Map circles (#7401)

* Add Circle to Maps * Add GeographyUtils class and Distance.BetweenPoints method * Added a unit test for Distance.BetweenPositions method * Convert .Find() and .ForEach() into for loops * Move code for converting a circle into a list of points into GeographyUtils, made EarthRadiusKm internal
xamarin · Jan 29, 2020 · 3f84ee0 · 3f84ee0
1 parent b486522
commit 3f84ee0
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Showing 10 changed files with 467 additions and 17 deletions.
diff --git a/Xamarin.Forms.Controls/GalleryPages/MapElementsGallery.xaml b/Xamarin.Forms.Controls/GalleryPages/MapElementsGallery.xaml
@@ -13,6 +13,7 @@
                 <Picker.Items>
                     <x:String>Polyline</x:String>
                     <x:String>Polygon</x:String>
+                    <x:String>Circle</x:String>
                 </Picker.Items>
             </Picker>
             <Button Clicked="AddClicked"

diff --git a/Xamarin.Forms.Controls/GalleryPages/MapElementsGallery.xaml.cs b/Xamarin.Forms.Controls/GalleryPages/MapElementsGallery.xaml.cs
@@ -16,13 +16,15 @@ public partial class MapElementsGallery : ContentPage
 		enum SelectedElementType
 		{
 			Polyline,
-			Polygon
+			Polygon,
+			Circle
 		}
 
 		SelectedElementType _selectedType;
 
 		Polyline _polyline;
 		Polygon _polygon;
+		Circle _circle;
 
 		Random _random = new Random();
 
@@ -58,8 +60,17 @@ public MapElementsGallery()
 				}
 			};
 
+			_circle = new Circle
+			{
+				Center = new Position(42.352364, -71.067177),
+				Radius = Distance.FromMiles(100.0),
+				StrokeColor = Color.FromRgb(31, 174, 206),
+				FillColor = Color.FromRgba(31, 174, 206, 127)
+			};
+
 			Map.MapElements.Add(_polyline);
 			Map.MapElements.Add(_polygon);
+			Map.MapElements.Add(_circle);
 
 			ElementPicker.SelectedIndex = 0;
 		}
@@ -74,6 +85,16 @@ void MapClicked(object sender, MapClickedEventArgs e)
 				case SelectedElementType.Polygon:
 					_polygon.Geopath.Add(e.Position);
 					break;
+				case SelectedElementType.Circle:
+					if (_circle.Center == default(Position))
+					{
+						_circle.Center = e.Position;
+					}
+					else
+					{
+						_circle.Radius = Distance.BetweenPositions(_circle.Center, e.Position);
+					}
+					break;
 			}
 		}
 
@@ -92,6 +113,9 @@ void AddClicked(object sender, EventArgs e)
 				case SelectedElementType.Polygon:
 					Map.MapElements.Add(_polygon = new Polygon());
 					break;
+				case SelectedElementType.Circle:
+					Map.MapElements.Add(_circle = new Circle());
+					break;
 			}
 		}
 
@@ -114,6 +138,14 @@ void RemoveClicked(object sender, EventArgs e)
 					if (_polygon == null)
 						Map.MapElements.Add(_polygon = new Polygon());
 
+					break;
+				case SelectedElementType.Circle:
+					Map.MapElements.Remove(_circle);
+					_circle = Map.MapElements.OfType<Circle>().LastOrDefault();
+
+					if (_circle == null)
+						Map.MapElements.Add(_circle = new Circle());
+
 					break;
 			}
 		}
@@ -129,6 +161,9 @@ void ChangeColorClicked(object sender, EventArgs e)
 				case SelectedElementType.Polygon:
 					_polygon.StrokeColor = newColor;
 					break;
+				case SelectedElementType.Circle:
+					_circle.StrokeColor = newColor;
+					break;
 			}
 		}
 
@@ -143,6 +178,9 @@ void ChangeWidthClicked(object sender, EventArgs e)
 				case SelectedElementType.Polygon:
 					_polygon.StrokeWidth = newWidth;
 					break;
+				case SelectedElementType.Circle:
+					_circle.StrokeWidth = newWidth;
+					break;
 			}
 		}
 
@@ -154,6 +192,9 @@ void ChangeFillClicked(object sender, EventArgs e)
 				case SelectedElementType.Polygon:
 					_polygon.FillColor = newColor;
 					break;
+				case SelectedElementType.Circle:
+					_circle.FillColor = newColor;
+					break;
 			}
 		}
 	}

diff --git a/Xamarin.Forms.Core.UnitTests/DistanceTests.cs b/Xamarin.Forms.Core.UnitTests/DistanceTests.cs
@@ -58,6 +58,21 @@ public void ConstructFromMiles()
 			Assert.True(Math.Abs(distance.Kilometers - 6378.09999805) < EPSILON_FOR_LARGE_MILES_TO_KM);
 		}
 
+		[Test]
+		public void ConstructFromPositions()
+		{
+			const double EPSILON = 0.001;
+
+			Position position1 = new Position(37.403992, -122.034988);
+			Position position2 = new Position(37.776691, -122.416534);
+
+			Distance distance = Distance.BetweenPositions(position1, position2);
+
+			Assert.True(Math.Abs(distance.Meters - 53363.08) < EPSILON);
+			Assert.True(Math.Abs(distance.Kilometers - 53.36308) < EPSILON);
+			Assert.True(Math.Abs(distance.Miles - 33.15828) < EPSILON);
+		}
+
 		[Test]
 		public void EqualityOp([Range(5, 9)] double x, [Range(5, 9)] double y)
 		{