center, this.zoom});
+}

flutter_map/lib/src/core/bounds.dart

@@ -37,5 +37,9 @@ class Bounds<T extends num> {
     );
   }
 
+  Point<T> get size {
+    return this.max - this.min;
+  }
+
   String toString() => "Bounds($min, $max)";
 }

flutter_map/lib/src/core/center_zoom.dart

@@ -0,0 +1,7 @@
+import 'package:latlong/latlong.dart';
+
+class CenterZoom {
+  final LatLng center;
+  final double zoom;
+  CenterZoom({this.center, this.zoom});
+}

flutter_map/lib/src/geo/crs/crs.dart

@@ -37,6 +37,10 @@ abstract class Crs {
     return 256 * math.pow(2, zoom);
   }
 
+  num zoom(double scale) {
+    return math.log(scale / 256) / math.ln2;
+  }
+
   Bounds getProjectedBounds(double zoom) {
     if (this.infinite) return null;
 

flutter_map/lib/src/geo/latlng_bounds.dart

@@ -4,12 +4,15 @@ import 'package:latlong/latlong.dart';
 class LatLngBounds {
   LatLng sw;
   LatLng ne;
-  LatLngBounds(LatLng corner1, LatLng corner2) {
+  LatLngBounds([LatLng corner1, LatLng corner2]) {
     extend(corner1);
     extend(corner2);
   }
 
   void extend(LatLng latlng) {
+    if (latlng == null) {
+      return;
+    }
     _extend(latlng, latlng);
   }
 
@@ -28,4 +31,18 @@ class LatLngBounds {
       ne.longitude = math.max(ne2.longitude, ne.longitude);
     }
   }
+
+  double get west => southWest.longitude;
+  double get south => southWest.latitude;
+  double get east => northEast.longitude;
+  double get north => northEast.latitude;
+
+  LatLng get southWest => sw;
+  LatLng get northEast => ne;
+  LatLng get northWest => new LatLng(north, west);
+  LatLng get southEast => new LatLng(south, east);
+
+  bool get isValid {
+    return sw != null && ne != null;
+  }
 }

flutter_map/lib/src/layer/tile_layer.dart

@@ -1,5 +1,3 @@
-import 'dart:typed_data';
-
 import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
 import 'package:latlong/latlong.dart';

flutter_map/lib/src/map/map.dart

@@ -1,19 +1,43 @@
 import 'dart:async';
+import 'dart:math' as math;
 
+import 'package:flutter_map/src/core/center_zoom.dart';
 import 'package:latlong/latlong.dart';
 import 'package:flutter_map/flutter_map.dart';
 import 'package:flutter_map/src/core/bounds.dart';
 import 'package:flutter_map/src/core/point.dart';
 
 class MapControllerImpl implements MapController {
-  MapState state;
+  Completer<Null> _readyCompleter = new Completer<Null>();
+  MapState _state;
+
+  Future<Null> get onReady => _readyCompleter.future;
+  void set state(MapState state) {
+    _state = state;
+    if (!_readyCompleter.isCompleted) {
+      _readyCompleter.complete();
+    }
+  }
 
   void move(LatLng center, double zoom) {
-    state.move(center, zoom);
+    _state.move(center, zoom);
   }
+
+  void fitBounds(
+    LatLngBounds bounds, {
+    FitBoundsOptions options =
+        const FitBoundsOptions(padding: const Point(24.0, 24.0)),
+  }) {
+    _state.fitBounds(bounds, options);
+  }
+
+  bool get ready => _state != null;
+
+  LatLng get center => _state.center;
+  double get zoom => _state.zoom;
 }
 
-class MapState  {
+class MapState {
   final MapOptions options;
   final StreamController<Null> _onMoveSink;
 
@@ -60,6 +84,18 @@ class MapState  {
     _lastCenter = center;
     _pixelOrigin = getNewPixelOrigin(center);
     _onMoveSink.add(null);
+
+    if (options.onPositionChanged != null) {
+      options.onPositionChanged(new MapPosition(center: center, zoom: zoom));
+    }
+  }
+
+  void fitBounds(LatLngBounds bounds, FitBoundsOptions options) {
+    if (!bounds.isValid) {
+      throw ("Bounds are not valid.");
+    }
+    var target = _getBoundsCenterZoom(bounds, options);
+    move(target.center, target.zoom);
   }
 
   LatLng getCenter() {
@@ -69,6 +105,42 @@ class MapState  {
     return layerPointToLatLng(_centerLayerPoint);
   }
 
+  CenterZoom _getBoundsCenterZoom(
+      LatLngBounds bounds, FitBoundsOptions options) {
+    var paddingTL = options.padding;
+    var paddingBR = options.padding;
+
+    var zoom = getBoundsZoom(bounds, paddingTL + paddingBR, inside: false);
+    zoom = math.min(options.maxZoom, zoom);
+
+    var paddingOffset = (paddingBR - paddingTL) / 2;
+    var swPoint = project(bounds.southWest, zoom);
+    var nePoint = project(bounds.northEast, zoom);
+    var center = unproject((swPoint + nePoint) / 2 + paddingOffset, zoom);
+    return new CenterZoom(
+      center: center,
+      zoom: zoom,
+    );
+  }
+
+  double getBoundsZoom(LatLngBounds bounds, Point<double> padding,
+      {bool inside = false}) {
+    var zoom = this.zoom ?? 0.0;
+    var min = this.options.minZoom ?? 0.0;
+    var max = this.options.maxZoom ?? double.infinity;
+    var nw = bounds.northWest;
+    var se = bounds.southEast;
+    var size = this.size - padding;
+    var boundsSize = new Bounds(project(se, zoom), project(nw, zoom)).size;
+    var scaleX = size.x / boundsSize.x;
+    var scaleY = size.y / boundsSize.y;
+    var scale = inside ? math.max(scaleX, scaleY) : math.min(scaleX, scaleY);
+
+    zoom = getScaleZoom(scale, zoom);
+
+    return math.max(min, math.min(max, zoom));
+  }
+
   Point project(LatLng latlng, [double zoom]) {
     if (zoom == null) {
       zoom = _zoom;
@@ -97,6 +169,12 @@ class MapState  {
     return crs.scale(toZoom) / crs.scale(fromZoom);
   }
 
+  double getScaleZoom(double scale, double fromZoom) {
+    var crs = options.crs;
+    fromZoom = fromZoom == null ? _zoom : fromZoom;
+    return crs.zoom(scale * crs.scale(fromZoom));
+  }
+
   Bounds getPixelWorldBounds(double zoom) {
     return options.crs.getProjectedBounds(zoom == null ? _zoom : zoom);
   }

flutter_map/pubspec.yaml

@@ -13,5 +13,5 @@ dependencies:
     sdk: flutter
   latlong: ^0.4.0
   tuple: ^1.0.0
-  quiver: ^0.28.0
+  quiver: ^0.29.0
   transparent_image: ^0.1.0