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

6       plshade - Shade individual region on the basis of value
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SYNOPSIS

9       plshade(a,   nx,  ny,  defined,  xmin,  xmax,  ymin,  ymax,  shade_min,
10       shade_max,   sh_cmap,   sh_color,   sh_width,   min_color,   min_width,
11       max_color, max_width, fill, rectangular, pltr, pltr_data)
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DESCRIPTION

14       Shade  individual  region on the basis of value.  Use plshades(3plplot)
15       if you want to shade a number of contiguous  regions  using  continuous
16       colors.   In  particular  the  edge  contours  are  treated properly in
17       plshades(3plplot).  If  you  attempt  to  do  contiguous  regions  with
18       plshade(3plplot)  the  contours  at the edge of the shade are partially
19       obliterated by subsequent plots of contiguous shaded regions.
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21       Redacted form: General: plshade(a, defined,  xmin,  xmax,  ymin,  ymax,
22       shade_min,   shade_max,   sh_cmap,   sh_color,   sh_width,   min_color,
23       min_width, max_color, max_width, fill, rectangular, pltr, pltr_data)
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26       This function is used in example 15.
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ARGUMENTS

29       a (PLFLT_MATRIX(3plplot), input)
30              A matrix containing function values to plot.  Should have dimen‐
31              sions of nx by ny.
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33       nx (PLINT(3plplot), input)
34              First dimension of the matrix "a".
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36       ny (PLINT(3plplot), input)
37              Second dimension of the matrix "a".
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39       defined (PLDEFINED_callback(3plplot), input)
40              Callback  function  specifying the region that should be plotted
41              in the shade plot.  This function accepts x and y coordinates as
42              input arguments and must return 1 if the point is to be included
43              in the shade plot and 0 otherwise.  If you want to plot the  en‐
44              tire shade plot (the usual case), this argument should be set to
45              NULL.
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47       xmin, xmax, ymin, ymax (PLFLT(3plplot), input)
48              See the discussion of pltr below for  how  these  arguments  are
49              used  (only for the special case when the callback function pltr
50              is not supplied).
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52       shade_min (PLFLT(3plplot), input)
53              Defines the lower end of the interval to be shaded. If shade_max
54              <= shade_min, plshade(3plplot) does nothing.
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56       shade_max (PLFLT(3plplot), input)
57              Defines the upper end of the interval to be shaded. If shade_max
58              <= shade_min, plshade(3plplot) does nothing.
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60       sh_cmap (PLINT(3plplot), input)
61              Defines color map. If sh_cmap=0, then sh_color is interpreted as
62              a  cmap0 (integer) index.  If sh_cmap=1, then sh_color is inter‐
63              preted as a cmap1 argument in the range (0.0-1.0).
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65       sh_color (PLFLT(3plplot), input)
66              Defines color map index with integer value if cmap0 or value  in
67              range (0.0-1.0) if cmap1.
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69       sh_width (PLFLT(3plplot), input)
70              Defines width used by the fill pattern.
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72       min_color (PLINT(3plplot), input)
73              Defines  pen color, width used by the boundary of shaded region.
74              The min values are used for the shade_min boundary, and the  max
75              values  are used on the shade_max boundary.  Set color and width
76              to zero for no plotted boundaries.
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78       min_width (PLFLT(3plplot), input)
79              Defines pen color, width used by the boundary of shaded  region.
80              The  min values are used for the shade_min boundary, and the max
81              values are used on the shade_max boundary.  Set color and  width
82              to zero for no plotted boundaries.
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84       max_color (PLINT(3plplot), input)
85              Defines  pen color, width used by the boundary of shaded region.
86              The min values are used for the shade_min boundary, and the  max
87              values  are used on the shade_max boundary.  Set color and width
88              to zero for no plotted boundaries.
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90       max_width (PLFLT(3plplot), input)
91              Defines pen color, width used by the boundary of shaded  region.
92              The  min values are used for the shade_min boundary, and the max
93              values are used on the shade_max boundary.  Set color and  width
94              to zero for no plotted boundaries.
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96       fill (PLFILL_callback(3plplot), input)
97              Routine  used  to fill the region.  Use plfill(3plplot).  Future
98              version of PLplot may have other fill routines.
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100       rectangular (PLBOOL(3plplot), input)
101              Set rectangular to true if rectangles map  to  rectangles  after
102              coordinate  transformation with pltrl.  Otherwise, set rectangu‐
103              lar to false. If rectangular is set to true,  plshade  tries  to
104              save  time by filling large rectangles.  This optimization fails
105              if the coordinate transformation distorts the shape  of  rectan‐
106              gles.  For  example a plot in polar coordinates has to have rec‐
107              tangular set to false.
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109       pltr (PLTRANSFORM_callback(3plplot), input)
110              A callback function that defines the transformation between  the
111              zero-based  indices  of  the  matrix a and world coordinates. If
112              pltr is not supplied (e.g., is set to NULL in the C case),  then
113              the x indices of a are mapped to the range xmin through xmax and
114              the y indices of a are mapped to the range ymin through ymax.For
115              the  C case, transformation functions are provided in the PLplot
116              library:  pltr0(3plplot)   for   the   identity   mapping,   and
117              pltr1(3plplot) and pltr2(3plplot) for arbitrary mappings respec‐
118              tively defined by vectors and matrices.  In addition, C callback
119              routines for the transformation can be supplied by the user such
120              as the mypltr function in  examples/c/x09c.c  which  provides  a
121              general  linear  transformation  between  index  coordinates and
122              world coordinates.For languages other than C you should  consult
123              the PLplot documentation for the details concerning how PLTRANS‐
124              FORM_callback(3plplot) arguments  are  interfaced.  However,  in
125              general,  a  particular pattern of callback-associated arguments
126              such as a tr vector with 6 elements; xg and yg  vectors;  or  xg
127              and  yg  matrices are respectively interfaced to a linear-trans‐
128              formation  routine  similar  to  the  above   mypltr   function;
129              pltr1(3plplot);  and  pltr2(3plplot).  Furthermore,  some of our
130              more sophisticated bindings (see, e.g.,  the  PLplot  documenta‐
131              tion)  support  native  language callbacks for handling index to
132              world-coordinate transformations.  Examples of these various ap‐
133              proaches  are  given  in examples/<language>x09*, examples/<lan‐
134              guage>x16*,  examples/<language>x20*,   examples/<language>x21*,
135              and examples/<language>x22*, for all our supported languages.
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137       pltr_data (PLPointer(3plplot), input)
138              Extra  parameter  to  help  pass  information to pltr0(3plplot),
139              pltr1(3plplot), pltr2(3plplot), or whatever routine that is  ex‐
140              ternally supplied.
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AUTHORS

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

148       PLplot documentation at http://plplot.org/documentation.php.
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152                                 January, 2021                PLSHADE(3plplot)
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