Clipping is the process of removing part of one polygon when two polygons
intersect. For example, in a block map, a block might overlap the
boundary of its map area. In this case, the polygon that makes up
the map area is clipped so that you do not see the boundary line behind
the block. (See Intersecting Polygons for an illustration of a clipped polygon.) The type of
clipping used by a graph affects whether a clipped area can use hardware
patterns.
POLYGONCLIP is affected
by the PCLIP graphics option:
POLYGONCLIP with PCLIP or NOPCLIP
all areas can use hardware
patterns
NOPOLYGONCLIP with NOPCLIP
all areas use only
software patterns
areas can use either
hardware or software patterns depending on the nature of the clipped
polygons.
Under some conditions
the polygons might not be clipped correctly. Specifying both POLYGONCLIP
and NOPCLIP will produce the correct graph.