| 
	    plcont
	  ( | f, | 
| nx, | |
| ny, | |
| kx, | |
| lx, | |
| ky, | |
| ly, | |
| clevel, | |
| nlevel, | |
| pltr, | |
| pltr_data ); | 
Draws a contour plot of the data in
    f[nx][ny]nlevelclevelkxlxkylypltrpltr_data
f
	  (PLFLT_MATRIXA matrix containing data to be contoured.
nx, ny
	  (PLINT
	    The dimensions of the matrix
	    f
kx, lx
	  (PLINTRange of x indices to consider where
	  0 ≤ kx-1 < lx-1 < nx.  Values of
	  kx and lx are one-based rather
	  than zero-based for historical backwards-compatibility reasons.
	  
ky, ly
	  (PLINTRange of y indices to consider where
	  0 ≤ ky-1 < ly-1 < ny.  Values of
	  ky and ly are one-based rather
	  than zero-based for historical backwards-compatibility reasons.
	  
clevel
	  (PLFLT_VECTORA vector specifying the levels at which to draw contours.
nlevel
	  (PLINTNumber of contour levels to draw.
pltr
          (PLTRANSFORM_callback A callback function that defines the transformation
	  between the zero-based indices of the matrix
	  f
For the C case, transformation functions are provided
	  in the PLplot library: pltr0 for the identity mapping, and pltr1
	  and pltr2 for arbitrary mappings respectively defined by vectors and
	  matrices.  In addition, C callback routines for the transformation can
	  be supplied by the user such as the mypltr function
	  in examples/c/x09c.c which provides a general
	  linear transformation between index coordinates and world
	  coordinates.
For languages other than C you should consult Part III, “ Supported computer languages ” for the details concerning how
	  PLTRANSFORM_callback arguments are interfaced.
	  However, in general, a particular pattern of
	  callback-associated arguments such as a tr vector
	  with 6 elements; xg and yg
	  vectors; or xg and yg matrices
	  are respectively interfaced to a linear-transformation routine similar
	  to the above mypltr function; pltr1; and pltr2.
	  Furthermore, some of our more sophisticated bindings (see, e.g., Chapter 10, Fortran Language) support native language callbacks for handling
	  index to world-coordinate transformations.  Examples of these various
	  approaches are given in
	  examples/<language>x09*,
	  examples/<language>x16*,
	  examples/<language>x20*,
	  examples/<language>x21*, and
	  examples/<language>x22*, for all our
	  supported languages.
pltr_data
	  (PLPointerExtra parameter to help pass information to pltr0, pltr1,
	  pltr2, or whatever callback routine that is externally
	  supplied.
 Redacted form: plcont(f, kx, lx, ky, ly, clevel,
    pltr, pltr_data) where (see above discussion) the
    pltr, pltr_data callback arguments are sometimes replaced
    by a tr vector with 6 elements; xg
    and yg vectors; or xg
    and yg matrices.
This function is used in examples 9, 14, 16, and 22.