private void surfaceDessin_MouseMove(object sender, MouseEventArgs e)
        {
            Point p = e.GetPosition(surfaceDessin);

            textBlockPosition.Text = Math.Round(p.X) + ", " + Math.Round(p.Y) + "px";

            if (clicked)
            {
                DrawingAttributes attributes = new DrawingAttributes();

                // get attributes
                StylusPoint stylusPoint = new StylusPoint(p.X, p.Y, (float)0.5);
                StylusTip   stylusTip   = this.surfaceDessin.DefaultDrawingAttributes.StylusTip;
                Color       color       = this.surfaceDessin.DefaultDrawingAttributes.Color;
                double      width       = this.surfaceDessin.DefaultDrawingAttributes.Width;
                double      height      = this.surfaceDessin.DefaultDrawingAttributes.Height;



                // send to server
                ImagePoint pCoord = new ImagePoint(p.X, p.Y);

                string           action  = "";
                DrawPoint_Server segment = null;
                if (GlobalUser.OutilSelectionnee == "crayon" || GlobalUser.OutilSelectionnee == "efface_segment")
                {
                    action = "ADD";
                    this.trait.Add(p);
                    segment = new DrawPoint_Server("DRAW", action, this.traits.Count, new PointParams(stylusTip.ToString(), color.ToString(), width, height), pCoord);
                }

                else
                {
                    action = "DEL";
                    int index = 0;
                    foreach (var elem in traits)
                    {
                        foreach (var po in elem)
                        {
                            if (p.X >= po.X - 6 && p.X <= po.X + 6 && p.Y >= po.Y - 6 && p.Y <= po.Y + 6)
                            {
                                segment = new DrawPoint_Server("DRAW", action, index, new PointParams(stylusTip.ToString(), color.ToString(), width, height), pCoord);
                                this.surfaceDessin.Strokes[index].DrawingAttributes.Color = System.Windows.Media.Color.FromArgb(255, 255, 255, 255);

                                break;
                            }
                        }
                        index++;
                    }
                }
                if (segment != null && !activateTuto)
                {
                    var image = JsonConvert.SerializeObject(segment);
                    SocketService.MySocket.Emit("draw", image);
                }
            }
        }