ncl_sfwrld man page

SFWRLD — The subroutines SFWRLD and SFNORM are used to fill that portion of the plotter frame inside the area defined by a given polygonal boundary.

Synopsis

CALL SFWRLD (XRA,YRA,NRA,DST,NST,IND,NND)

CALL SFNORM (XRA,YRA,NRA,DST,NST,IND,NND)

C-Binding Synopsis

#include <ncarg/ncargC.h>

void c_sfwrld (float *xra, float *yra, int nra,
float *dst, int nst, int *ind, int nnd)

void c_sfnorm (float *xra, float *yra, int nra,
float *dst, int nst, int *ind, int nnd)

Description

XRA
(an input/output array of type REAL, dimensioned NRA) contains the X coordinates of the points defining the area to be filled, in the user coordinate system (if SFWRLD is called) or in the fractional coordinate system (if SFNORM is called). Upon return from SFWRLD, the contents of XRA will have been converted to the fractional coordinate system.
YRA
(an input/output array of type REAL, dimensioned NRA) contains the Y coordinates of the points defining the area to be filled, in the user coordinate system (if SFWRLD is called) or in the fractional coordinate system (if SFNORM is called). Upon return from SFWRLD, the contents of YRA will have been converted to the fractional coordinate system.
NRA
(an input expression of type INTEGER) is the number of points defining the area to be filled. NRA must be greater than two.
DST(NST)
(a scratch array of type REAL, dimensioned NST or greater) is for use by the fill algorithm.
NST
(an input expression of type INTEGER) is the length of the array DST. It must be greater than or equal to NRA + NIM, where NIM is the largest number of intersection points of any fill line with the boundary lines. To be sure DST is large enough, use NIM = NRA; in practice, NIM rarely needs to be that large. For a convex polygon, for example, NIM = 2 suffices.
IND
(a scratch array of type INTEGER, dimensioned NND or greater) is for use by the fill algorithm.
NND
(an input expression of type INTEGER) is the length of the array IND. It must be greater than or equal to NRA + 2 * NIM, where NIM is as defined above.

C-Binding Description

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

Usage

Both SFWRLD and SFNORM fill the area defined by the points (XRA(I),YRA(I)), for I from 1 to NRA. The lines connecting point 1 to point 2, point 2 to point 3, ..., point NRA-1 to point NRA, and point NRA to point 1 bound the area to be filled. The default values of SOFTFILL's internal parameters cause fill to be done with solid, horizontal lines .00125 normalized-device-coordinate units apart.

Use SFWRLD if the arrays XRA and YRA contain world coordinates. Use SFNORM if XRA and YRA contain normalized device coordinates. Since SFWRLD transforms XRA and YRA from world coordinates to normalized device coordinates, any subsequent calls with those arrays should be to SFNORM (for example, to create a cross-hatched effect).

Examples

Use the ncargex command to see the following relevant examples: cmptit, agex12, cpex01, cpex02, cpex03, sfex01, vvex01, tsoftf, fsfwrld.

Access

To use SFWRLD, SFNORM, c_sfwrld, or c_sfnorm, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c, preferably in that order. in that order.

Messages

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

See Also

Online: softfill, softfill_params, sfgetc, sfgeti, sfgetp, sfgetr, sfsetc, sfseti, sfsetp, sfsetr, sfsgfa, ncarg_cbind

Hardcopy: NCAR Graphics Fundamentals, UNIX Version

Info

March 1993 UNIX NCAR GRAPHICS