I want to see find the base64 encoding of an image, so I can save a plot as part of a JSON file or embedded into an HTML page.
library(party)
irisct <- ctree(Species ~ ., data = iris)
plot(irisct, type="simple")
Are there other ways to share an R image over the web?
I don't know exactly what you want to accomplish, but here is an example:
# save example plot to file
png(tf1 <- tempfile(fileext = ".png")); plot(0); dev.off()
# Base64-encode file
library(RCurl)
txt <- base64Encode(readBin(tf1, "raw", file.info(tf1)[1, "size"]), "txt")
# Create inline image, save & open html file in browser
html <- sprintf('<html><body><img src="data:image/png;base64,%s"></body></html>', txt)
cat(html, file = tf2 <- tempfile(fileext = ".html"))
browseURL(tf2)
You could try using knitr
library(knitr)
printImageURI<-function(file){
uri=image_uri(file)
file.remove(file)
cat(sprintf("<img src=\"%s\" />\n", uri))
}
the printImageURI function takes the filename of a file on disk (I use it quite often with PNG files generated by ggplot). It works great with Firefox, Chrome and IE.
If you have the package base64enc installed, it's much simpler, with equivalent results (assuming you have the image file.png already on disk):
# Using RCurl:
txt1 <- RCurl::base64Encode(readBin("file.png", "raw", file.info("file.png")[1, "size"]), "txt")
# Using base64encode:
txt2 <- base64enc::base64encode("file.png")
html1 <- sprintf('<html><body><img src="data:image/png;base64,%s"></body></html>', txt1)
html2 <- sprintf('<html><body><img src="data:image/png;base64,%s"></body></html>', txt2)
# This returns TRUE:
identical(html1, html2)
But using knitr::image_uri("file.png") (see Bert Neef's answer) is even simpler!
