Full-page screen shot with RSelenium - r

Question

I want to take a screenshot of an entire webpage using RSelenium. I have this code working:
library(RSelenium)
driver <- rsDriver(browser = "firefox")
remdriv <- driver$client
remdriv$navigate("https://stackoverflow.com/questions/73115385/counting-all-elements-row-wise-in-list-column")
remdriv$screenshot(file = "post.png")
But when I run this I get a screenshot of exactly what the driver's browser is showing, like this:
What I want is the full-length screenshot of the entire webpage. What can I do to capture that within RSelenium or another R tool?
In the end I want it to look like this:

Answer 1

I think you have to scroll down and take multiple screenshots, then combine these multiple screenshots into a single one. I haven't managed yet to zoom out yet, which would be another option.
The scrolling doesn't work perfectly and you need to loop and finish up the script, but I hope this is useful to start with:
# Load packages
if (!require(pacman)) {install.packages("pacman")}
pacman::p_load(here, RSelenium, stringr)
# Stop currently running server
if(exists("rD")) suppressWarnings(rD$server$stop())
# Load RSelenium
rD <- rsDriver(browser = "chrome", chromever = "106.0.5249.61", port = 4567L)
remDr <- rD[["client"]]
link <- "https://stackoverflow.com/questions/73115385/counting-all-elements-row-wise-in-list-column"
remDr$open()
remDr$navigate(link)
# Get browser height and width
browser_height <- remDr$executeScript("return document.body.offsetHeight;")[[1]]
browser_width <- remDr$executeScript("return document.body.offsetWidth;")[[1]]
remDr$getWindowSize()
remDr$setWindowSize(browser_width, browser_height)
remDr$getWindowSize()
# This is what actually can be displayed
browser_final_height <- remDr$getWindowSize()$height # 1175
# Get inner window height and width
inner_window_height <- remDr$executeScript("return window.innerHeight")[[1]]
inner_window_width <- remDr$executeScript("return window.innerWidth")[[1]]
# Check how many xtimes the inner window fits in what should be the document size
num_screen <- (browser_height / inner_window_height)
# Move to top of window
remDr$executeScript("window.scrollBy(0, -5000);")
# Scroll down (loop from here to end)
remDr$executeScript(str_c("window.scrollBy(0, ", inner_window_height, ");"))
# Take screenshot
remDr$screenshot(file = here("results", "screenshots", "ex2.png"))
# Close server
remDr$close()
rD$server$stop()