NAME

       ARSCAM - Scans an area map from left to right, extracting the definitions of all the areas
       defined by the area map and delivering them to a user-defined subroutine for processing.

SYNOPSIS

       CALL ARSCAM (MAP,XCS,YCS,MCS,IAI,IAG,MAI,APR)

C-BINDING SYNOPSIS

       #include <ncarg/ncargC.h>

       void c_arscam (int *map, float *xcs, float *ycs, int mcs, int *iai, int *iag, int mai, int
       (*apr)(float *xcs, float *ycs, int *ncs, int *iai, int *iag, int *nai))

DESCRIPTION

       MAP         (an input/output array of type INTEGER) - An array containing an area map that
                   has been initialized by a call to ARINAM and to which edges have been added by
                   calls to AREDAM.  If you did not preprocess the area map by calling ARPRAM,
                   ARSCAM calls it before doing anything else.

                   Note: As part of initializing the area map, ARINAM stores the dimension of MAP
                   in MAP(1); therefore, the dimension does not have to be given as an argument
                   in calls to ARSCAM.)

       XCS,YCS     (workspace arrays, dimensioned MCS, of type REAL) - Hold the X and Y
                   coordinates defining the edge of a given area, for use by ARSCAM in calls to
                   the area-processing routine APR.

       MCS         (an input expression of type INTEGER) - Dimension of each of the arrays XCS
                   and YCS.

       IAI,IAG     (workspace arrays, dimensioned MAI, of type INTEGER) - Hold MAI pairs of area
                   identifiers and group identifiers, respectively. Used by ARSCAM in calls to
                   the area-processing routine APR.

       MAI         (an input expression of type INTEGER) - Dimension of each of the arrays IAI
                   and IAG. MAI must be greater than or equal to n, where n is the number of
                   groups in the area map.

       APR         (a subroutine) - An area-processing routine that is called by ARSCAM, and must
                   be declared EXTERNAL in the routine that calls ARSCAM. You must supply the
                   routine APR, and it must have the following form:

                   SUBROUTINE APR (XCS,YCS,NCS,IAI,IAG,NAI)
                   DIMENSION XCS(*),YCS(*),IAI(*),IAG(*)

                   (code to process the area defined by XCS, YCS, IAI, and IAG)

                   RETURN
                   END

                   XCS,YCS     (input arrays, dimensioned NCS, of type REAL) - The X and Y
                               coordinates, in NDCs, of NCS points defining a polygonal area. The
                               last of these points is a duplicate of the first. Holes in an area
                               are traced in a way that maximizes the probability of hardware
                               fill working properly.

                   NCS         (an input expression of type INTEGER) - Number of X and Y
                               coordinates in the arrays XCS and YCS.

                   IAI,IAG     (input arrays, dimensioned NAI, of type INTEGER) - Hold NAI pairs
                               of identifiers for the area defined by XCS and YCS. For each value
                               of I from 1 to NAI, IAI(I) is the area identifier for the area
                               with respect to the group of edges specified by the group
                               identifier IAG(I).

                   NAI         (an input expression of type INTEGER) - Number of values returned
                               in IAI and IAG. NAI equals the number of groups of edges that you
                               put in the area map.

       Before executing the first call to APR, ARSCAM calls GETSET to retrieve the current user
       coordinates and then executes the statement:

       CALL SET (VPL,VPR,VPB,VPT,VPL,VPR,VPB,VPT,1)

       where VPL, VPR, VPB, and VPT are the viewport left, right, bottom, and top coordinates in
       NDCs.

       This ensures correct results if the NDCs in XCS and YCS are used in calls to such routines
       as GFA and GPL, and it allows clipping at the edges of the viewport. APR may make its own
       SET call to achieve some other effect. Before returning control to the calling routine,
       ARSCAM calls SET again to restore the original mapping parameters.

C-BINDING DESCRIPTION

       The C-binding argument descriptions are the same as the FORTRAN argument descriptions.

EXAMPLES

       Use the ncargex command to see the following relevant examples: cardb1, carfill, ccpcldm,
       ccpfil, ccplbam, ccpllb, ccplll, ccpllw, ccpscam, ccpvs, colcon, cmpfil, cmpgrp, cmpita,
       cmptit, cpex01, cpex02, cpex03, cpex04, cpex05, cpex07, cpex08, eezmpa, arex01, vvex01,
       tareas, tconpa, tezmpa, fcover, ffex00, fcirc, fsfsgfa, fsppoint.

ACCESS

       To use ARSCAM or c_arscam, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c,
       preferably in that order.

MESSAGES

       See the areas man page for a description of all Areas error messages and/or informational
       messages.

SEE ALSO

       Online: areas, areas_params, ardbpa, ardrln, aredam, argeti, argetr, argtai, arinam,
       armvam, arpram, arseti, arsetr, ncarg_cbind

       Hardcopy: NCAR Graphics Contouring and Mapping Tutorial

COPYRIGHT

       Copyright (C) 1987-2009
       University Corporation for Atmospheric Research
       The use of this Software is governed by a License Agreement.