antipolygon: Colour everything outside a given polygon.

In adeckmyn/meteogrid: Gridded meteorological data

Colour everything outside a given polygon.

Description

This routine does the inverse of 'polygon': it colours everything outside a given polygnon. This may be useful for e.g. blanking out a plot outside certain borders. This routine is quite simple and may not work under all circumstances.

Usage

antipolygon(data,xylim=DomainExtent(.Last.domain()), bg='white')

Arguments

data	A polygon (x and y columns).
bg	Colour to use.
xylim	Boundaries for the 'antipolygon'. Usually the boundaries of the presentt plot.

Details

antipolygon() works by adding the 4 corner points to the polygon, thus 'inverting' it.

See Also

limage,vecplot

Examples

 ## Not run: 
mask <- project(map("world","Belgium",fill=0,plot=FALSE))
xylim <- DomainExtent(datafield)
antipolygon(mask,xylim=xylim)

## End(Not run) 

adeckmyn/meteogrid documentation built on Jan. 13, 2025, 11:02 p.m.