SUBROUTINE SHADE

The  SHADE subroutine fills in the  area inclosed by the line defined by the x and y arrays with equally spaced lines at a given angle using a specified line type. The first and last point of the x and y array are assumed to be connected.

CALL SHADE (x,y,n,i,l,d,t,w,ma,xm,dx,ym,dy)

x     (R): array of x values
y     (R): array of y values
n     (I): number of points in array
i     (I): increment between points
l     (I): shade format control
           = -3 : clear area and outline
           = -2 : clear area
           = -1 : clear outline
           =  0 : no action
           =  1 : draw outline
           =  2 : shade area
           =  3 : shade area and outline
d     (R): distance between shading lines
t     (R): angle of shading lines in degrees
w     (R): working array dimensioned at least 3*n
ma    (R): line type of shading
            => 0 : line type (see NEWPEN)
xm    (R): minmum scale factor for x (see LINE)
dx    (R): x increment scale factor
ym    (R): minmum scale factor for y
dy    (R): y increment scale factor