using System;  
 using System.Collections.Generic;  
 using System.Linq;  
 using System.Windows.Forms;  
 
 namespace SnapToLayer  
 {  
     static class Program  
     {  
         /// <summary>  
         /// The main entry point for the application.  
         /// </summary>  
         [STAThread]  
         static void Main()  
         {  
             Application.EnableVisualStyles();  
             Application.SetCompatibleTextRenderingDefault(false);  
             Application.Run(new TestForm());  
         }  
     }  
 }  
 

using System.Collections.ObjectModel;  
 using ThinkGeo.MapSuite.Core;  
 using ThinkGeo.MapSuite.DesktopEdition;  
 
 namespace SnapToLayer  
 {  
     public enum ToleranceCoordinates { World, Screen };  
     class SnapToLayerEditInteractiveOverlay : EditInteractiveOverlay  
     {  
         private PointStyle controlPointStyle;  
         private PointStyle draggedControlPointStyle;  
         private InMemoryFeatureLayer toSnapInMemoryFeatureLayer;  
         private float tolerance;  
         //private int tolerancePixel;  
         private DistanceUnit toleranceUnit;  
         private GeographyUnit geographyUnit;  
 
         private RectangleShape currentWorldExtent;  
         private float mapWidth;  
         private float mapHeight;  
         private ToleranceCoordinates toleranceType;  
 
 
 
         //Property for the non dragged control point style.  
         public PointStyle ControlPointStyle  
         {  
             get { return controlPointStyle; }  
             set { controlPointStyle = value; }  
         }  
 
         //Property for the dragged control point style.  
         public PointStyle DraggedControlPointStyle  
         {  
             get { return draggedControlPointStyle; }  
             set { draggedControlPointStyle = value; }  
         }  
 
         //InMemoryFeatureLayer for the layer to be snapped to.  
         public InMemoryFeatureLayer ToSnapInMemoryFeatureLayer  
         {  
             get { return toSnapInMemoryFeatureLayer; }  
             set { toSnapInMemoryFeatureLayer = value; }  
         }  
 
         public ToleranceCoordinates ToleranceType  
         {  
             get { return toleranceType; }  
             set { toleranceType = value; }  
         }  
 
         public float Tolerance  
         {  
             get { return tolerance; }  
             set { tolerance = value; }  
         }  
 
         public DistanceUnit ToleranceUnit  
         {  
             get { return toleranceUnit; }  
             set { toleranceUnit = value; }  
         }  
 
         //Overrides the MoveVertexCore to have the logic to check if the dragged control point is within tolerance.  
         protected override Feature MoveVertexCore(Feature sourceFeature, PointShape sourceControlPoint, PointShape targetControlPoint)  
         {  
             VertexMovingEditInteractiveOverlayEventArgs vertexMovingEditInteractiveOverlayEventArgs = new VertexMovingEditInteractiveOverlayEventArgs(false, sourceFeature, new Vertex(targetControlPoint));  
 
             PointShape snapPointShape = null;  
             if (toleranceType == ToleranceCoordinates.Screen)  
             {  
                  snapPointShape = FindNearestSnappingPointPixel(targetControlPoint);  
             }  
             else  
             {  
                 snapPointShape = FindNearestSnappingPoint(targetControlPoint);  
             }  
 
             if (snapPointShape != null)  
             {  
                 vertexMovingEditInteractiveOverlayEventArgs.MovingVertex = new Vertex(snapPointShape);  
             }  
 
             return base.MoveVertexCore(sourceFeature, sourceControlPoint, new PointShape(vertexMovingEditInteractiveOverlayEventArgs.MovingVertex));  
         }  
 
         //Function to find if dragged control point is within the tolerance of a vertex of layer in screen (pixels) coordinates.  
         private PointShape FindNearestSnappingPointPixel(PointShape targetPointShape)  
         {  
             toSnapInMemoryFeatureLayer.Open();  
             Collection<Feature> toSnapInMemoryFeatures = toSnapInMemoryFeatureLayer.FeatureSource.GetFeaturesNearestTo(targetPointShape, GeographyUnit.Meter, 1, ReturningColumnsType.AllColumns);  
             toSnapInMemoryFeatureLayer.Close();  
 
             if (toSnapInMemoryFeatures.Count == 1)  
             {  
                 PolygonShape polygonShape = (PolygonShape)toSnapInMemoryFeatures[0].GetShape();  
 
                 foreach (Vertex vertex in polygonShape.OuterRing.Vertices)  
                 {  
                     PointShape toSnapPointShape = new PointShape(vertex);  
                     float screenDistance = ExtentHelper.GetScreenDistanceBetweenTwoWorldPoints(currentWorldExtent, toSnapPointShape, targetPointShape, mapWidth, mapHeight);  
 
                     if (screenDistance <= tolerance)  
                     {  
                         return new PointShape(toSnapPointShape.X, toSnapPointShape.Y);  
                     }  
                  }  
             }  
             return null;  
         }  
 
