Convert this Polygon to Polyline

Question

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Drawing.Drawing2D;

namespace howto_draw_polygons

{

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

}

// Each polygon is represented by a List<Point>.

private List<List<Point>> Polygons = new List<List<Point>>();

// Points for the new polygon.

private List<Point> NewPolygon = null;

// The current mouse position while drawing a new polygon.

private Point NewPoint;

// Start or continue drawing a new polygon.

private void picCanvas_MouseDown(object sender, MouseEventArgs e)

{

// See if we are already drawing a polygon.

if (NewPolygon != null)

{

// We are already drawing a polygon.

// If it's the right mouse button, finish this polygon.

if (e.Button == MouseButtons.Right)

{

// Finish this polygon.

if (NewPolygon.Count > 2) Polygons.Add(NewPolygon);

NewPolygon = null;

}

else

{

// Add a point to this polygon.

if (NewPolygon[NewPolygon.Count - 1] != e.Location)

{

NewPolygon.Add(e.Location);

}

}

}

else

{

// Start a new polygon.

NewPolygon = new List<Point>();

NewPoint = e.Location;

NewPolygon.Add(e.Location);

}

// Redraw.

picCanvas.Invalidate();

}

// Move the next point in the new polygon.

private void picCanvas_MouseMove(object sender, MouseEventArgs e)

{

if (NewPolygon == null) return;

NewPoint = e.Location;

picCanvas.Invalidate();

}

// Redraw old polygons in blue. Draw the new polygon in green.

// Draw the final segment dashed.

private void picCanvas_Paint(object sender, PaintEventArgs e)

{

e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;

e.Graphics.Clear(picCanvas.BackColor);

// Draw the old polygons.

foreach (List<Point> polygon in Polygons)

{

e.Graphics.FillPolygon(Brushes.White, polygon.ToArray());

e.Graphics.DrawPolygon(Pens.Blue, polygon.ToArray());

}

// Draw the new polygon.

if (NewPolygon != null)

{

// Draw the new polygon.

if (NewPolygon.Count > 1)

{

e.Graphics.DrawLines(Pens.Green, NewPolygon.ToArray());

}

// Draw the newest edge.

if (NewPolygon.Count > 0)

{

using (Pen dashed_pen = new Pen(Color.Green))

{

dashed_pen.DashPattern = new float[] { 3, 3 };

e.Graphics.DrawLine(dashed_pen,

NewPolygon[NewPolygon.Count - 1],

NewPoint);

}

}

}

}

}

}