using System; using System.Drawing; using System.Windows.Forms; namespace ArdupilotMega.Controls { internal static class PseudoOpacityHelper { public static void CoverWithRect(this Control c, Graphics g, float opacity) { var bgcolor = c.BackColor; int alpha = 255 - ((int)(opacity * 255)); Console.WriteLine("Alpha:" + alpha); var opacityColor = Color.FromArgb(alpha, bgcolor.R, bgcolor.G, bgcolor.B); using (var brush = new SolidBrush(opacityColor)) { g.FillRectangle(brush, 0, 0, c.Width, c.Height); } } } }