title: Drag & Drop modyfiing polygon shape by moving vertices in C#
body: <p><br/>
  I have to do application for tilling in C#. The tiles will have some shape and my app should be able to modify the shape. I will have a some shape - polygon, made from vertices. I will have for example field of 16 vertices, then I draw the polygon. 
  What I need to know <strong>how can I move with the the vertice using drag and drop.</strong> I will also have to recount other vertices in order to fit one tile to next tile, but it's just some math. </p>
  
  <p>To conclude:
  I have polygon defined 16 vertices in field of Vertices, I move (with mouse) with one vertice, recount the coordinates of ohter vertices and draw new polygon. My problem is moving (probably using drag &amp; drop) with one vertice from filed of vertices.</p>
  
  <p>This is what part of my previous code without drag &amp; drop - just for idea what tools I'm using for drawing one tile:</p>
  
  <pre><code> private Bitmap canvasBitmap; //canvas for drawing
   private Graphics g; // enter to graphics tool  
  
              Bitmap b = (Bitmap)Bitmap.FromFile("obr.bmp");
              TextureBrush brush = new TextureBrush(b);
              Pen pen = new Pen(Color.Black, 1);
  
              hexaVertices[0] = new PointF(-40 + 40, 0 + 30);
              hexaVertices[1] = new PointF(-20 + 40, 30 + 30);
              hexaVertices[2] = new PointF(20 + 40, 30 + 30);
              hexaVertices[3] = new PointF(40 + 40, 0 + 30);
              hexaVertices[4] = new PointF(20 + 40, -30 + 30);
              hexaVertices[5] = new PointF(-20 + 40, -30 + 30);
  
   g.FillPolygon(brush, hexaVertices);
   g.DrawPolygon(pen, hexaVertices);
  </code></pre>
  
  <p>Thx for advices.</p>