plcont
( | f, |
| nx, | |
| ny, | |
| kx, | |
| lx, | |
| ky, | |
| ly, | |
| clevel, | |
| nlevel, | |
| pltr, | |
pltr_data); |
Draws a contour plot of the data in
,
using the f[nx][ny] contour
levels specified by nlevel.
Only the region of the matrix from
clevel to
kx and from
lx to
ky is plotted out where all
these index ranges are interpreted as one-based for historical
reasons. A transformation routine pointed to by
ly with a generic pointer
pltr for additional
data required by the transformation routine is used to map indices
within the matrix to the world coordinates.pltr_data
f
(PLFLT_MATRIX, input)
A matrix containing data to be contoured.
nx, ny
(PLINT, input)
The dimensions of the matrix
.
f
kx, lx
(PLINT, 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, 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, input)
A vector specifying the levels at which to draw contours.
nlevel
(PLINT, input)
Number of contour levels to draw.
pltr
(PLTRANSFORM_callback, input)
A callback function that defines the transformation
between the zero-based indices of the matrix
and the world coordinates.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
(PLPointer, input)
Extra 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.