[Napisz sam] Program do pisania ręcznego (np tablet) z anima

//XAML
<ComboBox x:Name="cboBrushSize" HorizontalAlignment="Left" Margin="568,195,0,0" VerticalAlignment="Top" Width="120" SelectionChanged="ComboBox_SelectionChanged">
            <ComboBoxItem>1</ComboBoxItem>
            <ComboBoxItem IsSelected="True">2</ComboBoxItem>
            <ComboBoxItem>4</ComboBoxItem>
            <ComboBoxItem>6</ComboBoxItem>
            <ComboBoxItem>8</ComboBoxItem>
            <ComboBoxItem>10</ComboBoxItem>
</ComboBox>

//---------------------------

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.IO;
using Microsoft.Win32;
using System.Windows.Forms;
using System.Windows.Media.Animation;

namespace AndrzejIwaniuk
{
    /// <summary>
    /// Eksport obrazka do formatu JPEG
    /// Zmiana kolorów linii
    /// Prosta animacja
    /// </summary>

    public partial class MainWindow : Window
    {

        string nazwaPliku = "";
        static System.Windows.Media.Color col;
        //static System.Drawing.Color col;
        public MainWindow()
        {
            InitializeComponent();
        }

        private void btnCzysc_Click(object sender, RoutedEventArgs e)
        {
            //czyść obszar pisania
            recznePisanie.Strokes.Clear();

        }

        //zapisz obrazek jako plik JPG
        public void EskportDoJPEG(InkCanvas obszar)
        {
            double
                    x1 = obszar.Margin.Left,
                    x2 = obszar.Margin.Top,
                    x3 = obszar.Margin.Right,
                    x4 = obszar.Margin.Bottom;

            obszar.Margin = new Thickness(0, 0, 0, 0);

            Size size = new Size(obszar.Width, obszar.Height);
            obszar.Measure(size);
            obszar.Arrange(new Rect(size));

            RenderTargetBitmap renderBitmap =
             new RenderTargetBitmap(
               (int)size.Width,
               (int)size.Height,
               96,
               96,
               PixelFormats.Default);
            renderBitmap.Render(obszar);

            otworzOknoDialogoZapisz();

            try
            {
                using (FileStream fs = File.Open(nazwaPliku, FileMode.Create))
                {
                    JpegBitmapEncoder encoder = new JpegBitmapEncoder();
                    encoder.Frames.Add(BitmapFrame.Create(renderBitmap));
                    encoder.Save(fs);
                }
            }
            catch (Exception e)
            {
            }
            obszar.Margin = new Thickness(x1, x2, x3, x4);
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            EskportDoJPEG(recznePisanie);
        }
        void otworzOknoDialogoZapisz()
        {
            //otworz save dialog box
            // konfiguracja okna dialogowego Zapisu
            Microsoft.Win32.SaveFileDialog dlg = new Microsoft.Win32.SaveFileDialog();
            dlg.FileName = "nazwa_pliku"; // domyślna nazwa pliku
            dlg.DefaultExt = ".jpg"; // domyśle rozszerzenie pliku
            dlg.Filter = "Obrazek (.jpg)|*.jpg"; // pokauj tylko pliku *.jpg

            // Pokaz okno dialogowe Zapisu
            Nullable<bool> result = dlg.ShowDialog();

            // Sprawdź zmienna result z okna Dialogowe Zapis

            if (result == true)
            {
                // Zapisanie dokumentu
                nazwaPliku = dlg.FileName;
            }
            //------
        }
        private void koloDialog()
        //private System.Windows.Media.Color koloDialog()
        {
            ColorDialog colorDialog =
                       new ColorDialog();
            colorDialog.AllowFullOpen = true;
            colorDialog.ShowDialog();
            //col = colorDialog.Color;
            col.A = colorDialog.Color.A;
            col.B = colorDialog.Color.B;
            col.G = colorDialog.Color.G;
            col.R = colorDialog.Color.R;

        }

        private void btnKolory_Click(object sender, RoutedEventArgs e)
        {
            koloDialog();
            ChangeColor(recznePisanie, col);
        }

        void ChangeColor(InkCanvas inkCanvas, System.Windows.Media.Color color)
        //void ChangeColor(InkCanvas inkCanvas, Color color)
        {
            //foreach (var stroke in inkCanvas.Strokes)
            //{
                //stroke.DrawingAttributes.Color = Colors.Aqua;// col;

            inkCanvas.DefaultDrawingAttributes.Color = Color.FromArgb(col.A, col.R, col.G, col.B);
            //stroke.DrawingAttributes.Color = Color.FromArgb(col.A,col.R,col.G,col.B);

            //}

        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            DoubleAnimation da = new DoubleAnimation
              (360, 0, new Duration(TimeSpan.FromSeconds(3)));
            RotateTransform rt = new RotateTransform();

            image1.RenderTransform = rt;
            image1.RenderTransformOrigin = new Point(0.5, 0.5);
            da.RepeatBehavior = RepeatBehavior.Forever;
            rt.BeginAnimation(RotateTransform.AngleProperty, da);
        }

        private void ComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (cboBrushSize.Items.Count > 0 && ((ComboBoxItem)cboBrushSize.SelectedItem).Content != null)
            {
                /// Sets the brush size.
                recznePisanie.DefaultDrawingAttributes.Width =      Convert.ToDouble(((ComboBoxItem)cboBrushSize.SelectedItem).Content);
                recznePisanie.DefaultDrawingAttributes.Height = Convert.ToDouble(((ComboBoxItem)cboBrushSize.SelectedItem).Content);
            }
        }

        private void image1_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            recznePisanie.Background = Brushes.DarkSlateBlue;
        }
    }
}