NAME

       plshades - Shade regions on the basis of value

SYNOPSIS

       plshades(a,  nx,  ny,  defined,  xmin,  xmax,  ymin,  ymax,  clevel,  nlevel,  fill_width,
       cont_color, cont_width, fill, rectangular, pltr, pltr_data)

DESCRIPTION

       Shade regions on the basis of value.  This is the high-level routine for making continuous
       color  shaded  plots with cmap1 while plshade(3plplot) (or plshade1(3plplot)) are used for
       individual shaded regions using either cmap0 or cmap1. examples/c/x16c.c shows a number of
       examples  for  using  this function. See the following discussion of the arguments and the
       PLplot documentation for more information.

       Redacted form:  General: plshades(a, defined, xmin, xmax, ymin, ymax, clevel,  fill_width,
       cont_color,  cont_width,  fill,  rectangular, pltr, pltr_data) Perl/PDL: plshades(a, xmin,
       xmax, ymin, ymax, clevel, fill_width, cont_color, cont_width, fill, rectangular,  defined,
       pltr, pltr_data)

       This function is used in examples 16,21.

ARGUMENTS

       a (const PLFLT * const *, input)
              Contains  **  pointer  to array to be plotted. The array must have been declared as
              PLFLT a[nx][ny].

       nx (PLINT, input)
              First dimension of array "a".

       ny (PLINT, input)
              Second dimension of array "a".

       defined (PLINT (*) (PLFLT, PLFLT), input)
              User function specifying regions excluded from the  shading  plot.   This  function
              accepts x and y coordinates as input arguments and must return 0 if the point is in
              the excluded region or 1 otherwise. This argument can be NULL if all the values are
              valid.

       xmin (PLFLT, input)
              Defines  the  "grid"  coordinates.  The data a[0][0] has a position of (xmin,ymin),
              a[nx-1][0] has a position at (xmax,ymin) and so on.

       xmax (PLFLT, input)
              Defines the "grid" coordinates.  The data a[0][0] has a  position  of  (xmin,ymin),
              a[nx-1][0] has a position at (xmax,ymin) and so on.

       ymin (PLFLT, input)
              Defines  the  "grid"  coordinates.  The data a[0][0] has a position of (xmin,ymin),
              a[nx-1][0] has a position at (xmax,ymin) and so on.

       ymax (PLFLT, input)
              Defines the "grid" coordinates.  The data a[0][0] has a  position  of  (xmin,ymin),
              a[nx-1][0] has a position at (xmax,ymin) and so on.

       clevel (const PLFLT *, input)
              Pointer  to  array  containing  the  data levels corresponding to the edges of each
              shaded region that will be plotted by this function.  To work properly  the  levels
              should be monotonic.

       nlevel (PLINT, input)
              Number of shades plus 1 (i.e., the number of shade edge values in clevel).

       fill_width (PLFLT, input)
              Defines line width used by the fill pattern.

       cont_color (PLINT, input)
              Defines  pen  color  used  for  contours defining edges of shaded regions.  The pen
              color is only temporary set for the contour drawing.  Set this  value  to  zero  or
              less if no shade edge contours are wanted.

       cont_width (PLFLT, input)
              Defines  line width used for contours defining edges of shaded regions.  This value
              may not be honored by all drivers. The pen width is  only  temporary  set  for  the
              contour  drawing.   Set  this  value  to zero or less if no shade edge contours are
              wanted.

       fill (void (*) (PLINT, const PLFLT *, const PLFLT *), input)
              Routine used to fill the region.  Use plfill(3plplot).  Future  version  of  PLplot
              may have other fill routines.

       rectangular (PLBOOL, input)
              Set   rectangular  to  true  if  rectangles  map  to  rectangles  after  coordinate
              transformation with pltrl.  Otherwise, set rectangular to false. If rectangular  is
              set  to  true,  plshade  tries  to  save  time  by  filling large rectangles.  This
              optimization  fails  if  the  coordinate  transformation  distorts  the  shape   of
              rectangles. For example a plot in polar coordinates has to have  rectangular set to
              false.

       pltr (void (*) (PLFLT, PLFLT, PLFLT *, PLFLT *, PLPointer) , input)
              Pointer to function that defines transformation between indices in array z and  the
              world  coordinates  (C  only).  Transformation functions are provided in the PLplot
              library: pltr0(3plplot) for identity mapping, and pltr1(3plplot) and pltr2(3plplot)
              for arbitrary mappings respectively defined by one- and two-dimensional arrays.  In
              addition, user-supplied routines for  the  transformation  can  be  used  as  well.
              Examples  of  all  of  these  approaches are given in the PLplot documentation. The
              transformation function should have  the  form  given  by  any  of  pltr0(3plplot),
              pltr1(3plplot), or pltr2(3plplot).

       pltr_data (PLPointer, input)
              Extra  parameter  to  help  pass  information  to  pltr0(3plplot),  pltr1(3plplot),
              pltr2(3plplot), or whatever routine that is externally supplied.

AUTHORS

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

SEE ALSO

       PLplot documentation at http://plplot.sourceforge.net/documentation.php.

                                          February, 2016                        PLSHADES(3plplot)