1PLSHADES(3plplot) PLplot API PLSHADES(3plplot)
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6 plshades - Shade regions on the basis of value
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9 plshades(a, nx, ny, defined, xmin, xmax, ymin, ymax, clevel, nlevel,
10 fill_width, cont_color, cont_width, fill, rectangular, pltr, pltr_data)
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13 Shade regions on the basis of value. This is the high-level routine
14 for making continuous color shaded plots with cmap1 while
15 plshade(3plplot) should be used to plot individual shaded regions using
16 either cmap0 or cmap1. examples/;<language>/x16* shows how to use
17 plshades(3plplot) for each of our supported languages.
18 Redacted form: General: plshades(a, defined, xmin, xmax, ymin, ymax,
20 clevel, fill_width, cont_color, cont_width, fill, rectangular, pltr,
21 pltr_data)
22 This function is used in examples 16, 21, and 22.
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27 a (PLFLT_MATRIX(3plplot), input)
28 A matrix containing function values to plot. Should have dimen‐
29 sions of nx by ny.
30 nx (PLINT(3plplot), input)
32 First dimension of matrix "a".
33 ny (PLINT(3plplot), input)
35 Second dimension of matrix "a".
36 defined (PLDEFINED_callback(3plplot), input)
38 Callback function specifying the region that should be plotted
39 in the shade plot. This function accepts x and y coordinates as
40 input arguments and must return 1 if the point is to be included
41 in the shade plot and 0 otherwise. If you want to plot the en‐
42 tire shade plot (the usual case), this argument should be set to
43 NULL.
44 xmin, xmax, ymin, ymax (PLFLT(3plplot), input)
46 See the discussion of pltr below for how these arguments are
47 used (only for the special case when the callback function pltr
48 is not supplied).
49 clevel (PLFLT_VECTOR(3plplot), input)
51 A vector containing the data levels corresponding to the edges
52 of each shaded region that will be plotted by this function. To
53 work properly the levels should be monotonic.
54 nlevel (PLINT(3plplot), input)
56 Number of shades plus 1 (i.e., the number of shade edge values
57 in clevel).
58 fill_width (PLFLT(3plplot), input)
60 Defines the line width used by the fill pattern.
61 cont_color (PLINT(3plplot), input)
63 Defines cmap0 pen color used for contours defining edges of
64 shaded regions. The pen color is only temporary set for the
65 contour drawing. Set this value to zero or less if no shade
66 edge contours are wanted.
67 cont_width (PLFLT(3plplot), input)
69 Defines line width used for contours defining edges of shaded
70 regions. This value may not be honored by all drivers. The pen
71 width is only temporary set for the contour drawing. Set this
72 value to zero or less if no shade edge contours are wanted.
73 fill (PLFILL_callback(3plplot), input)
75 Callback routine used to fill the region. Use plfill(3plplot)
76 for this purpose.
77 rectangular (PLBOOL(3plplot), input)
79 Set rectangular to true if rectangles map to rectangles after
80 coordinate transformation with pltrl. Otherwise, set rectangu‐
81 lar to false. If rectangular is set to true, plshade tries to
82 save time by filling large rectangles. This optimization fails
83 if the coordinate transformation distorts the shape of rectan‐
84 gles. For example a plot in polar coordinates has to have rec‐
85 tangular set to false.
86 pltr (PLTRANSFORM_callback(3plplot), input)
88 A callback function that defines the transformation between the
89 zero-based indices of the matrix a and world coordinates. If
90 pltr is not supplied (e.g., is set to NULL in the C case), then
91 the x indices of a are mapped to the range xmin through xmax and
92 the y indices of a are mapped to the range ymin through ymax.For
93 the C case, transformation functions are provided in the PLplot
94 library: pltr0(3plplot) for the identity mapping, and
95 pltr1(3plplot) and pltr2(3plplot) for arbitrary mappings respec‐
96 tively defined by vectors and matrices. In addition, C callback
97 routines for the transformation can be supplied by the user such
98 as the mypltr function in examples/c/x09c.c which provides a
99 general linear transformation between index coordinates and
100 world coordinates.For languages other than C you should consult
101 the PLplot documentation for the details concerning how PLTRANS‐
102 FORM_callback(3plplot) arguments are interfaced. However, in
103 general, a particular pattern of callback-associated arguments
104 such as a tr vector with 6 elements; xg and yg vectors; or xg
105 and yg matrices are respectively interfaced to a linear-trans‐
106 formation routine similar to the above mypltr function;
107 pltr1(3plplot); and pltr2(3plplot). Furthermore, some of our
108 more sophisticated bindings (see, e.g., the PLplot documenta‐
109 tion) support native language callbacks for handling index to
110 world-coordinate transformations. Examples of these various ap‐
111 proaches are given in examples/<language>x09*, examples/<lan‐
112 guage>x16*, examples/<language>x20*, examples/<language>x21*,
113 and examples/<language>x22*, for all our supported languages.
114 pltr_data (PLPointer(3plplot), input)
116 Extra parameter to help pass information to pltr0(3plplot),
117 pltr1(3plplot), pltr2(3plplot), or whatever routine that is ex‐
118 ternally supplied.
119
122 Many developers (who are credited at http://plplot.org/credits.php)
123 have contributed to PLplot over its long history.
124
126 PLplot documentation at http://plplot.org/documentation.php.
127 January, 2023 PLSHADES(3plplot)