class LineRenderer : DynamicRenderer
{
    private Point firstPoint;
    private Pen pen = new Pen(new SolidColorBrush(Colors.Gray),1);

    public LineRenderer()
    {
        firstPoint = new Point(double.PositiveInfinity, double.PositiveInfinity);
    }

    protected override void OnStylusDown(RawStylusInput rawStylusInput)
    {
        firstPoint = new Point(rawStylusInput.GetStylusPoints().First().ToPoint().X, rawStylusInput.GetStylusPoints().First().ToPoint().Y);
        base.OnStylusDown(rawStylusInput);
    }

    protected override void OnDraw(DrawingContext drawingContext,
                                   StylusPointCollection stylusPoints,
                                   Geometry geometry, Brush fillBrush)
    {
        drawingContext.DrawLine(pen, firstPoint, stylusPoints.First().ToPoint());
    }

    protected override void OnStylusUp(RawStylusInput rawStylusInput)
    {
        firstPoint = new Point(double.PositiveInfinity, double.PositiveInfinity);
        base.OnStylusUp(rawStylusInput);
    }
}

protected override void OnDraw(DrawingContext drawingContext,
                               StylusPointCollection stylusPoints,
                               Geometry geometry, Brush fillBrush)
{
    drawingContext.DrawLine(pen, firstPoint, stylusPoints.First().ToPoint());
firstPoint = stylusPoints.First().ToPoint();
}

protected override void OnDraw(DrawingContext drawingContext,
                               StylusPointCollection stylusPoints,
                               Geometry geometry, Brush fillBrush)
        {
            if (!_isManipulating)
            {
                _isManipulating = true;
                StylusDevice currentStylus = Stylus.CurrentStylusDevice;
                this.Reset(currentStylus, stylusPoints);
            }
            _isManipulating = false;

            var pen = new Pen(brush, 2);
            drawingContext.DrawLine(pen, startPoint,stylusPoints.First().ToPoint());
       }


protected override void OnStylusDown(RawStylusInput rawStylusInput)
        {
            StylusPointCollection y = rawStylusInput.GetStylusPoints();
            startPoint = (Point)y.First();

            // Allocate memory to store the previous point to draw from.
            prevPoint = new Point(double.NegativeInfinity, double.NegativeInfinity);
            base.OnStylusDown(rawStylusInput);
        }