A matrix of values (intensities) to plot. Should have dimensions of nx by ny.

Dimensions of idata

See the discussion of pltr below for how these arguments are used (only for the special case when the callback function pltr is not supplied).

Only data between zmin and zmax (inclusive) will be plotted.

The minimum and maximum data values to use for value to color mappings. A datum equal to or less than valuemin will be plotted with color 0.0, while a datum equal to or greater than valuemax will be plotted with color 1.0. Data between valuemin and valuemax map linearly to colors in the range (0.0-1.0).

A callback function that defines the transformation between the zero-based indices of the matrix idata and world coordinates. If pltr is not supplied (e.g., is set to NULL in the C case), then the x indices of idata are mapped to the range xmin through xmax and the y indices of idata are mapped to the range ymin through ymax.

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.

Extra parameter to help pass information to pltr0, pltr1, pltr2, or whatever routine is externally supplied.