ncl_spps_converters(3)

1SPPS_converters(3NCARG)          NCAR GRAPHICS         SPPS_converters(3NCARG)
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NAME

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.
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STATUS

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.
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18       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
24       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:
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28       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.
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34       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.
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SYNOPSIS

41       Current:
42       X = CFUX (RX),  Y = CFUY(RY)
43       X = CUFX (RX),  Y = CUFY(RY)
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45       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)
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C-BINDING SYNOPSIS

58       #include <ncarg/ncargC.h>
59
60       float c_cfux (float rx)
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62       float c_cfuy (float ry)
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64       float c_cufx (float rx)
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66       float c_cufy (float ry)
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DESCRIPTION

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.
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75       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.
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81       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
86       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.
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91       The second letter of the function name specifies the coordinate system
92       of the argument.
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94       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.
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99       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.
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C-BINDING DESCRIPTION

103       The C-binding argument description is the same as the FORTRAN argument
104       description.
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EXAMPLES

107       Use the ncargex command to see the following relevant examples which
108       use coordinate converters: mpex10, cbex01, sfex02, epltch.
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110       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.
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ACCESS

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
124       To use one of these conversion routines, load the NCAR Graphics
125       libraries ncarg, ncarg_gks, and ncarg_c, preferably in that order.
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COPYRIGHT

136       Copyright (C) 1987-2009
137       University Corporation for Atmospheric Research
138       The use of this Software is governed by a License Agreement.
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142UNIX                              March 1993           SPPS_converters(3NCARG)