Saving gvisGeoMap object to png

Question

How can I save a gvis object from googleVis to png? ggvis has export_png but that doesn't work for googleVis.

I saw several asking this but is there really no way?

test_data <- data.frame(count=c(1,2,5),group=c("Australia","Austria","China"))

p <- gvisGeoMap(test_data,locationvar='group',numvar='count',options=list(dataMode='regions',colors="['0x0000ff', '0xff0000']"))

plot(p)

Answer 1

There are many ways to proceed with this with unpredictable results. Some of the tricks:

1. Xvfb, imagemagick and browser.

   You need to have all three of them installed. This won't work on Windows. I am assuming you have install xvfb and imagemagick. You start xvfb server in shell:-

   Xvfb :3 -screen 0 1024x768x24 &
   

   Now in R, you can print the file as html:

   print(p, file="p.html")
   

   Now a system call:

   system("DISPLAY=:3      firefox     g1.html  &")
   

   Now print the file using:

   system("DISPLAY=:3 import -window root p.png")
   

   You will get the file as p.png. You can use some other browser also like chrome.

2. Using wkhtmltopdf package.

   After installing wkhtmltopdf and having it in your PATH, use system call:

   print(p, file="p.html")
   system("wkhtmltoimage --enable-plugins --javascript-delay 10000   p.html p.png")
   

   Results aren't predictable. Sometime flash doesn't work. Sometime it works for some platform. I couldn't reproduce like my first solution. (For OP, this solution worked. This is a cross platform solution.)

3. As shiny app, phantomjs and webshot:

   Assuming you have printed the file that I have given, create a shiny app using following methods:

   mkdir app # Create App Directory
   # Create UI
   cat <<- EOF > app/ui.R
   library(shiny)
   
   shinyUI(fluidPage(
     titlePanel("Google Chart"),
     mainPanel(
       includeHTML("../g1.html")
     )
   ))    
   EOF
   # Create server
   cat <<- EOF > app/server.R
   library(shiny)
   shinyServer(function(input, output) {
   })
   EOF
   

   Now install phantomjs:

   npm install -g phantomjs
   

   In r:-

   install.packages("webshot")
   appshot("app", "p.png")
   

   You will see that you won't get flash charts because phantomjs now doesn't support flash. So this method too is limited. Only first method will work but it's not cross platform. But you can proceed with that approach in windows by using equivalent stuff.

Answer 2

As of now, webshot2 is available. I posted my solution here.