Name: PGPOLY Purpose: draw a polygon, using fill-area attributes Category: GRAPHICS File: pgplot.src Author: T.J. Pearson Use: see description below. Description: SUBROUTINE PGPOLY (N, XPTS, YPTS) INTEGER N REAL XPTS(*), YPTS(*) Fill-area primitive routine: shade the interior of a closed polygon in the current window. The action of this routine depends on the setting of the Fill-Area Style attribute (see PGSFS). The polygon is clipped at the edge of the window. The pen position is changed to (XPTS(1),YPTS(1)) in world coordinates (if N > 1). If the polygon is not convex, a point is assumed to lie inside the polygon if a straight line drawn to infinity intersects and odd number of the polygon's edges. Arguments: N (input) : number of points defining the polygon; the line consists of N straight-line segments, joining points 1 to 2, 2 to 3,... N-1 to N, N to 1. N should be greater than 2 (if it is 2 or less, nothing will be drawn). XPTS (input) : world x-coordinates of the vertices. YPTS (input) : world y-coordinates of the vertices. Note: the dimension of arrays XPTS and YPTS must be greater than or equal to N. Updates: Oct 16, 1998: JPT automatically extracted from source.