private void btScan_Click(object sender, EventArgs e)
{
if (polist.SelectedItems.Count > 0)
{
ScanLine scan = new ScanLine(polys[polist.SelectedIndex]);
img = scan.Fill(Color.DarkGreen, (Bitmap)img);
picBox.Image = img;
ScanLine scanVP = new ScanLine(VPs[polist.SelectedIndex]);
VP = scanVP.Fill(Color.DarkGreen, VP);
ViewPort.Image = VP;
}
}