CPUY(3NCARG)

💖 CPUY(3NCARG) — NCAR GRAPHICS 💖

okay bestie, welcome to the CPUY page from the NCAR GRAPHICS manual ✨ this one's a coordinate-converter situation and it comes bundled with its whole little family, SPPS_converters(3NCARG), so buckle up 🎀

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🌸 NAME 🌸

CPUY — converts from plotter address unit coordinates to user coordinates.

and also, because this page is a two-for-one deal:

spps_converters — a whole set of functions, each of which transforms a coordinate from one of the NCAR Graphics coordinate systems to another. the complete list of functions is, and I quote, literally this: CFUX, CFUY, CMFX, CMFY, CMUX, CMUY, CPFX, CPFY, CPUX, CPUY, CUFX, CUFY, KFMX, KFMY, KFPX, KFPY, KMPX, KMPY, KPMX, KPMY, KUMX, KUMY, KUPX, and KUPY. 💅

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💀 STATUS 💀

ngl this is the part where you find out half of these are giving ✨ vintage ✨ in the "we don't do that anymore" way.

Plotter Address Units (PAUs) and Metacode Units (MUs) are no longer used in NCAR Graphics; thus, all functions with either an M or a P as the second or third letter of the function name are considered obsolete. 🫠

The current recognized coordinate systems are:

• GKS world coordinates
• GKS normalized device coordinates
• NCAR Graphics fractional coordinates
• NCAR Graphics user coordinates

See the NCAR Graphics document NCAR Graphics Fundamentals, UNIX Version for descriptions of these coordinate systems. 📚

The following definitions of the PAU coordinate system and the MU coordinate system are provided for the purpose of interpreting and converting codes which use PAUs or MUs:

• The plotter coordinates of a point are integers IPX and IPY, where IPX is between 1 and 2**MX and IPY is between 1 and 2**MY. MX and MY are internal parameters of SPPS; each has a default value of 10. Values of MX and MY can be set by calling the routines SETI or SETUSV and retrieved by calling the routines GETSI or GETUSV.
• The metacode coordinates of a point are integers IMX and IMY between 0 and 32767 inclusive. The area addressed is a square in a "metacode space" that is usually mapped into a square subset of the addressable area of the plotting device. Metacode coordinates were used in calls to the routine PLOTIT and are returned in calls to FL2INT.

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✨ SYNOPSIS ✨

Current (the ones that actually still slay):

X = CFUX (RX),  Y = CFUY(RY)
X = CUFX (RX),  Y = CUFY(RY)

Obsolete (respectfully, these are the ancestors 🪦):

X = CMUX (IX),  Y = CMUY(IY)
X = CPUX (IX),  Y = CPUY(IY)
X = CMFX (IX),  Y = CMFY(IY)
X = CPFX (IX),  Y = CPFY(IY)
I = KFMX (RX),  J = KFMY(RY)
I = KUMX (RX),  J = KUMY(RY)
I = KFPX (RX),  J = KFPY(RY)
I = KUPX (RX),  J = KUPY(RY)
I = KPMX (IX),  J = KPMY(IY)
I = KMPX (IX),  J = KMPY(IY)

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🦋 C-BINDING SYNOPSIS 🦋

#include <ncarg/ncargC.h>

float c_cfux (float rx)

float c_cfuy (float ry)

float c_cufx (float rx)

float c_cufy (float ry)

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💜 DESCRIPTION 💜

okay so here's how the naming scheme works, and honestly it's giving cryptic-cipher-but-make-it-elegant 🔥

• RX — an input expression of type REAL, and it's an X coordinate in the coordinate system specified by the second letter of the function name. In a reference to CFUX, RX is a fractional X coordinate; in a reference to CUFX, RX is a user X coordinate.
• RY — an input expression of type REAL, and it's a Y coordinate in the coordinate system specified by the second letter of the function name. In a reference to CFUY, RY is a fractional Y coordinate; in a reference to CUFY, RY is a user Y coordinate.
• IX and IY occur as arguments only in references to some of the obsolete functions; they represent input expressions of type INTEGER, specifying the X and Y coordinates of a point in either PAUs or MUs (depending on the second letter of the function name).
• The first letter of the function name is a C if the result is of type REAL and a K if the result is of type INTEGER (the latter only happens for some of the obsolete ones). This conforms to the usual FORTRAN convention for implicit typing.
• The second letter of the function name specifies the coordinate system of the argument.
• The third letter of the function name specifies the coordinate system of the functional result. In references to CFUX and CFUY, the result is in the user system; in references to CUFX and CUFY, the result is in the fractional system.
• The fourth letter of the function name is an X or a Y, depending on whether an X or a Y coordinate is being converted.

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🌈 C-BINDING DESCRIPTION 🌈

The C-binding argument description is the same as the FORTRAN argument description. no notes, it's just identical, periodt 💅

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🎀 EXAMPLES 🎀

Use the ncargex command to see the following relevant examples which use coordinate converters: mpex10, cbex10, sfex02, epltch.

The command "ncargex -n mpex10" will load the driver mpex10.f into your current working directory where you can examine the file using a local editor, or the UNIX more command. go peek bestie, it's right there 👀

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👑 ACCESS 👑

There were 24 conversion functions in the original set. These functions (12 for the X coordinate of a point, and 12 for the Y coordinate), allowed one to convert between any combination of PAUs, MUs, fractional coordinates, and user coordinates. PAUs and MUs are now obsolete; thus, only four of the conversion functions are still pertinent: CFUX and CFUY allow one to convert the X and Y coordinates of a point from the fractional system to the user system, while CUFX and CUFY do the opposite. ✨ 24 in, 4 standing, that's the vibe check ✨

To use any of the conversion routines, load the load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c, preferably in that order. (yes, the original really does say "load the load the" — I'm keeping it, character for character, that's canon 🫶)

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🧚 SEE ALSO 🧚

• Online: cfux, cfuy, cmfx, cmfy, cmux, cmuy, cpfx, cpfy, cpux, cpuy, cufx, cufy, kfmx, kfmy, kfpx, kfpy, kmpx, kmpy, kpmx, kpmy, kumx, kumy, kupx, kupy, spps, ncarg_cbind
• Hardcopy: NCAR Graphics Fundamentals, UNIX Version; User's Guide for NCAR GKS-0A Graphics

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💖 COPYRIGHT 💖

Copyright (C) 1987-2009 University Corporation for Atmospheric Research

The use of this Software is governed by a License Agreement.

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and that's the whole page, bestie 🥹 the version of this one is SPPS_converters(3NCARG), it came out of the UNIX manual, and it's dated March 1993 — so if you're reading this, you're reading certified vintage NCAR lore 🎀💫 slay, bye 💅