Implement lineOverlap, booleanOverlap, refactoring and bug fixes (#174)

* implement lineOverlap, booleanOverlap, refactoring and bugFixes

* minor updates

* clearing up nisses mischief

* update dependency: turf_equality

Author: jsiedentop

README.md

@@ -147,7 +147,7 @@ Any new benchmarks must be named `*_benchmark.dart` and reside in the
 - [ ] lineArc
 - [ ] lineChunk
 - [ ] [lineIntersect](https://github.com/dartclub/turf_dart/blob/main/lib/src/line_intersect.dart)
-- [ ] lineOverlap
+- [x] [lineOverlap](https://github.com/dartclub/turf_dart/blob/main/lib/src/line_overlap.dart)
 - [x] [lineSegment](https://github.com/dartclub/turf_dart/blob/main/lib/src/line_segment.dart)
 - [x] [lineSlice](https://github.com/dartclub/turf_dart/blob/main/lib/src/line_slice.dart)
 - [ ] lineSliceAlong
@@ -233,7 +233,7 @@ Any new benchmarks must be named `*_benchmark.dart` and reside in the
 - [x] [booleanDisjoint](https://github.com/dartclub/turf_dart/blob/main/lib/src/booleans/boolean_disjoint.dart)
 - [x] [booleanEqual](https://github.com/dartclub/turf_dart/blob/main/lib/src/booleans/boolean_equal.dart)
 - [x] [booleanIntersects](https://github.com/dartclub/turf_dart/blob/main/lib/src/booleans/boolean_intersects.dart)
-- [ ] booleanOverlap
+- [x] [booleanOverlap](https://github.com/dartclub/turf_dart/blob/main/lib/src/booleans/boolean_overlap.dart)
 - [x] [booleanParallel](https://github.com/dartclub/turf_dart/blob/main/lib/src/booleans/boolean_parallel.dart)
 - [x] [booleanPointInPolygon](https://github.com/dartclub/turf_dart/blob/main/lib/src/booleans/boolean_point_in_polygon.dart)
 - [x] [booleanPointOnLine](https://github.com/dartclub/turf_dart/blob/main/lib/src/booleans/boolean_point_on_line.dart)

lib/boolean.dart

@@ -7,7 +7,7 @@ export 'src/booleans/boolean_crosses.dart';
 export 'src/booleans/boolean_disjoint.dart';
 export 'src/booleans/boolean_equal.dart';
 export 'src/booleans/boolean_intersects.dart';
-// export 'src/booleans/boolean_overlap.dart';
+export 'src/booleans/boolean_overlap.dart';
 export 'src/booleans/boolean_parallel.dart';
 export 'src/booleans/boolean_point_in_polygon.dart';
 export 'src/booleans/boolean_point_on_line.dart';

lib/line_overlap.dart

@@ -0,0 +1,3 @@
+library turf_line_overlap;
+
+export "src/line_overlap.dart";

lib/src/booleans/boolean_contains.dart

@@ -1,8 +1,5 @@
 import 'package:turf/src/invariant.dart';
 import 'package:turf/turf.dart';
-
-import 'boolean_point_in_polygon.dart';
-import 'boolean_point_on_line.dart';
 import 'boolean_helper.dart';
 
 /// [booleanContains] returns [true] if the second geometry is completely contained
@@ -32,15 +29,15 @@ bool booleanContains(GeoJSONObject feature1, GeoJSONObject feature2) {
     if (geom2 is Point) {
       return coords1 == coords2;
     } else {
-      throw FeatureNotSupported(geom1, geom2);
+      throw GeometryCombinationNotSupported(geom1, geom2);
     }
   } else if (geom1 is MultiPoint) {
     if (geom2 is Point) {
       return isPointInMultiPoint(geom2, geom1);
     } else if (geom2 is MultiPoint) {
       return isMultiPointInMultiPoint(geom2, geom1);
     } else {
-      throw FeatureNotSupported(geom1, geom2);
+      throw GeometryCombinationNotSupported(geom1, geom2);
     }
   } else if (geom1 is LineString) {
     if (geom2 is Point) {
@@ -50,7 +47,7 @@ bool booleanContains(GeoJSONObject feature1, GeoJSONObject feature2) {
     } else if (geom2 is MultiPoint) {
       return isMultiPointOnLine(geom2, geom1);
     } else {
-      throw FeatureNotSupported(geom1, geom2);
+      throw GeometryCombinationNotSupported(geom1, geom2);
     }
   } else if (geom1 is Polygon) {
     if (geom2 is Point) {
@@ -63,10 +60,10 @@ bool booleanContains(GeoJSONObject feature1, GeoJSONObject feature2) {
     } else if (geom2 is MultiPoint) {
       return isMultiPointInPolygon(geom2, geom1);
     } else {
-      throw FeatureNotSupported(geom1, geom2);
+      throw GeometryCombinationNotSupported(geom1, geom2);
     }
   } else {
-    throw FeatureNotSupported(geom1, geom2);
+    throw GeometryCombinationNotSupported(geom1, geom2);
   }
 }
 

lib/src/booleans/boolean_helper.dart

@@ -4,15 +4,22 @@ import 'package:turf/src/bbox.dart';
 import 'boolean_point_on_line.dart';
 import 'boolean_point_in_polygon.dart';
 
