private void button1_Click(object sender, EventArgs e)
        {
            PrintPreviewDialog ppd = new PrintPreviewDialog();
            System.Drawing.Printing.PrintDocument doc = new System.Drawing.Printing.PrintDocument();

            doc.PrintPage += (s, ev) =>
            {
                ev.Graphics.Clear(Color.White);
                float y = 0;
                float sizeY = ev.MarginBounds.Height;

                if (myBitmap != null)
                {
                    float x = ((ev.MarginBounds.Right - ev.MarginBounds.Left) / 2) - myBitmap.Width / 2;
                    ev.Graphics.DrawImage(myBitmap, new PointF(x, y));
                    y += myBitmap.Size.Height + 40;
                }


                float align;
                if (richTextBox1.SelectionAlignment == HorizontalAlignment.Left) align = 50;
                else if (richTextBox1.SelectionAlignment == HorizontalAlignment.Right) align = ev.MarginBounds.Right - 50;
                else align = ((ev.MarginBounds.Right - ev.MarginBounds.Left) / 2);

                ev.Graphics.DrawString(richTextBox1.Text, richTextBox1.SelectionFont, Brushes.Black, align, y);
                ev.Graphics.PageUnit = GraphicsUnit.Inch;
            };

            ppd.Document = doc;
            ppd.ShowDialog();

        }