private void btnDrawLineByPoints_Click(object sender, EventArgs e)
{
PointFZuma p1 = new PointFZuma(float.Parse(txtX1.Text), float.Parse(txtY1.Text));
PointFZuma p2 = new PointFZuma(float.Parse(txtX2.Text), float.Parse(txtY2.Text));
Field field = new Field(400, 350);
LinePath path = new LinePath(field, p1, p2);
for (int i = 0; i < path.Points.Length; i++)
{
PointFZuma p = path.Points[i];
((Bitmap)pictureBox3.Image).SetPixel((int)p.X, (int)p.Y, Color.Red);
}
pictureBox3.Invalidate();
}