public static void DrawRoundRectangle (Context cr, double x, double y, double r, double w, double h) { const double ARC_TO_BEZIER = 0.55228475; double radius_x = r; double radius_y = r / 4; if (radius_x > w - radius_x) radius_x = w / 2; if (radius_y > h - radius_y) radius_y = h / 2; double c1 = ARC_TO_BEZIER * radius_x; double c2 = ARC_TO_BEZIER * radius_y; cr.NewPath (); cr.MoveTo (x + radius_x, y); cr.RelLineTo (w - 2 * radius_x, 0.0); cr.RelCurveTo (c1, 0.0, radius_x, c2, radius_x, radius_y); cr.RelLineTo (0, h - 2 * radius_y); cr.RelCurveTo (0.0, c2, c1 - radius_x, radius_y, -radius_x, radius_y); cr.RelLineTo (-w + 2 * radius_x, 0); cr.RelCurveTo (-c1, 0, -radius_x, -c2, -radius_x, -radius_y); cr.RelLineTo (0, -h + 2 * radius_y); cr.RelCurveTo (0.0, -c2, radius_x - c1, -radius_y, radius_x, -radius_y); cr.ClosePath (); }