void pixtoline(int x, int y)
        {
            int xabs = Math.Abs( lastX-x);
            int yabs = Math.Abs(lastY-y);
            if (xabs > yabs)
            {
                double d = (double)(yabs / xabs);
                int j = 0;
                for (int i = 1; i < yabs; i++)
                {
                    j += (int)d;
                    if (lastX-x>0 & lastY-y>0)
                        mainpoint.Add(new Point(lastX+i,lastY+(int)Math.Floor((decimal)j)));
                    else if(lastX-x>0)
                        mainpoint.Add(new Point(lastX + i, lastY - (int)Math.Floor((decimal)j)));
                    else if(lastY-y>0)
                        mainpoint.Add(new Point(lastX - i, lastY + (int)Math.Floor((decimal)j)));
                    else
                        mainpoint.Add(new Point(lastX - i, lastY - (int)Math.Floor((decimal)j)));
                    if (mainpoint.Count > 0)
                        painter.DrawEllipse(new Pen(Color.Blue), mainpoint[mainpoint.Count - 1].X, mainpoint[mainpoint.Count - 1].Y, 1, 1);
                }
            }
            else
            {
                double d = (double)(xabs / yabs);
                int j = 0;
                for (int i = 1; i < xabs; i++)
                {
                    j += (int)d;
                    if (x - lastX > 0 & y - lastY > 0)
                        mainpoint.Add(new Point(lastX + (int)Math.Floor((decimal)j), lastY + i));
                    else if (x - lastX > 0)
                        mainpoint.Add(new Point(lastX + (int)Math.Floor((decimal)j), lastY - i));
                    else if (y - lastY >= 0)
                        mainpoint.Add(new Point(lastX - (int)Math.Floor((decimal)j), lastY+ i));
                    else
                        mainpoint.Add(new Point(lastX - (int)Math.Floor((decimal)j), lastY - i));
                    if (mainpoint.Count > 0)
                        painter.DrawEllipse(new Pen(Color.Blue), mainpoint[mainpoint.Count - 1].X, mainpoint[mainpoint.Count - 1].Y, 5, 5);

                }
            }
        }