MissionPlanner.GMapMarkerRover.OnRender C# (CSharp) Method

        public override void OnRender(Graphics g)
        {
            Matrix temp = g.Transform;
            g.TranslateTransform(LocalPosition.X, LocalPosition.Y);

            g.RotateTransform(-Overlay.Control.Bearing);

            int length = 500;
            // anti NaN
            try
            {
                g.DrawLine(new Pen(Color.Red, 2), 0.0f, 0.0f, (float) Math.Cos((heading - 90)*deg2rad)*length,
                    (float) Math.Sin((heading - 90)*deg2rad)*length);
            }
            catch
            {
            }
            g.DrawLine(new Pen(Color.Green, 2), 0.0f, 0.0f, (float) Math.Cos((nav_bearing - 90)*deg2rad)*length,
                (float) Math.Sin((nav_bearing - 90)*deg2rad)*length);
            g.DrawLine(new Pen(Color.Black, 2), 0.0f, 0.0f, (float) Math.Cos((cog - 90)*deg2rad)*length,
                (float) Math.Sin((cog - 90)*deg2rad)*length);
            g.DrawLine(new Pen(Color.Orange, 2), 0.0f, 0.0f, (float) Math.Cos((target - 90)*deg2rad)*length,
                (float) Math.Sin((target - 90)*deg2rad)*length);
            // anti NaN

            try
            {
                g.RotateTransform(heading);
            }
            catch
            {
            }
            g.DrawImageUnscaled(global::MissionPlanner.Properties.Resources.rover,
                global::MissionPlanner.Properties.Resources.rover.Width/-2,
                global::MissionPlanner.Properties.Resources.rover.Height/-2);

            g.Transform = temp;
        }
    }