plcont(f, nx, ny, kx,
lx, ky, ly, clevel, nlevel, pltr,
pltr_data)
Draws a contour plot of the data in
f[nx][ny], using the nlevel contour levels
specified by clevel. Only the region of the matrix from kx to
lx and from ky to ly is plotted out where all these
index ranges are interpreted as one-based for historical reasons. A
transformation routine pointed to by pltr with a generic pointer
pltr_data for additional data required by the transformation routine
is used to map indices within the matrix to the world coordinates.
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.
- f
(PLFLT_MATRIX(3plplot), input)
- A matrix containing data to be contoured.
- nx, ny
(PLINT(3plplot), input)
- The dimensions of the matrix f.
- kx, lx
(PLINT(3plplot), input)
- Range 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
(PLINT(3plplot), input)
- Range 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_VECTOR(3plplot), input)
- A vector specifying the levels at which to draw contours.
- nlevel
(PLINT(3plplot), input)
- Number of contour levels to draw.
- pltr
(PLTRANSFORM_callback(3plplot), input)
- A callback function that defines the transformation between the zero-based
indices of the matrix f and the world coordinates.For the C case,
transformation functions are provided in the PLplot library:
pltr0(3plplot) for the identity mapping, and pltr1(3plplot)
and pltr2(3plplot) 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 the PLplot documentation for the details concerning how
PLTRANSFORM_callback(3plplot) 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(3plplot); and pltr2(3plplot).
Furthermore, some of our more sophisticated bindings (see, e.g., the
PLplot documentation) 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
(PLPointer(3plplot), input)
- Extra parameter to help pass information to pltr0(3plplot),
pltr1(3plplot), pltr2(3plplot), or whatever callback routine
that is externally supplied.
Many developers (who are credited at
http://plplot.org/credits.php) have contributed to PLplot over its long
history.
PLplot documentation at http://plplot.org/documentation.php.