cant get webshot2 to create a png of a local html file

Question

I want to include my highchart plots and leaflet map in a pdf file (or docx).

Maybe there is a way simpler way than this here.

I have a test app running on shiny-server that works just fine. webshot2 creates a png and that png will get included in the tex file and then converted to pdf.:

library(shiny)
library(webshot2)
library(tinytex)


ui <- fluidPage(
  titlePanel("Wikipedia Screenshot to PDF"),
  sidebarLayout(
    sidebarPanel(
      downloadButton("downloadPDF", "Download PDF")
    ),
    mainPanel(
     
    )
  )
)
server <- function(input, output, session) {
  
  output$downloadPDF <- downloadHandler(
    filename = function() {
      "WikipediaScreenshot.pdf"
    },
    content = function(file) {
      
      webshot2::webshot(url = "https://example.com/", 
                        file = "example.png")
      
      
      tex_file <- "temp.tex"
      tex_content <- paste(
        "\\documentclass{article}",
        "\\usepackage{graphicx}",
        "\\begin{document}",
        "\\includegraphics[width=\\textwidth]{wikipedia.png}",
        "\\end{document}",
        sep = "\n"
      )
      writeLines(tex_content, tex_file)
      tinytex::pdflatex(tex_file)
      
      
      file.copy("temp.pdf", file)
      file.remove("temp.pdf")
    },
    contentType = "application/pdf"
  )
}
shinyApp(ui, server)

The main difference in my main app is, that i am using a local html file instead of a url for webshot2::webshot(). those htmls are the capture of the highcharter plot and leaflet map, and get created just fine.

But the png that get created from webshot are just blank. i tried to delay the capture but it makes no difference. all png created will also have the same size.

  output$downloadReport <- downloadHandler(
    filename = function() {
      "ComplexAppReport.pdf"
    },
    content = function(file) {

      # Save Highcharts to HTML
  htmlwidgets::saveWidget(value_bar_chart(), "value_bar_chart.html")
  htmlwidgets::saveWidget(value_bar_chart2(), "value_bar_chart2.html")

  # Save Leaflet maps to HTML
  mapshot(leaflet_map1(), url  = "leaflet_map1.html")
  mapshot(leaflet_map2(), url = "leaflet_map2.html")

     
      print(file.exists("value_bar_chart.html"))
      print(file.exists("leaflet_map1.html"))

      #HTML to PNG
      webshot2::webshot(url="/srv/shiny-server/dashboard/value_bar_chart.html", file = "value_bar_chart.png")
      webshot2::webshot(url="/srv/shiny-server/dashboard/value_bar_chart2.html",file = "value_bar_chart2.png")
      webshot2::webshot(url="/srv/shiny-server/dashboard/leaflet_map1.html",file = "leaflet_map1.png")
      webshot2::webshot(url="/srv/shiny-server/dashboard/leaflet_map2.html", file ="leaflet_map2.png")

      
      tex_file <- "temp.tex"
      tex_content <- paste(
        "\\documentclass{article}",
        "\\usepackage{graphicx}",
        "\\begin{document}",
        "\\includegraphics[width=0.8\\textwidth]{value_bar_chart.png}",
        "\\includegraphics[width=0.8\\textwidth]{value_bar_chart2.png}",
        "\\includegraphics[width=0.8\\textwidth]{leaflet_map1.png}",
        "\\includegraphics[width=0.8\\textwidth]{leaflet_map2.png}",
        "\\end{document}",
        sep = "\n"
      )
      writeLines(tex_content, tex_file)
      tinytex::pdflatex(tex_file)

     
      file.copy("temp.pdf", file)
      file.remove("temp.pdf")
    },
    contentType = "application/pdf"
  )

Or is there another way that i can get my highchart plots and leaflet map into a pdf or docx?

Thanks so much for the help.

Answer 1

You could include the leaflet map and highcharter plots in a quarto document (RMarkdown should work, too).

Make sure that PhantomJS is installed (webshot::install_phantomjs()).

Here is an example file:

---
title: "Leaflet & Highcharter to docx"
format: docx
editor: visual
---

```{r}
library(leaflet)
library(highcharter)
```

```{r}
hchart(
  iris,
  "scatter",
  hcaes(x = Sepal.Length, y = Sepal.Width, group = Species)
)
```

```{r}
m <- leaflet() %>%
  addTiles() %>%  # Add default OpenStreetMap map tiles
  addMarkers(lng=174.768, lat=-36.852, popup="The birthplace of R")
m
```

Alternatively use pagedown::chrome_print() to turn any HTML file into a pdf:

pagedown::chrome_print("value_bar_chart.html")

Answer 2

thanks so much.

pagedown::chrome_print() 

did the trick.

created a pdf for each html and merged them into a final pdf at the end.

webshot wasnt working for me. i think my relative path was wrong for my local html. here is the last version i tried using webshot2::webshot()

      webshot2::webshot(url = "file:///srv/shiny-server/dashboard/www/value_bar_chart.html",
                    file = "/srv/shiny-server/dashboard/www/value_bar_chart.png",
                    delay = 2)