1HAFTON(3NCARG) NCAR GRAPHICS HAFTON(3NCARG)
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6 HAFTON - draws a half-tone picture from data stored in a rectangular
7 array with the intensity in the picture proportional to the data value.
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10 This routine is part of the Halftone utility in NCAR Graphics. To see
11 the overview man page for this utility, type "man halftone".
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14 HAFTON is obsolete. It has been replaced by the CPCICA entry of the
15 Conpack contouring package.
16 HAFTON continues to be provided for compatibility of early NCAR
18 Graphics codes. If you are writing new code, we suggest that you use
19 CPCICA.
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22 CALL HAFTON (Z,L,M,N,FLO,HI,NLEV,NOPT,NPRM,ISPV,SPVAL)
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25 Z (an input array of type REAL) defining a two-dimensional
26 field to be half-tone plotted. A subset of Z of extent M by
27 N can be plotted.
28 L (an input parameter of type INTEGER) which is the first
30 dimension of the Z array.
31 M (an input parameter of type INTEGER) which is the extent of
33 the first dimension of array Z to be plotted. This allows
34 for a sub-array of Z to be plotted. M must be less than or
35 equal to L.
36 N (an input parameter of type INTEGER) which is the extent of
38 the second dimension of array Z to be plotted. This allows
39 for a sub-array of Z to be plotted. N must be less than or
40 equal to the second dimension of Z.
41 FLO (an input parameter of type REAL) defining a lowest level
43 for plotting. If FLO = HI = 0., the minimum value of Z
44 will be generated by HAFTON.
45 HI (an input parameter of type REAL) defining a highest level
47 for plotting. If HI = FLO = 0., the maximum value of Z
48 will be generated by HAFTON.
49 NLEL (an input parameter of type INTEGER) specifying the number
51 of intensity levels desired. 16 maximum. If NLEV = 0 or
52 1, 16 levels are used.
53 NOPT (an input parameter of type INTEGER) used to control the
55 mapping of Z onto the intensities. The sign of NOPT
56 controls the directness or inverseness of the mapping.
57 NOPT positive yields direct mapping. The largest value of
59 Z produces the most dense dots. On mechanical plotters,
60 large values of Z will produce a dark area on the paper.
61 With the film development methods used at NCAR, large
62 values of Z will produce many (white) dots on the film,
63 also resulting in a dark area on reader-printer paper.
64 NOPT negative yields inverse mapping. The smallest values
66 of Z produce the most dense dots resulting in dark areas on
67 the paper.
68 The absolute value of NOPT determines the mapping of Z onto
70 the intensities. For IABS(NOPT)
71 = 0 The mapping is linear. For
73 each intensity there is an equal
74 range in Z value.
75 = 1 The mapping is linear. For
77 each intensity there is an equal
78 range in Z value.
79 = 2 The mapping is exponential. For
81 larger values of Z, there is a
82 larger difference in intensity for
83 relatively close values of Z. Details
84 in the larger values of Z are displayed
85 at the expense of the smaller values
86 of Z.
87 = 3 The mapping is logarithmic, so
89 details of smaller values of Z are show
90 at the expense of larger values of Z.
91 = 4 Sinusoidal mapping, so mid-range values
93 of Z show details at the expense of
94 extreme values of Z.
95 = 5 Arcsine mapping, so extreme values of
97 Z are shown at the expense of mid-range
98 NPRM (an input parameter of type INTEGER) used to control the
100 drawing of a perimeter around the half-tone picture.
101 NPRM=0: The perimeter is drawn with ticks pointing at data
103 locations. (Side lengths are proportional to number of
104 data values.)
105 NPRM positive: No perimeter is drawn. The picture fills
107 the frame.
108 NPRM negative: The picture is within the confines of the
110 user's current viewport setting.
111 ISPV (an input parameter of type INTEGER) used to tell if the
113 special value feature is being used. The special value
114 feature is used to mark areas where the data is not known
115 or holes are wanted in the picture.
116 ISPV = 0: Special value feature not in use. SPVAL is
118 ignored.
119 ISPV non-zero: Special value feature in use. SPVAL
121 defines the special value. Where Z contains the special
122 value, no half-tone is drawn. If ISPV
123 = 0 Special value feature not in use.
125 SPVAL is ignored.
126 = 1 Nothing is drawn in special value
128 area.
129 = 2 Contiguous special value areas are
131 surrounded by a polygonal line.
132 = 3 Special value areas are filled
134 with X(s).
135 = 4 Special value areas are filled in
137 with the highest intensity.
138 SPVAL (an iput parameter of type REAL) used to denote missing
140 values in the Z array. This argument is ignored if ISPV =
141 0.
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144 To use HAFTON, load the NCAR Graphics libraries ncarg, ncarg_gks, and
145 ncarg_c, preferably in that order.
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148 Online: halftone, ezhftn, halftone_params, conpack, conpack_params,
149 cpcica
150 Hardcopy: NCAR Graphics Contouring and Mapping Tutorial; NCAR Graphics
152 Fundamentals, UNIX Version; User's Guide for NCAR GKS-0A Graphics
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155 Copyright (C) 1987-2009
156 University Corporation for Atmospheric Research
157 The use of this Software is governed by a License Agreement.
158UNIX March 1993 HAFTON(3NCARG)