MPCHLN(3NCARG)

💖 MPCHLN — the boundary-line glow-up routine 💖

okay bestie, welcome to the NCAR GRAPHICS corner of the manual pages, this one's MPCHLN(3NCARG) and she is literally the little hook that lets you touch every boundary line as it goes by. 🦋

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✨ NAME ✨

MPCHLN — this routine gets called over and over again while boundary lines are being processed by MPLNAM, MPLNDM, and MPLNDR. The default version of the routine? Does absolutely nothing, she's just vibing. But a user-supplied version may take action to change various characteristics of the lines. that's the whole point, that's the assignment. 💅

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✨ SYNOPSIS ✨

CALL MPCHLN (IACT,ILTY,IOAL,IOAR,NPTS,PNTS)

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✨ C-BINDING SYNOPSIS ✨

None. 💀 (that's it. that's the section. no C binding here, bestie.)

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✨ DESCRIPTION ✨

• IACT — an input expression of type INTEGER, and she's the one who tells you which of the EZMAPB routines called MPCHLN and what that routine is doing or has done with the boundary line defined by the arguments NPTS and PNTS. Here's the tea: IACT is positive if the line is about to be processed, negative if the line was just processed. And its absolute value? That's your caller ID: 1 if the call comes from MPLNAM (which puts lines into an area map), 2 if the call comes from MPLNDM (which draws lines masked by some area map), and 3 if the call comes from MPLNDR (which just draws lines). 🎀
• ILTY — an input expression of type INTEGER, and she specifies the type of the line, so let's run the vibe check:
  • 1 => a line separating land from water 🌊
  • 2 => a line separating one "continent" from another (as, for example, Africa from Eurasia, North America from Central America, or Central America from South America) 🌎
  • 3 => a line separating one country from another 🗺️
  • 4 => a line separating one state from another 📍
  • 5 => a line separating one county from another 🧭
• IOAL and IOAR — input/output variables of type INTEGER, and they are the identifiers of the areas to the left and right, respectively, of the line. (Left and right are defined from the standpoint of a viewer standing at point 1 of the line and looking toward point 2 — so like, imagine you're standing there, that's the whole deal.) The values of IOAL and IOAR may be changed by a knowledgeable user. 👑
• NPTS — an input/output variable of type INTEGER, and on entry she is the number of points defining the line. NPTS may be zeroed by MPCHLN to suppress any use of the line by the calling routine. (zero her out and the line simply does not happen, iconic.) 🙈
• PNTS — an input/output array, dimensioned 2*NPTS, of type REAL, and she's an array of point coordinates. So: PNTS(1) and PNTS(2) are the latitude and longitude of the first point, PNTS(3) and PNTS(4) the latitude and longitude of the second point, ... and PNTS(2*NPTS-1) and PNTS(2*NPTS) the latitude and longitude of the last point. All values are in degrees. Longitudes are all between -180 and +180; no segment crosses the meridian at -180 (+180) degrees. ⭐

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✨ C-BINDING DESCRIPTION ✨

The C-binding argument description is the same as the FORTRAN argument description. fr fr, same thing, no notes. 💜

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✨ USAGE ✨

So here's how she moves: MPCHLN is called by each of the routines MPLNAM, MPLNDM, and MPLNDR just before and just after the processing of each boundary line read from a specified map database. 🌀

A user-supplied version may take action to change various characteristics of the lines. For example:

• the area identifiers to be used for the line can be changed
• the line can be deleted entirely
• and line styles, colors, and widths can be set

like, that's a whole glow-up pipeline, bestie. 💅✨

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✨ EXAMPLES ✨

Use the ncargex command to see the following relevant example: mpex11. go look, it's right there. 🍓

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✨ ACCESS ✨

To use the default version of MPCHLN, load the NCAR Graphics libraries ncarg, and ncarg_gks, preferably in that order. (order matters, don't be chaotic.) 🧚

To supply your own version, just compile it and load it. that's it. main character energy. 👑

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✨ SEE ALSO ✨

Online: ezmap, ezmap_params, mapaci, mapbla, mapblm, mapdrw, mapeod, mapfst, mapgci, mapgrd, mapgrm, mapgtc, mapgti, mapgtl, mapgtr, mapint, mapiq, mapiqa, mapiqd, mapiqm, mapit, mapita, mapitd, mapitm, maplbl, maplmb, maplot, mappos, maproj, maprs, maprst, mapsav, mapset, mapstc, mapsti, mapstl, mapstr, maptra, maptri, maptrn, mapusr, mapvec, mpfnme, mpgetc, mpgeti, mpgetl, mpgetr, mpglty, mpiaty, mpifnb, mpilnb, mpiola, mpiosa, mpipai, mpipan, mpipar, mpisci, mplnam, mplndm, mplndr, mplnri, mpname, mprset, mpsetc, mpseti, mpsetl, mpsetr, supmap, supcon, ncarg_cbind

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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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💖 okay that's the whole page, bestie. go forth and process those boundary lines. no cap. 💖

this one came from the UNIX manual pages, dated April 1998, page MPCHLN(3NCARG) — mwah, love her, bye. 🌈🎀💅