-class FeatureNotSupported implements Exception {
+class GeometryNotSupported implements Exception {
+  final GeometryObject geometry;
+  GeometryNotSupported(this.geometry);
+
+  @override
+  String toString() => "geometry not supported ($geometry).";
+}
+
+class GeometryCombinationNotSupported implements Exception {
   final GeometryObject geometry1;
   final GeometryObject geometry2;
 
-  FeatureNotSupported(this.geometry1, this.geometry2);
+  GeometryCombinationNotSupported(this.geometry1, this.geometry2);
 
   @override
-  String toString() =>
-      "feature geometry not supported ($geometry1, $geometry2).";
+  String toString() => "geometry not supported ($geometry1, $geometry2).";
 }
 
 bool isPointInMultiPoint(Point point, MultiPoint multipoint) {

lib/src/booleans/boolean_overlap.dart

@@ -0,0 +1,179 @@
+import 'package:turf/helpers.dart';
+import 'package:turf/line_overlap.dart';
+import 'package:turf/line_segment.dart';
+import 'package:turf/src/invariant.dart';
+import 'package:turf/src/line_intersect.dart';
+import 'package:turf_equality/turf_equality.dart';
+import 'boolean_helper.dart';
+
+/// Takes two geometries [firstFeature] and [secondFeature] and checks if they
+/// share an common area but are not completely contained by each other.
+///
+/// Supported Geometries are `Feature<MultiPoint>`, `Feature<LineString>`,
+/// `Feature<MultiLineString>`, `Feature<Polygon>`, `Feature<MultiPolygon>`.
+/// Features must be of the same type. LineString/MultiLineString and
+/// Polygon/MultiPolygon combinations are supported. If the Geometries are not
+/// supported an [GeometryNotSupported] or [GeometryCombinationNotSupported]
+/// error is thrown.
+///
+/// Returns false if [firstFeature] and [secondFeature] are equal.
+/// - MultiPoint: returns Returns true if the two MultiPoints share any point.
+/// - LineString: returns true if the two Lines share any line segment.
+/// - Polygon: returns true if the two Polygons intersect.
+///
+/// Example:
+/// ```dart
+///  final first = Polygon(coordinates: [
+///    [
+///      Position(0, 0),
+///      Position(0, 5),
+///      Position(5, 5),
+///      Position(5, 0),
+///      Position(0, 0)
+///    ]
+///  ]);
+///  final second = Polygon(coordinates: [
+///    [
+///      Position(1, 1),
+///      Position(1, 6),
+///      Position(6, 6),
+///      Position(6, 1),
+///      Position(1, 1)
+///    ]
+///  ]);
+///  final third = Polygon(coordinates: [
+///    [
+///      Position(10, 10),
+///      Position(10, 15),
+///      Position(15, 15),
+///      Position(15, 10),
+///      Position(10, 10)
+///    ]
+///  ]);
+///
+/// final isOverlapping = booleanOverlap(first, second);
+/// final isNotOverlapping = booleanOverlap(second, third);
+/// ```
+bool booleanOverlap(
+  Feature firstFeature,
+  Feature secondFeature,
+) {
+  final first = getGeom(firstFeature);
+  final second = getGeom(secondFeature);
+
+  _checkIfGeometryCombinationIsSupported(first, second);
+
+  final eq = Equality(
+    reversedGeometries: true,
+    shiftedPolygons: true,
+  );
+  if (eq.compare(first, second)) {
+    return false;
+  }
+
+  switch (first.runtimeType) {
+    case MultiPoint:
+      switch (second.runtimeType) {
+        case MultiPoint:
+          return _isMultiPointOverlapping(
+            first as MultiPoint,
+            second as MultiPoint,
+          );
+        default:
+          throw GeometryCombinationNotSupported(first, second);
+      }
+    case MultiLineString:
+    case LineString:
+      switch (second.runtimeType) {
+        case LineString:
+        case MultiLineString:
+          return _isLineOverlapping(first, second);
+        default:
+          throw GeometryCombinationNotSupported(first, second);
+      }
+    case MultiPolygon:
+    case Polygon:
+      switch (second.runtimeType) {
+        case Polygon:
+        case MultiPolygon:
+          return _isPolygonOverlapping(first, second);
+        default:
+          throw GeometryCombinationNotSupported(first, second);
+      }
+    default:
+      throw GeometryCombinationNotSupported(first, second);
+  }
+}
+
+bool _isGeometrySupported(GeometryObject geometry) =>
+    geometry is MultiPoint ||
+    geometry is LineString ||
+    geometry is MultiLineString ||
+    geometry is Polygon ||
+    geometry is MultiPolygon;
+
+void _checkIfGeometryCombinationIsSupported(
+  GeometryObject first,
+  GeometryObject second,
+) {
+  if (!_isGeometrySupported(first) || !_isGeometrySupported(second)) {
+    throw GeometryCombinationNotSupported(first, second);
+  }
+}
+
+void _checkIfGeometryIsSupported(GeometryObject geometry) {
+  if (!_isGeometrySupported(geometry)) {
+    throw GeometryNotSupported(geometry);
+  }
+}
+
+List<Feature<LineString>> _segmentsOfGeometry(GeometryObject geometry) {
+  _checkIfGeometryIsSupported(geometry);
+  List<Feature<LineString>> segments = [];
+  segmentEach(
+    geometry,
+    (Feature<LineString> segment, _, __, ___, ____) {
+      segments.add(segment);
+    },
+  );
+  return segments;
+}
+
+bool _isLineOverlapping(GeometryObject firstLine, GeometryObject secondLine) {
+  for (final firstSegment in _segmentsOfGeometry(firstLine)) {
+    for (final secondSegment in _segmentsOfGeometry(secondLine)) {
+      if (lineOverlap(firstSegment, secondSegment).features.isNotEmpty) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+bool _isPolygonOverlapping(
+  GeometryObject firstPolygon,
+  GeometryObject secondPolygon,
+) {
+  for (final firstSegment in _segmentsOfGeometry(firstPolygon)) {
+    for (final secondSegment in _segmentsOfGeometry(secondPolygon)) {
+      if (lineIntersect(firstSegment, secondSegment).features.isNotEmpty) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+bool _isMultiPointOverlapping(
+  MultiPoint first,
+  MultiPoint second,
+) {
+  for (final firstPoint in first.coordinates) {
+    for (final secondPoint in second.coordinates) {
+      if (firstPoint == secondPoint) {
+        return true;
+      }
+    }
+  }
+  return false;
+}

