Free draw view for Xamarin Android

FreeDrawView.cs

using Android.Content;
using Android.Graphics;
using Android.Util;
using Android.Views;

namespace Droid
{
    public class FreeDrawView : View
    {
        Path _drawPath;
        Paint _drawPaint;
        Paint _canvasPaint;
        Canvas _drawCanvas;
        Bitmap _canvasBitmap;
        Color _currentLineColor;
        float _penWidth;

        public Bitmap Image
        {
            get
            {
                return GetDrawingCache(false);
            }
        }

        public FreeDrawView(Context context)
            : base(context)
        {
            Init();
        }

        public FreeDrawView(Context context, IAttributeSet attrs)
            : base(context, attrs)
        {
            Init();
        }

        public FreeDrawView(Context context, IAttributeSet attrs, int defStyle)
            : base(context, attrs, defStyle)
        {
            Init();
        }

        void Init()
        {
            _currentLineColor = Color.Black;
            _penWidth = 8.0f;

            _drawPath = new Path();
            _drawPaint = new Paint
            {
                Color = _currentLineColor,
                AntiAlias = true,
                StrokeWidth = _penWidth
            };

            _drawPaint.SetStyle(Paint.Style.Stroke);
            _drawPaint.StrokeJoin = Paint.Join.Round;
            _drawPaint.StrokeCap = Paint.Cap.Round;

            _canvasPaint = new Paint
            {
                Dither = true
            };

            DrawingCacheEnabled = true;
            DrawingCacheBackgroundColor = Color.White;
        }

        protected override void OnSizeChanged(int w, int h, int oldw, int oldh)
        {
            base.OnSizeChanged(w, h, oldw, oldh);

            _canvasBitmap = Bitmap.CreateBitmap(w, h, Bitmap.Config.Argb8888);
            _drawCanvas = new Canvas(_canvasBitmap);
        }

        protected override void OnDraw(Canvas canvas)
        {
            base.OnDraw(canvas);

            _drawPaint.Color = _currentLineColor;
            canvas.DrawBitmap(_canvasBitmap, 0, 0, _canvasPaint);
            canvas.DrawPath(_drawPath, _drawPaint);
        }

        public override bool OnTouchEvent(MotionEvent e)
        {
            var touchX = e.GetX();
            var touchY = e.GetY();

            switch (e.Action)
            {
                case MotionEventActions.Down:
                    _drawPath.MoveTo(touchX, touchY);
                    break;
                case MotionEventActions.Move:
                    _drawPath.LineTo(touchX, touchY);
                    break;
                case MotionEventActions.Up:
                    _drawCanvas.DrawPath(_drawPath, _drawPaint);
                    _drawPath.Reset();
                    break;
                default:
                    return false;
            }

            Invalidate();

            return true;
        }

        public void Clear()
        {
            _drawCanvas = new Canvas(_canvasBitmap);
            Invalidate();
        }
    }
}