PK_PLINE_sf_t

struct PK_PLINE_sf_s
    {
    int          n_positions;
    PK_VECTOR_t *positions;
    PK_LOGICAL_t closed;
    double       base_parameter;
    };

typedef struct PK_PLINE_sf_s PK_PLINE_sf_t;


This datatype is the standard form of a pline (polyline).

Used in:

PK_PLINE_ask
PK_PLINE_create

The polyline is parameterised by the value of 'base_parameter' plus the
cumulative chord length along the polyline.

The standard form has the fields:

'n_positions'      The number of elements in the 'positions' array.

'positions'        This is an array of vectors that contains the positions of
                   the points defining the polyline.

'closed'           This field is set to PK_LOGICAL_true if the polyline is
                   closed. Any closed polyline is deemed to have a periodic
                   parameterisation. The position vector which would close
                   the polyline should not be included in 'n_positions' and
                   'positions'.

'base_parameter'   This field contains the parameter value of the curve at
                   `positions[0]'.