If the figure is resized after plotting, filling may not appear correct.
See Also
polygon, par
Examples
set.seed(2018)x = runif(100)y = runif(100)######### some data points to plot:plot(x,y)########### create polygon:pp =list(x=c(0.231,0.316,0.169,0.343,0.311,0.484,0.757,0.555,0.800,0.563,0.427,0.412,0.203), y=c(0.774,0.622,0.401,0.386,0.138,0.312,0.200,0.459,0.658,0.624,0.954,0.686,0.813))polygon(pp)antipolygon(x=pp$x, y=pp$y,col='blue')#### where as this does not look so goodplot(x,y)antipolygon(x=pp$x, y=pp$y,col='blue', corner=2)