SceneDrawHelper.cs

using Esri.ArcGISRuntime.UI;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Symbology;
using System;
using System.Linq;
using System.Threading.Tasks;
using Esri.ArcGISRuntime.UI.Controls;

#if NETFX_CORE
using Windows.UI;
#else
using System.Windows.Media;
#endif

namespace SceneEditingDemo.Helpers
{
    /// <summary>
    /// Utility class that provides helper methods for drawing geometries on the <see cref="SceneView"/>.
    /// <see cref="SceneEditHelper"/> class provides simplified interface for creating and editing geometries.
    /// </summary>
	public class SceneDrawHelper
	{
		#region Default draw symbols
		//Symbol used by DrawPointAsync while moving the mouse
		private static MarkerSymbol DefaultMarkerSymbol = new SimpleMarkerSymbol() { Color = System.Drawing.Color.Blue };

		//Symbol used by DrawPolylineAsync	
		private static LineSymbol DefaultLineSymbol = new SimpleLineSymbol()
		{
			Width = 2,
			Color = System.Drawing.Color.FromArgb(150, 0, 0, 255)
		};

		//Symbol used by DrawPolygonAsync
		private static FillSymbol DefaultFillSymbol = new SimpleFillSymbol()
		{
			Outline = new SimpleLineSymbol() { Width = 2, Color = System.Drawing.Color.Black },
			Color = System.Drawing.Color.FromArgb(100, 0, 0, 255)
		};

		//Line Symbol used to show line between last added vertex and current mouse location
		private static LineSymbol DefaultLineMoveSymbol = new SimpleLineSymbol()
		{
			Width = 5,
			Color = System.Drawing.Color.FromArgb(100, 127, 127, 127),
			Style = SimpleLineSymbolStyle.Dot
		};
		#endregion Default draw symbols

		#region public draw operations
		public static async Task<MapPoint> DrawPointAsync(SceneView sceneView, System.Threading.CancellationToken cancellationToken)
		{
			var tcs = new TaskCompletionSource<MapPoint>();
			var sketchlayer = CreateSketchLayer(sceneView);
			sketchlayer.Opacity = .5;
			Graphic pointGraphic = null;
			Action cleanupEvents = SetUpHandlers(sceneView,
				(p) => //On mouse move move graphic around
				{
					if (p != null)
					{
						if (pointGraphic == null)
						{
							pointGraphic = new Graphic(p, DefaultMarkerSymbol);
							sketchlayer.Graphics.Add(pointGraphic);
						}
						else pointGraphic.Geometry = p;
					}
				},
				(p) => //View tapped - completes task and returns point
				{
					tcs.SetResult(p);
				}
				, null);
			Action cleanup = () =>
			{
				cleanupEvents();
				sceneView.GraphicsOverlays.Remove(sketchlayer);
			};
			cancellationToken.Register(() => tcs.SetCanceled());

			MapPoint result = null;
			try
			{
				result = await tcs.Task;
			}
			finally
			{
				cleanup();
			}
			return result;
		}

		public static async Task<Polyline> DrawPolylineAsync(SceneView sceneView, System.Threading.CancellationToken cancellationToken)
		{
			var tcs = new TaskCompletionSource<Polyline>();
			PolylineBuilder polylineBuilder = new PolylineBuilder(sceneView.SpatialReference);
			polylineBuilder.AddPart(new MapPoint[] { });
			var sketchlayer = CreateSketchLayer(sceneView);
			Graphic lineGraphic = new Graphic() { Symbol = DefaultLineSymbol };
			Graphic lineMoveGraphic = new Graphic() { Symbol = DefaultLineMoveSymbol };
			sketchlayer.Graphics.AddRange(new Graphic[] { lineGraphic, lineMoveGraphic });
			Action cleanupEvents = SetUpHandlers(sceneView,
				(p) => //On mouse move, move completion line around
				{
					if (p != null && polylineBuilder.Parts.Count > 0 && polylineBuilder.Parts[0].Count > 0)
					{
						lineMoveGraphic.Geometry = new Polyline(new MapPoint[] { polylineBuilder.Parts[0].Last().EndPoint, p });
					}
				},
				(p) => //On tap add a vertex
				{
					if (p != null)
					{
						polylineBuilder.AddPoint(p);
						if (polylineBuilder.Parts.Count > 0 && polylineBuilder.Parts[0].Count >= 1)
							lineGraphic.Geometry = polylineBuilder.ToGeometry();
					}
				},
				(p) => //View tapped - completes task and returns point
				{
					tcs.SetResult(polylineBuilder.ToGeometry());
				});
			Action cleanup = () =>
			{
				cleanupEvents();
				sceneView.GraphicsOverlays.Remove(sketchlayer);
			};
			cancellationToken.Register(() => tcs.SetCanceled());