         //Function to find if dragged control point is within the tolerance of a vertex of layer in world coordinates.  
         private PointShape FindNearestSnappingPoint(PointShape targetPointShape)  
         {  
             toSnapInMemoryFeatureLayer.Open();  
             Collection<Feature> toSnapInMemoryFeatures = toSnapInMemoryFeatureLayer.FeatureSource.GetFeaturesNearestTo(targetPointShape, GeographyUnit.Meter, 1, ReturningColumnsType.AllColumns);  
             toSnapInMemoryFeatureLayer.Close();  
 
             if (toSnapInMemoryFeatures.Count == 1)  
             {  
                 PolygonShape polygonShape = (PolygonShape)toSnapInMemoryFeatures[0].GetShape();  
 
                 foreach (Vertex vertex in polygonShape.OuterRing.Vertices)  
                 {  
                     PointShape toSnapPointShape = new PointShape(vertex);  
                     double Distance = toSnapPointShape.GetDistanceTo(targetPointShape, geographyUnit, toleranceUnit);  
 
                     if (Distance <= tolerance)  
                     {  
                         return new PointShape(toSnapPointShape.X, toSnapPointShape.Y);  
                     }  
                 }  
             }  
             return null;  
         }  
 
         //Overrides the DrawCore function to draw the Edit Layers, the vertices and tolerance ellipses of layer to snap to,  
         //and the control points.  
         protected override void DrawCore(GeoCanvas canvas)  
         {  
             //Sets the geography Unit used in FindNearestSnappingPoint function  
             geographyUnit = canvas.MapUnit;  
             currentWorldExtent = canvas.CurrentWorldExtent;  
             mapWidth = canvas.Width;  
             mapHeight = canvas.Height;  
 
             //Draws the Edit Shapes as default.  
             Collection<SimpleCandidate> labelsInAllLayers = new Collection<SimpleCandidate>();  
             EditShapesLayer.Open();  
             EditShapesLayer.Draw(canvas, labelsInAllLayers);  
             canvas.Flush();  
 
             //Draw the vertices and tolerance ellipses of layer to snap to.  
             toSnapInMemoryFeatureLayer.Open();  
             Collection<Feature> toSnapPoints = toSnapInMemoryFeatureLayer.FeatureSource.GetAllFeatures(ReturningColumnsType.AllColumns);  
             toSnapInMemoryFeatureLayer.Close();  
             foreach (Feature feature in toSnapPoints)  
             {  
                 PolygonShape polygonShape = (PolygonShape)feature.GetShape();  
 
                 foreach (Vertex vertex in polygonShape.OuterRing.Vertices)  
                 {  
                     //Draws the vertex.  
                     PointShape pointShape = new PointShape(vertex);  
                     canvas.DrawEllipse(pointShape, 5, 5, new GeoSolidBrush(GeoColor.StandardColors.Black), DrawingLevel.LevelOne);  
 
                     //Draws the tolerance ellipse.  
                     if (toleranceType == ToleranceCoordinates.Screen)  
                     {  
                         ScreenPointF screenPointF = ExtentHelper.ToScreenCoordinate(canvas.CurrentWorldExtent, pointShape, canvas.Width, canvas.Height);  
                         canvas.DrawEllipse(screenPointF, tolerance * 2, tolerance * 2, new GeoPen(GeoColor.StandardColors.Black), new GeoSolidBrush(), DrawingLevel.LevelFour, 0, 0, PenBrushDrawingOrder.PenFirst);  
                     }  
                     else  
                     {  
                         EllipseShape ellipseShape = new EllipseShape(pointShape, tolerance, canvas.MapUnit, toleranceUnit);  
                         canvas.DrawArea(ellipseShape, new GeoPen(GeoColor.StandardColors.Black), DrawingLevel.LevelOne);  
                     }  
                 }  
             }  
 
             //Draws the control points.  
             ExistingControlPointsLayer.Open();  
             Collection<Feature> controlPoints = ExistingControlPointsLayer.FeatureSource.GetAllFeatures(ReturningColumnsType.AllColumns);  
 
             //Loops thru the control points.  
             foreach (Feature feature in controlPoints)  
             {  
                 //Looks at the value of "state" to draw the control point as dragged or not.  
                 if (feature.ColumnValues["state"] != "selected")  
                 {  
                     Feature[] features = new Feature[1] { feature };  
                     controlPointStyle.Draw(features, canvas, labelsInAllLayers, labelsInAllLayers);  
                 }  
                 else  
                 {  
                     Feature[] features = new Feature[1] { feature };  
                     draggedControlPointStyle.Draw(features, canvas, labelsInAllLayers, labelsInAllLayers);  
                 }  
             }  
         }  
     }  
 }  
 

using System;  
 using System.IO;  
 using System.Windows.Forms;  
 using ThinkGeo.MapSuite.Core;  
 using ThinkGeo.MapSuite.DesktopEdition;  
 
 namespace  SnapToLayer  
 {  
     public partial class TestForm : Form  
     {  
         public TestForm()  
         {  
             InitializeComponent();  
         }  
 
         private void TestForm_Load(object sender, EventArgs e)  
         {  
             winformsMap1.MapUnit = GeographyUnit.DecimalDegree;  
             winformsMap1.CurrentExtent = new RectangleShape(-97.7591, 30.3126, -97.7317, 30.2964);  
             winformsMap1.BackgroundOverlay.BackgroundBrush = new GeoSolidBrush(GeoColor.FromArgb(255, 198, 255, 255));  
 
