Article	60001694
Type	HowTo
Product	Engine
Version	6
Date Added	5/10/2012
Submitted by	Kerry Francis
Keywords

Subject

How can I rotate the vertices in a polyline around a certain point

Summary

How (through code) can I rotate the some vertices in a polyline around a certain point keeping some other vertices the same ?

Solution

Try a code like:

        private void MyButton_Click(object sender, EventArgs e)
        {
            vdDocument doc = vdFramedControl1.BaseControl.ActiveDocument; doc.New();
            Vertexes vrts = new Vertexes();
            vrts.Add(1,1,0,0);vrts.Add(1,4,0,0);vrts.Add(4,4,0,0);vrts.Add(5,3,0,0);
            vdPolyline pl = new vdPolyline(doc, vrts);
            doc.Model.Entities.AddItem(pl);
            pl.Invalidate();
            //--------------- created the polyline ---------
           
            
            // rotate it for 45 degrees anti-clockwise around vertex[1]
            
            Vertexes orig_vert = new Vertexes(pl.VertexList);//get the vertex list of the polyline that will be changed
            gPoint pt1 = new gPoint(orig_vert[1] as gPoint);
       
            // Vertexes from Item 2 and above will change
            Vertexes keep = new Vertexes();
            keep.Add(new Vertex(orig_vert[0]));
            keep.Add(new Vertex(orig_vert[1]));

            double orig_angle = pt1.GetAngle( orig_vert[2] as gPoint); // new angle
            orig_angle += VectorDraw.Geometry.Globals.DegreesToRadians(45.0d);

            Matrix mat = new Matrix();
            mat.TranslateMatrix(-1.0d * pt1);
            mat.RotateZMatrix(orig_angle);
            mat.TranslateMatrix(pt1);
            mat.Transform(orig_vert); // this will produce the new vertexes

            for (int i = 0; i < 2; i++)
            {
                orig_vert[i] = keep[i]; // restore the vertexes that didn't changed
            }

            pl.VertexList = orig_vert;
            pl.Update();
            pl.Invalidate();

        }