u,v (PLFLT_MATRIX(3plplot), input)
A pair of matrices containing the x and y components of the vector data to be plotted.
nx,ny (PLINT(3plplot), input)
Dimensions of the matrices u and v.
scale (PLFLT(3plplot), input)
Parameter to control the scaling factor of the vectors for plotting. If scale = 0 then the
scaling factor is automatically calculated for the data. If scale < 0 then the scaling factor is
automatically calculated for the data and then multiplied by -scale. If scale > 0 then the scaling
factor is set to scale.
pltr (PLTRANSFORM_callback(3plplot), input)
A callback function that defines the transformation between the zero-based indices of the matrices
u and v and 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.