GraphTart()

         Pie graph with Clipper!!

    Syntax:

         GraphTart ( nX, nY, nRadius, aArray ) -> Nil

         nX      : Coordinate X of the center of the circumference
         nY      : Coordinate Y of the center of the circumference
         nRadius : Radius of the circumference
         aArray  : An array of values for the graphic. It allows as
                   many elements as you like.

    Description:

         It generates a pie graph in Clipper. It only works in EGA
         and VGA.

         This function does not have the option to place title and legends
         because, as it allows you to place the graphic in a specific
         position, it may be of interest to place this data in whichever
         place you like.

         It is important to realize that the graphic will be painted in zones
         of different colors, always starting with color 1 in the first
         zone, 2 in the second, and so on until 15. This process will be
         recursively repeated if there is more than 15 zones. This is a
         very important point in order to determine later the color of
         each legend in the graphic.

         It is also important to realize that Fast offers the resources to
         rebuild this function if there is something in it that is not of your
         likeing. The only thing needed is some simple knowledge of Plain
         Geometry.

    Return:

         Nothing.

    Example:

         SetVGA()
         cTitulo := "Fast Graphic System"
         GraphTart ( 320, 240, 100, { 17, 3, 15, 60, 15 } )
         DispStr ( cTitulo, 320 - Len ( cTitulo ) * 4, 370, 15, 0 )
         Legend ( 320, 460, 15, 4, "Fast Library" )
         Inkey (0)
         TxtMode ()