1PLVECT(3plplot)                   PLplot API                   PLVECT(3plplot)
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NAME

6       plvect - Vector plot
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SYNOPSIS

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

12       Draws   a   plot   of   vector   data   contained   in   the   matrices
13       (u[nx][ny],v[nx][ny]) . The scaling factor for the vectors is given  by
14       scale.  A  transformation  routine  pointed  to  by pltr with a pointer
15       pltr_data for additional data required by the transformation routine to
16       map  indices within the matrices to the world coordinates. The style of
17       the vector arrow may be set using plsvect(3plplot).
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19       Redacted form: plvect(u, v, scale, pltr, pltr_data)  where  (see  above
20       discussion)  the  pltr,  pltr_data  callback  arguments  are  sometimes
21       replaced by a tr vector with 6 elements, or xg and yg  array  arguments
22       with either one or two dimensions.
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24       This function is used in example 22.
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ARGUMENTS

27       u, v (PLFLT_MATRIX(3plplot), input)
28              A pair of matrices containing the x and y components of the vec‐
29              tor data to be plotted.
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31       nx, ny (PLINT(3plplot), input)
32              Dimensions of the matrices u and v.
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34       scale (PLFLT(3plplot), input)
35              Parameter to control the scaling factor of the vectors for plot‐
36              ting.  If  scale  =  0  then the scaling factor is automatically
37              calculated for the data. If scale < 0 then the scaling factor is
38              automatically  calculated  for  the  data and then multiplied by
39              -scale. If scale > 0 then the scaling factor is set to scale.
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41       pltr (PLTRANSFORM_callback(3plplot), input)
42              A callback function that defines the transformation between  the
43              zero-based  indices  of  the  matrices u and v and world coordi‐
44              nates.For the C case, transformation functions are  provided  in
45              the PLplot library: pltr0(3plplot) for the identity mapping, and
46              pltr1(3plplot) and pltr2(3plplot) for arbitrary mappings respec‐
47              tively defined by vectors and matrices.  In addition, C callback
48              routines for the transformation can be supplied by the user such
49              as  the  mypltr  function  in examples/c/x09c.c which provides a
50              general linear  transformation  between  index  coordinates  and
51              world  coordinates.For languages other than C you should consult
52              the PLplot documentation for the details concerning how PLTRANS‐
53              FORM_callback(3plplot)  arguments  are  interfaced.  However, in
54              general, a particular pattern of  callback-associated  arguments
55              such  as  a  tr vector with 6 elements; xg and yg vectors; or xg
56              and yg matrices are respectively interfaced to  a  linear-trans‐
57              formation   routine   similar  to  the  above  mypltr  function;
58              pltr1(3plplot); and pltr2(3plplot).  Furthermore,  some  of  our
59              more  sophisticated  bindings  (see, e.g., the PLplot documenta‐
60              tion) support native language callbacks for  handling  index  to
61              world-coordinate  transformations.   Examples  of  these various
62              approaches are given in examples/<language>x09*,  examples/<lan‐
63              guage>x16*,   examples/<language>x20*,  examples/<language>x21*,
64              and examples/<language>x22*, for all our supported languages.
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66       pltr_data (PLPointer(3plplot), input)
67              Extra parameter to  help  pass  information  to  pltr0(3plplot),
68              pltr1(3plplot),  pltr2(3plplot),  or  whatever  callback routine
69              that is externally supplied.
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AUTHORS

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

77       PLplot documentation at http://plplot.org/documentation.php.
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81                                February, 2019                 PLVECT(3plplot)
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