CREATE OR REPLACE FUNCTION test.plot()
RETURNS void LANGUAGE plr IMMUTABLE AS
$$
# e.g.
# SELECT test.plot();

lab = paste(collapse='\n', c(
    'PostgreSQL 9.5dev',
    'and PL/R 8.13.0.6',
    '',
    'on CentOS 6.6'))

png('Rplots.png')
par(lheight=1.4)
n = 100
plot(
    cex=runif(n) * 10,
    col=adjustcolor(topo.colors(n), 0.15),
    pch=16,
    x=runif(n), y=runif(n),
    xlim=0:1, ylim=0:1)
text(
    cex=2,
    font=2,
    label=lab,
    x=0.5, y=0.5)
graphics.off()
$$;

SELECT test.plot();