			Polyline result = null;
			try
			{
				result = await tcs.Task;
			}
			finally
			{
				cleanup();
			}
			return result;
		}

		public static async Task<Polygon> DrawPolygonAsync(SceneView sceneView, System.Threading.CancellationToken cancellationToken)
		{
			var tcs = new TaskCompletionSource<Polygon>();
			PolygonBuilder polygonBuilder = new PolygonBuilder(sceneView.SpatialReference);
			polygonBuilder.AddPart(new MapPoint[] { });
			var sketchlayer = CreateSketchLayer(sceneView);
			Graphic polygonGraphic = new Graphic() { Symbol = DefaultFillSymbol };
			Graphic lineMoveGraphic = new Graphic() { Symbol = DefaultLineMoveSymbol };
			sketchlayer.Graphics.AddRange(new Graphic[] { polygonGraphic, lineMoveGraphic });
			Action cleanupEvents = SetUpHandlers(sceneView,
				(p) => //On mouse move move completion line around
				{
					if (p != null && polygonBuilder.Parts.Count > 0 && polygonBuilder.Parts[0].Count > 0)
					{
						lineMoveGraphic.Geometry = new Polyline(new MapPoint[] 
							{
								 polygonBuilder.Parts[0].Last().EndPoint, 
								 p, 
								 polygonBuilder.Parts[0].First().StartPoint
							});
					}
				},
				(p) => //On tap add a vertex
				{
					if (p != null)
					{
						polygonBuilder.AddPoint(p);
						if (polygonBuilder.Parts.Count > 0 && polygonBuilder.Parts[0].Count > 0)
						{
							polygonGraphic.Geometry = polygonBuilder.ToGeometry();
							lineMoveGraphic.Geometry = null;
						}
					}
				},
				(p) => //View tapped - completes task and returns point
				{
					tcs.SetResult(polygonBuilder.ToGeometry());
				});
			Action cleanup = () =>
			{
				cleanupEvents();
				sceneView.GraphicsOverlays.Remove(sketchlayer);
			};
			cancellationToken.Register(() => tcs.SetCanceled());

			Polygon result = null;
			try
			{
				result = await tcs.Task;
			}
			finally
			{
				cleanup();
			}

			return result;
		}
		#endregion public draw operations

		#region Private utility methods
		/// <summary>
		/// Helper for adding mouse events
		/// </summary>
		/// <param name="view">The view to listen for events on.</param>
		/// <param name="onMove">Action when the mouse moves.</param>
		/// <param name="onTapped">Action when the view is tapped.</param>
		/// <param name="onDoubleTapped">Action when the view is double tapped.</param>
		/// <returns>An Action that cleans up all the event handlers.</returns>
		private static Action SetUpHandlers(SceneView view, Action<MapPoint> onMove, Action<MapPoint> onTapped, Action<MapPoint> onDoubleTapped)
		{
#if NETFX_CORE
			Windows.UI.Xaml.Input.PointerEventHandler movehandler = null;
#else
			System.Windows.Input.MouseEventHandler movehandler = null;
#endif

			if (onMove != null)
			{
#if NETFX_CORE
				movehandler = (s, e) => onMove(view.ScreenToBaseSurface(e.GetCurrentPoint(view).Position));
				view.PointerMoved += movehandler;
#else
				movehandler = (s, e) => onMove(view.ScreenToBaseSurface(e.GetPosition(view)));
				view.MouseMove += movehandler;
#endif
			}
			EventHandler<GeoViewInputEventArgs> tappedHandler = null;
			if (onTapped != null)
			{
				tappedHandler = (s, e) => onTapped(e.Location);
				view.GeoViewTapped += tappedHandler;
			}
			EventHandler<GeoViewInputEventArgs> doubletappedHandler = null;
			if (onDoubleTapped != null)
			{
				doubletappedHandler = (s, e) => { e.Handled = true; onDoubleTapped(e.Location); };
				view.GeoViewDoubleTapped += doubletappedHandler;
			}
			Action cleanup = () =>
			{
				if (movehandler != null)
#if NETFX_CORE
					view.PointerMoved -= movehandler;
#else
					view.MouseMove -= movehandler;
#endif
				if (tappedHandler != null) view.GeoViewTapped -= tappedHandler;
				if (doubletappedHandler != null) view.GeoViewDoubleTapped -= doubletappedHandler;
			};
			return cleanup;
		}

		private static GraphicsOverlay CreateSketchLayer(GeoView scene)
		{
			GraphicsOverlay go = new GraphicsOverlay();
			scene.GraphicsOverlays.Add(go);
			return go;
		}
		#endregion Private utility methods
	}
}