lib/src/booleans/boolean_within.dart

@@ -20,8 +20,7 @@ import 'boolean_helper.dart';
 ///     Position.of([1, 4])
 ///   ],
 /// );
-/// booleanWithin(point, line);
-/// //=true
+/// final isWithin = booleanWithin(point, line); // true
 /// ```
 bool booleanWithin(
   GeoJSONObject feature1,
@@ -43,7 +42,7 @@ bool booleanWithin(
         case MultiPolygon:
           return isPointInMultiPolygon(point, geom2 as MultiPolygon);
         default:
-          throw FeatureNotSupported(geom1, geom2);
+          throw GeometryCombinationNotSupported(geom1, geom2);
       }
     case MultiPoint:
       final multipoint = geom1 as MultiPoint;
@@ -57,7 +56,7 @@ bool booleanWithin(
         case MultiPolygon:
           return isMultiPointInMultiPolygon(multipoint, geom2 as MultiPolygon);
         default:
-          throw FeatureNotSupported(geom1, geom2);
+          throw GeometryCombinationNotSupported(geom1, geom2);
       }
     case LineString:
       final line = geom1 as LineString;
@@ -69,7 +68,7 @@ bool booleanWithin(
         case MultiPolygon:
           return isLineInMultiPolygon(line, geom2 as MultiPolygon);
         default:
-          throw FeatureNotSupported(geom1, geom2);
+          throw GeometryCombinationNotSupported(geom1, geom2);
       }
     case Polygon:
       final polygon = geom1 as Polygon;
@@ -79,9 +78,9 @@ bool booleanWithin(
         case MultiPolygon:
           return isPolygonInMultiPolygon(polygon, geom2 as MultiPolygon);
         default:
-          throw FeatureNotSupported(geom1, geom2);
+          throw GeometryCombinationNotSupported(geom1, geom2);
       }
     default:
-      throw FeatureNotSupported(geom1, geom2);
+      throw GeometryCombinationNotSupported(geom1, geom2);
   }
 }