Ubuntu Manpage: Polypack - a set of routines allowing polygons to be manipulated in various ways. Each of

NAME

       Polypack - a set of routines allowing polygons to be manipulated in various ways. Each of
       the six principal routines is given a "clip" polygon, a "subject" polygon, and a
       workspace; it operates on the two polygons in some way to create either a derivative
       polygon or a set of trapezoids representing the interior of that derivative polygon and
       then passes these on to a user-specified processing routine.

SYNOPSIS

PPDIPO - generates and returns the boundary of the "difference" polygon, which consists of
all points that are inside the subject polygon but not inside the clip polygon.

PPINPO - generates and returns the boundary of the "intersection" polygon, which consists
of all points that are inside both the clip polygon and the subject polygon.

PPUNPO - generates and returns the boundary of the "union" polygon, which consists of all
points that are inside either or both of the clip polygon and the subject polygon.

PPDITR - generates and returns a set of trapezoids representing the interior of the
"difference" polygon, which consists of all points that are inside the subject polygon but
not inside the clip polygon.

PPINTR - generates and returns a set of trapezoids representing the interior of the
"intersection" polygon, which consists of all points that are inside both the clip polygon
and the subject polygon.

PPUNTR - generates and returns a set of trapezoids representing the interior of the
"union" polygon, which consists of all points that are inside either or both of the clip
polygon and the subject polygon.

PPPPAP - can be called to preprocess a polygon in such a way as to remove certain
peculiarities that can cause minor cosmetic errors in the output from the routines that
return trapezoids.

PPPLCL - clips a polyline against a clipping rectangle. It is intended that, eventually,
there should be a better routine that will clip a polyline against an arbitrary polygon,
but that routine has not yet been written.

C-BINDING SYNOPSIS

       #include <ncarg/ncargC.h>

       c_ppdipo
       c_ppditr
       c_ppinpo
       c_ppintr
       c_ppplcl
       c_ppppap
       c_ppunpo
       c_ppuntr

ACCESS

       To use Polypack routines, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c,
       preferably in that order.

MESSAGES

       None.  All error conditions in Polypack routines are reported by means of an error-flag
       argument.

COPYRIGHT