oracular (3) plvect.3plplot.gz

NAME

       plvect - Vector plot

SYNOPSIS

       plvect(u, v, nx, ny, scale, pltr, pltr_data)

DESCRIPTION

       Draws  a plot of vector data contained in the matrices (u[nx][ny],v[nx][ny]) . The scaling factor for the
       vectors is given by scale. A transformation routine pointed to by  pltr  with  a  pointer  pltr_data  for
       additional  data  required  by the transformation routine to map indices within the matrices to the world
       coordinates. The style of the vector arrow may be set using plsvect(3plplot).

       Redacted form: plvect(u, v, scale, pltr, pltr_data) where (see  above  discussion)  the  pltr,  pltr_data
       callback  arguments  are  sometimes replaced by a tr vector with 6 elements, or xg and yg array arguments
       with either one or two dimensions.

       This function is used in example 22.

ARGUMENTS

       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.

AUTHORS

       Many  developers  (who are credited at http://plplot.org/credits.php) have contributed to PLplot over its
       long history.

SEE ALSO

       PLplot documentation at http://plplot.org/documentation.php.

                                                  August, 2024                                   PLVECT(3plplot)