How to save Leaflet in R map as png or jpg file?

Question

I'm using Leaflet package to create maps in R. It works perfectly. I can export maps in R with simply Export, but I need to export maps from script in R. My simple code is:

png("test_png.png")
(m <- leaflet() %>% addTiles())
dev.off()

It works but... the output png file is white blank.

Answer 1

This very nice workaround emerged in response to a question asked a little later here on SO. Note that you are required to install PhantomJS to get the following code to work.

## install 'webshot' package
library(devtools)
install_github("wch/webshot")

## load packages
library(leaflet)
library(htmlwidgets)
library(webshot)

## create map
m <- leaflet() %>% addTiles()

## save html to png
saveWidget(m, "temp.html", selfcontained = FALSE)
webshot("temp.html", file = "Rplot.png",
        cliprect = "viewport")

And here's the resulting image.

---

Update:

Now that webshot has been officially released on CRAN and with the introduction of mapshot in the mapview package, this manual workaround is no longer required. Now, the code simply goes like this:

library(mapview)

## 'leaflet' objects (image above)
m <- leaflet() %>% addTiles()
mapshot(m, file = "~/Rplot.png")

## 'mapview' objects (image below)
m2 <- mapview(breweries91)
mapshot(m2, file = "~/breweries.png")