using (GraphicsPath _Path = new GraphicsPath())
{
    _Path.AddLine(mouseDownX, mouseDownY, mouseUpdX, mouseUpY);
    // Draw the shadow.
    mygraphics.TranslateTransform(3, 3); //displacement
    using (Pen _Pen = new Pen(Color.FromArgb(30, 0, 0, 0), hPen.Width))
    {
         _Pen.CustomStartCap = adjustableArrowCap_0;
         mygraphics.DrawPath(_Pen, _Path);
    }
    mygraphics.ResetTransform();
}
mygraphics.DrawLine(hPen, mouseDownX, mouseDownY, mouseUpdX, mouseUpY);