             //Displays the World Map Kit as a background.  
             ThinkGeo.MapSuite.DesktopEdition.WorldMapKitWmsDesktopOverlay worldMapKitDesktopOverlay = new ThinkGeo.MapSuite.DesktopEdition.WorldMapKitWmsDesktopOverlay();  
             winformsMap1.Overlays.Add(worldMapKitDesktopOverlay);  
 
             string fileName1 = @"..\..\data\polygon.txt";  
             StreamReader sr1 = new StreamReader(fileName1);  
 
             string fileName2 = @"..\..\data\line.txt";  
             StreamReader sr2 = new StreamReader(fileName2);  
 
             //SnapToLayerEditInteractiveOverlay to snap dragged control point to nearest vertex of layer if within tolerance.  
             SnapToLayerEditInteractiveOverlay snapToLayerEditInteractiveOverlay = new SnapToLayerEditInteractiveOverlay();  
 
             //inMemoryFeatureLayer used to be snapped to.  
             InMemoryFeatureLayer polygonInMemoryFeatureLayer = new InMemoryFeatureLayer();  
             polygonInMemoryFeatureLayer.ZoomLevelSet.ZoomLevel01.DefaultAreaStyle = AreaStyles.Park1;  
             polygonInMemoryFeatureLayer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;  
             polygonInMemoryFeatureLayer.InternalFeatures.Add("Polygon", new Feature(BaseShape.CreateShapeFromWellKnownData(sr1.ReadLine())));  
 
             LayerOverlay inMemoryOverlay = new LayerOverlay();  
             inMemoryOverlay.Layers.Add("InMemoryFeatureLayer", polygonInMemoryFeatureLayer);  
             winformsMap1.Overlays.Add("InMemoryOverlay", inMemoryOverlay);  
 
             snapToLayerEditInteractiveOverlay.EditShapesLayer.InternalFeatures.Add("MultiLine", new Feature(BaseShape.CreateShapeFromWellKnownData(sr2.ReadLine())));  
 
             //Sets the PointStyle for the non dragged control points.  
             snapToLayerEditInteractiveOverlay.ControlPointStyle = new PointStyle(PointSymbolType.Circle, new GeoSolidBrush(GeoColor.StandardColors.PaleGoldenrod), new GeoPen(GeoColor.StandardColors.Black), 8);  
             //Sets the PointStyle for the dragged control points.  
             snapToLayerEditInteractiveOverlay.DraggedControlPointStyle = new PointStyle(PointSymbolType.Circle, new GeoSolidBrush(GeoColor.StandardColors.Red), new GeoPen(GeoColor.StandardColors.Orange, 2), 10);  
 
             snapToLayerEditInteractiveOverlay.ToSnapInMemoryFeatureLayer = polygonInMemoryFeatureLayer;  
 
             //Example using Screen (Pixel) coordinates for tolerance.  
             snapToLayerEditInteractiveOverlay.ToleranceType = ToleranceCoordinates.Screen;  
             snapToLayerEditInteractiveOverlay.Tolerance = 25;  
 
             //Example using World coordinates for tolerance.  
             //snapToLayerEditInteractiveOverlay.ToleranceType = ToleranceCoordinates.World;  
             //snapToLayerEditInteractiveOverlay.Tolerance = 150;  
             //snapToLayerEditInteractiveOverlay.ToleranceUnit = DistanceUnit.Meter;  
 
             snapToLayerEditInteractiveOverlay.CalculateAllControlPoints();  
 
             winformsMap1.EditOverlay = snapToLayerEditInteractiveOverlay;  
 
             winformsMap1.Refresh();  
         }  
 
         private void winformsMap1_MouseMove(object sender, MouseEventArgs e)  
         {  
             //Displays the X and Y in screen coordinates.  
             statusStrip1.Items["toolStripStatusLabelScreen"].Text = "X:" + e.X + " Y:" + e.Y;  
 
             //Gets the PointShape in world coordinates from screen coordinates.  
             PointShape pointShape = ExtentHelper.ToWorldCoordinate(winformsMap1.CurrentExtent, new ScreenPointF(e.X, e.Y), winformsMap1.Width, winformsMap1.Height);  
 
             //Displays world coordinates.  
             statusStrip1.Items["toolStripStatusLabelWorld"].Text = "(world) X:" + Math.Round(pointShape.X, 4) + " Y:" + Math.Round(pointShape.Y, 4);  
         }  
 
         private void btnClose_Click(object sender, EventArgs e)  
         {  
             this.Close();  
         }  
     }  
 }