| a
	  (PLFLT **, input)             Contains ** pointer to array to be plotted. The array must have been declared
	     as PLFLT a[nx][ny].
	  nx
	  (PLINT, input)            First dimension of array "a".
	  ny
	  (PLINT, input)            Second dimension of array "a".
	  defined
	  (PLINT (*) (PLFLT, PLFLT), input)	    User function specifying regions excluded from the shading
            plot.  This function accepts x and y coordinates as input
            arguments and must return 0 if the point is in the excluded
            region or 1 otherwise. This argument can be NULL if all the
            values are valid.
	  xmin
	  (PLFLT, input)             Defines the "grid" coordinates.  The data a[0][0] has a
	     position of (xmin,ymin), a[nx-1][0] has a position at (xmax,ymin)
	     and so on.
(xmax,ymin)
	  xmax
	  (PLFLT, input)             Defines the "grid" coordinates.  The data a[0][0] has a
	     position of (xmin,ymin), a[nx-1][0] has a position at (xmax,ymin)
	     and so on.
	  ymin
	  (PLFLT, input)             Defines the "grid" coordinates.  The data a[0][0] has a
	     position of (xmin,ymin), a[nx-1][0] has a position at (xmax,ymin)
	     and so on.
	  ymax
	  (PLFLT, input)             Defines the "grid" coordinates.  The data a[0][0] has a
	     position of (xmin,ymin), a[nx-1][0] has a position at (xmax,ymin)
	     and so on.
	  clevel
	  (PLFLT *, input)            Pointer to array containing the data levels corresponding to
	    the edges of each shaded region that will be plotted by this
	    function.  To work properly the levels should be monotonic.
	  nlevel
	  (PLINT, input)            Number of shades plus 1 (i.e., the number of shade edge values
	    in clevel).
	  fill_width
	  (PLINT, input)            Defines width used by the fill pattern.
	  cont_color
	  (PLINT, input)            Defines pen color used for contours defining edges of shaded
	    regions.  The pen color is only temporary set for the
	    contour drawing.  Set this value to zero or less if no shade edge contours are wanted.
	  cont_width
	  (PLINT, input)            Defines pen width used for contours defining edges of shaded
	    regions.  This value may not be honored by all drivers.
	    The pen width is only temporary set for the
	    contour drawing.  Set this value to zero or less if no shade edge contours are wanted.
	  fill
	  (void (*) (PLINT, PLFLT *, PLFLT *), input)            Routine used to fill the region.  Use plfill.  Future version of
	    PLplot may have other fill routines.rectangular
	  (PLINT, input)	  Set rectangular to 1
	  if rectangles map to rectangles after coordinate transformation
	  with pltrl.  Otherwise,
	  set rectangular to 0.
	  If rectangular
	  is set to 1, plshade tries to save time by
	  filling large rectangles.  This optimization fails if
	  the coordinate transformation distorts the shape of rectangles.
	  For example a plot in polor coordinates has to have rectangular
	  set to 0.
	  pltr
	  (void (*) (PLFLT, PLFLT, PLFLT *, PLFLT *, PLPointer)
           , input)	    Pointer to function that defines transformation between indices
	    in array z and the
	    world coordinates (C only).  Transformation functions are
	    provided in the PLplot library:
	    pltr0for identity mapping, andpltr1andpltr2for
	    arbitrary mappings respectively defined by one- and
	    two-dimensional arrays.  In addition, user-supplied routines
	    for the transformation can be used as well.  Examples of
	    all of these approaches are given in
	    the Section called Contour Plots from C in Chapter 3.
	    The transformation function should
	    have the form given by any ofpltr0,pltr1, orpltr2.pltr_data
	  (PLPointer, input)	    Extra parameter to help
	    pass information to pltr0,pltr1,pltr2, or whatever routine
	    that is externally supplied.
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