png tests on Linux

pngtest.r

# On ubuntu, this is needed to compile Cairo:
# sudo apt-get install libcairo2-dev 
# sudo apt-get install libxt-dev 

# install.packages('Cairo')

library(ggplot2)

# Regular png
png('test1-png.png')
ggplot(mtcars, aes(wt, mpg)) + geom_point()
dev.off()

# png, attempting to use cairo device
png('test2-cairo.png', type="cairo")
ggplot(mtcars, aes(wt, mpg)) + geom_point()
dev.off()

# With Cario library
library(Cairo)
CairoPNG('test3-CairoPNG.png')
ggplot(mtcars, aes(wt, mpg)) + geom_point()
dev.off()
# This successfully antialiases points

test1-png.png

test2-cairo.png

test3-CairoPNG.png