Hi Irvin,
Provided code is working with polygons
that has a straight segments only
My bad, have forgot you use vb.net, I wrote
code completely on C#, ugh 🙂
I haven't a time to translate it on VB.Net
Tryit by yourself
Hope that helps,
Oleg
~'J'~
/// <summary>
/// Point-In-Polygon Algorithm © 1998,2006,2007 Darel Rex Finley
/// working with straight segments ony!
/// http://alienryderflex.com/polygon/
/// The function will return YES if the point x,y is inside the polygon, or
/// NO if it is not. If the point is exactly on the edge of the polygon,
/// then the function may return YES or NO.
/// Note that division by zero is avoided because the division is protected
/// by the "if" clause which surrounds it.
/// </summary>
/// <param name="polySides"></param>
/// <param name="polyX"></param>
/// <param name="polyY"></param>
/// <param name="p"></param>
/// <returns></returns>
public static bool pointInPolygon(int polySides, double[] polyX, double[] polyY, Point2d p)
{
int i, j = polySides - 1;
bool oddNodes = false;
double x = p.X;
double y = p.Y;
for (i = 0; i < polySides; i++)
{
if ((polyY[i] < y && polyY[j] >= y) || (polyY[j] < y && polyY[i] >= y))
{
if (polyX[i] + (y - polyY[i]) / (polyY[j] - polyY[i]) * (polyX[j] - polyX[i]) < x)
{
oddNodes = !oddNodes;
}
}
j = i;
}
return oddNodes;
}
/// <summary>
/// by Gilles Chanteau ()2010
/// </summary>
/// <param name="idCol"></param>
private static void ZoomObjects(ObjectIdCollection idCol)
{
Document doc = Application.DocumentManager.MdiActiveDocument;
Database db = doc.Database;
Editor ed = doc.Editor;
using (Transaction tr = db.TransactionManager.StartTransaction())
using (ViewTableRecord view = ed.GetCurrentView())
{
Matrix3d WCS2DCS = Matrix3d.PlaneToWorld(view.ViewDirection);
WCS2DCS = Matrix3d.Displacement(view.Target - Point3d.Origin) * WCS2DCS;
WCS2DCS = Matrix3d.Rotation(-view.ViewTwist, view.ViewDirection, view.Target) * WCS2DCS;
WCS2DCS = WCS2DCS.Inverse();
Entity ent = (Entity)tr.GetObject(idCol[0], OpenMode.ForRead);
Extents3d ext = ent.GeometricExtents;
for (int i = 1; i < idCol.Count; i++)
{
ent = (Entity)tr.GetObject(idCol[i], OpenMode.ForRead);
Extents3d tmp = ent.GeometricExtents;
ext.AddExtents(tmp);
}
ext.TransformBy(WCS2DCS);
view.Width = ext.MaxPoint.X - ext.MinPoint.X;
view.Height = ext.MaxPoint.Y - ext.MinPoint.Y;
view.CenterPoint = new Point2d((ext.MaxPoint.X + ext.MinPoint.X) / 2.0, (ext.MaxPoint.Y + ext.MinPoint.Y) / 2.0);
ed.SetCurrentView(view);
tr.Commit();
}
}
/// <summary>
/// test for multiple shapes inside a straight-segmented polygon (partially borrowed from Kean Walmsley)
/// </summary>
[CommandMethod("MultiPoly", CommandFlags.UsePickSet | CommandFlags.Redraw | CommandFlags.Modal)]
public static void testIfShapeInside()
{
Database db = HostApplicationServices.WorkingDatabase;
Document doc = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument;
Editor ed = doc.Editor;
DocumentLock docloc = doc.LockDocument();
using(docloc)
{
Transaction tr = db.TransactionManager.StartTransaction();
using (tr)
{
try
{
PromptEntityOptions peo = new PromptEntityOptions("\nSelect a boundary polygon >>");
peo.SetRejectMessage("\nSelect Polyline only >>");
peo.AddAllowedClass(typeof(Polyline), false);
