1SPPS_converters(3NCARG) NCAR GRAPHICS SPPS_converters(3NCARG)
2
6 spps_converters - A set of functions, each of which transforms a
7 coordinate from one of the NCAR Graphics coordinate systems to another.
8 The complete list of functions is as follows: CFUX, CFUY, CMFX, CMFY,
9 CMUX, CMUY, CPFX, CPFY, CPUX, CPUY, CUFX, CUFY, KFMX, KFMY, KFPX, KFPY,
10 KMPX, KMPY, KPMX, KPMY, KUMX, KUMY, KUPX, and KUPY.
11
13 Plotter Address Units (PAUs) and Metacode Units (MUs) are no longer
14 used in NCAR Graphics; thus, all functions with either an M or a P as
15 the second or third letter of the function name are considered
16 obsolete.
17 The current recognized coordinate systems are GKS world coordinates,
19 GKS normalized device coordinates, NCAR Graphics fractional
20 coordinates, and NCAR Graphics user coordinates. See the NCAR Graphics
21 document "NCAR Graphics Fundamentals, UNIX Version" for descriptions of
22 these coordinate systems.
23 The following definitions of the PAU coordinate system and the MU
25 coordinate system are provided for the purpose of interpreting and
26 converting codes which use PAUs or MUs:
27 The plotter coordinates of a point are integers IPX and IPY, where IPX
29 is between 1 and 2**MX and IPY is between 1 and 2**MY. MX and MY are
30 internal parameters of SPPS; each has a default value of 10. Values of
31 MX and MY can be set by calling the routines SETI or SETUSV and
32 retrieved by calling the routines GETSI or GETUSV.
33 The metacode coordinates of a point are integers IMX and IMY between 0
35 and 32767 inclusive. The area addressed is a square in a "metacode
36 space" that is usually mapped into a square subset of the addressable
37 area of the plotting device. Metacode coordinates were used in calls
38 to the routine PLOTIT and are returned in calls to FL2INT.
39
41 Current:
42 X = CFUX (RX), Y = CFUY(RY)
43 X = CUFX (RX), Y = CUFY(RY)
44 Obsolete:
46 X = CMUX (IX), Y = CMUY(IY)
47 X = CPUX (IX), Y = CPUY(IY)
48 X = CMFX (IX), Y = CMFY(IY)
49 X = CPFX (IX), Y = CPFY(IY)
50 I = KFMX (RX), J = KFMY(RY)
51 I = KUMX (RX), J = KUMY(RY)
52 I = KFPX (RX), J = KFPY(RY)
53 I = KUPX (RX), J = KUPY(RY)
54 I = KPMX (IX), J = KPMY(IY)
55 I = KMPX (IX), J = KMPY(IY)
56
58 #include <ncarg/ncargC.h>
59 float c_cfux (float rx)
61 float c_cfuy (float ry)
63 float c_cufx (float rx)
65 float c_cufy (float ry)
67
69 RX (an input expression of type REAL) is an X coordinate in
70 the coordinate system specified by the second letter of the
71 function name. In a reference to CFUX, RX is a fractional
72 X coordinate; in a reference to CUFX, RX is a user X
73 coordinate.
74 RY (an input expression of type REAL) is a Y coordinate in the
76 coordinate system specified by the second letter of the
77 function name. In a reference to CFUY, RY is a fractional
78 Y coordinate; in a reference to CUFY, RY is a user Y
79 coordinate.
80 IX and IY occur as arguments only in references to some of the obsolete
82 functions; they represent input expressions of type INTEGER, specifying
83 the X and Y coordinates of a point in either PAUs or MUs (depending on
84 the second letter of the function name).
85 The first letter of the function name is a C if the result is of type
87 REAL and a K if the result is of type INTEGER (the latter only happens
88 for some of the obsolete ones). This conforms to the usual FORTRAN
89 convention for implicit typing.
90 The second letter of the function name specifies the coordinate system
92 of the argument.
93 The third letter of the function name specifies the coordinate system
95 of the functional result. In references to CFUX and CFUY, the result
96 is in the user system; in references to CUFX and CUFY, the result is in
97 the fractional system.
98 The fourth letter of the function name is an X or a Y, depending on
100 whether an X or a Y coordinate is being converted.
101
103 The C-binding argument description is the same as the FORTRAN argument
104 description.
105
107 Use the ncargex command to see the following relevant examples which
108 use coordinate converters: mpex10, cbex01, sfex02, epltch.
109 The command "ncargex -n mpex10" will load the driver mpex10.f into your
111 current working directory where you can examine the file using a local
112 editor, or the UNIX more command.
113
115 There were 24 conversion functions in the original set. These
116 functions (12 for the X coordinate of a point, and 12 for the Y
117 coordinate), allowed one to convert between any combination of PAUs,
118 MUs, fractional coordinates, and user coordinates. PAUs and MUs are
119 now obsolete; thus, only four of the conversion functions are still
120 pertinent: CFUX and CFUY allow one to convert the X and Y coordinates
121 of a point from the fractional system to the user system, while CUFX
122 and CUFY do the opposite.
123 To use one of these conversion routines, load the NCAR Graphics
125 libraries ncarg, ncarg_gks, and ncarg_c, preferably in that order.
126
128 Online: cfux, cfuy, cmfx, cmfy, cmux, cmuy, cpfx, cpfy, cpux, cpuy,
129 cufx, cufy, kfmx, kfmy, kfpx, kfpy, kmpx, kmpy, kpmx, kpmy, kumx, kumy,
130 kupx, kupy, spps, ncarg_cbind
131 Hardcopy: NCAR Graphics Fundamentals, UNIX Version; User's Guide for
133 NCAR GKS-0A Graphics
134
136 Copyright (C) 1987-2007
137 University Corporation for Atmospheric Research
138 This documentation is free software; you can redistribute it and/or
140 modify it under the terms of the GNU General Public License as
141 published by the Free Software Foundation; either version 2 of the
142 License, or (at your option) any later version.
143 This software is distributed in the hope that it will be useful, but
145 WITHOUT ANY WARRANTY; without even the implied warranty of
146 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
147 General Public License for more details.
148 You should have received a copy of the GNU General Public License along
150 with this software; if not, write to the Free Software Foundation,
151 Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
152UNIX March 1993 SPPS_converters(3NCARG)