RBOX x1, y1, w, h [, r] [,c] [,fill]
Draws a box with rounded corners on an attached LCD panel starting at ‘x1’ and ‘y1’ which is ‘w’ pixels wide and ‘h’ pixels high.
‘r’ is the radius of the corners of the box. It defaults to 10.
‘c’ specifies the color and defaults to the default foreground color if not specified.
‘fill’ is the fill color. It can be omitted or set to -1 in which case the box will not be filled.