PromptEntityResult res;
res = ed.GetEntity(peo);
if (res.Status != PromptStatus.OK)
return;
Entity ent = (Entity)tr.GetObject(res.ObjectId, OpenMode.ForRead);
if (ent == null)
return;
ObjectId chkId = ent.ObjectId;
ZoomObjects(new ObjectIdCollection() { chkId });
Point3dCollection pts = new Point3dCollection();
Polyline poly = (Polyline)ent as Polyline;
if (poly != null)
{
int num = poly.NumberOfVertices;
double[] polyX = new double[num];
double[] polyY = new double[num];
for (int i = 0; i < num; i++)
{
Point2d p = poly.GetPoint2dAt(i);
polyX[i] = p.X; polyY[i] = p.Y;
pts.Add(poly.GetPointAtParameter((double)i));
}
TypedValue[] filList = new TypedValue[2] {new TypedValue((int)DxfCode.Start, "LWPOLYLINE"),new TypedValue(70, 1) };
SelectionFilter filter = new SelectionFilter(filList);
PromptSelectionResult sres = ed.SelectCrossingPolygon(pts, filter);
// Do nothing if selection is unsuccessful
if (sres.Status != PromptStatus.OK)
return;
SelectionSet selSet = sres.Value;
ObjectId[] ids = selSet.GetObjectIds();
for (int i = 0; i < ids.Length; i++)
{
if ((ObjectId)ids[i] != chkId)//exclude a boundary from selection
{
poly = (Polyline)tr.GetObject(ids[i], OpenMode.ForRead);
int vnum = poly.NumberOfVertices;
bool isInside = true;
for (int j = 0; j < vnum; j++)
{
Point2d p = poly.GetPoint2dAt(j);
//
isInside = pointInPolygon(num, polyX, polyY, p);
if (!isInside)
{
poly.UpgradeOpen();
poly.ColorIndex = 3;
poly.DowngradeOpen();
break;
}
}
}
}//
}
tr.Commit();
}
catch (System.Exception ex)
{
ed.WriteMessage("{0}\n{1}", ex.Message, ex.StackTrace);
}
}//tr
}
}
/// <summary>
/// test is point inside a straight-segmented polygon(partially borrowed from Kean Walmsley)
/// </summary>
[CommandMethod("SinglePoint", CommandFlags.UsePickSet | CommandFlags.Modal)]
public static void testInside()
{
Document doc = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument;
Database db = doc.Database;
Editor ed = doc.Editor;
using (Transaction tr = db.TransactionManager.StartTransaction())
{
PromptPointOptions prOpt = new PromptPointOptions("\nSpecify a point: ");
PromptPointResult es = ed.GetPoint(prOpt);
if (es.Status != PromptStatus.OK)
{
if (es.Status == PromptStatus.Cancel)
{
ed.WriteMessage("\nInterrupted by user. Exit.."); return;
}
else
{
ed.WriteMessage("\nError on specifying a point.Exit..."); return;
}
}
Point2d pt = new Point2d(es.Value.X, es.Value.Y);
PromptEntityOptions peo = new PromptEntityOptions("\nSelect a bounds polygon >>");
peo.SetRejectMessage("\nSelect Polyline only >>");
peo.AddAllowedClass(typeof(Polyline),false);
PromptEntityResult res;
res = ed.GetEntity(peo);
if (res.Status != PromptStatus.OK)
return;
Entity ent = (Entity)tr.GetObject(res.ObjectId, OpenMode.ForRead);
if (ent == null)
return;
Polyline poly = (Polyline)ent as Polyline;
if (poly != null)
{
int num = poly.NumberOfVertices;
double[] polyX = new double[num];
double[] polyY = new double[num];
for (int i = 0; i < num; i++)
{
Point2d p = poly.GetPoint2dAt(i);
polyX[i] = p.X; polyY[i] = p.Y;
}
bool isInside = pointInPolygon(num, polyX, polyY, pt);
ed.WriteMessage("\nIs point inside?\t{0}", isInside);
}
tr.Commit();
}
}
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