R function to export Plotly graphs as static SVG (and optionally PDF and PNG) images.

export_plotly2SVG.R

# Remarks:
#
# The export is done using the automated testing framework [Selenium](https://
# de.wikipedia.org/wiki/Selenium) which results in opening a browser window
# (Google Chrome) that might has to be closed by hand. Other than Plotly's
# own `export()` function this one also allows to set the `width` and `height`
# of the exported plot (in the former it's hardcoded to 800x600 pixels). If
# `incl_PDF_copy`/`incl_PNG_copy` is set to `TRUE`, the exported SVG additionally
# gets converted to a PDF/PNG using the R package [`rsvg`](https://github.com/
# jeroen/rsvg/tree/40576ac326621b40224db344b09158f4ff717433) which relies on
# [`librsvg`](https://de.wikipedia.org/wiki/Librsvg). On Linux distributions
# the development package of `librsvg` must be installed. On macOS the required
# dependency (`librsvg`) can be installed using [Homebrew](https://brew.sh/).
# Optional PNG auto-cropping is done using the `imager` R package.

ensure_package <- Vectorize(
  FUN =
    function(package,
             load = TRUE)
    {
      installed_packages <- rownames(installed.packages())
      
      if ( !(package %in% installed_packages) )
      {
        install.packages(package,
                         repos = "https://cloud.r-project.org/")
      }
      if ( load ) library(package, character.only = TRUE)
    }
)

export_plotly2SVG <- function(plotly_graph,
                              filename = NULL,
                              parent_path = paste0(getwd(), "/output"),
                              width = 800,
                              height = 600,
                              remove_title = FALSE,
                              font_family = "Arial",
                              incl_PDF_copy = FALSE,
                              incl_PNG_copy = FALSE,
                              png_scaling_factor = 1.8,
                              autocrop_png = TRUE)
{
  ensure_package(package = c("dplyr",
                             "plotly",
                             "readr",
                             "RSelenium",
                             "rsvg",
                             "stringr"),
                 load = FALSE)
  
  ensure_package("magrittr")
  
  # remove trailing slash in `parent_path`
  parent_path %<>% normalizePath()
  
  # ensure `parent_path` exists
  if ( !dir.exists(parent_path) ) dir.create(path = parent_path,
                                             recursive = TRUE)
  
  # generate sensible filename
  if ( is.null(filename) )
  {
    auto_name <- deparse(substitute(plotly_graph))
    
    filename <- dplyr::if_else(
      condition = auto_name == ".",
      true = "plotly_graph.svg",
      false = paste0(deparse(substitute(plotly_graph)), ".svg")
    )
  } else
  {
    filename %<>%
      stringr::str_replace(pattern = "([^\\.svg])$", 
                           replacement = "\\1.svg")
  }
  
  filepath <- paste0(parent_path, "/", filename)
  
  # delete old SVG file
  if ( file.exists(filepath) )
  {
    unlink(x = filepath)
  }
  
  if ( remove_title )
  {
    plotly_graph %<>%
      plotly::layout(title = "",
                     margin = list(t = 0))
  }
  
  if ( !is.null(font_family) )
  {
    plotly_graph %<>%
      plotly::layout(font = list(family = font_family))
  }
  
  # temporarily export plot to a HTML file
  tempfile <- tempfile(pattern = "plotly_temp_",
                       tmpdir = parent_path,
                       fileext = ".html")
  
  export_plotly2HTML(plotly_graph = plotly_graph,
                     filename = basename(tempfile),
                     parent_path = parent_path)
  
  on.exit(unlink(tempfile),
          add = TRUE)
  
  # get <div> ID of exported htmlwidget
  htmlwidget_id <-
    stringr::str_extract(string = readr::read_file(file = tempfile),
                         pattern = "(?<=<div id=\")htmlwidget-[^\"]+")
  
  # initialize Chrome as RSelenium driver
  selenium_driver <-
    RSelenium::rsDriver(browser = "chrome",
                        extraCapabilities = list(
                          chromeOptions = list(
                            prefs = list(
                              "profile.default_content_settings.popups" = 0L,
                              "download.prompt_for_download" = FALSE,
                              "download.default_directory" = parent_path
                            )
                          )
                        ),
                        verbose = FALSE)
  
  # navigate to temporary HTML file
  selenium_driver$client$navigate(url = paste0("file://", normalizePath(tempfile)))
  
  # download plot as SVG using the native
  # [`Plotly.downloadImage`](https://plot.ly/javascript/plotlyjs-function-reference/#plotlydownloadimage) function
  selenium_driver$client$executeScript(
    script = paste0("Plotly.downloadImage(document.getElementById('", htmlwidget_id, "'), ",
                    "{format: 'svg', width: ", width, ", height: ", height, ", filename: '",
                    tools::file_path_sans_ext(x = filename), "'});"),
    args = list(NULL)
  )
  
  # wait for SVG to be saved to disk
  Sys.sleep(time = 1)
  
  # convert to PDF
  if ( incl_PDF_copy )
  {
    rsvg::rsvg_pdf(svg = filepath,
                   file = paste0(tools::file_path_sans_ext(parent_path), ".pdf"))
  }
  
  # convert to PNG
  if ( incl_PNG_copy )
  {
    filepath_png <- paste0(tools::file_path_sans_ext(parent_path), ".png")
    
    rsvg::rsvg_png(svg = filepath,
                   file = filepath_png,
                   width = png_scaling_factor * width,
                   height = png_scaling_factor * height)
    
    if ( autocrop_png ) autocrop_png(path_to_png = filepath_png)
  }
}

export_plotly2HTML <- function(plotly_graph,
                               filename = NULL,
                               parent_path = paste0(getwd(), "/output"),
                               selfcontained = FALSE,
                               libdir = "plotly_files",
                               disable_legend_toggling = NULL,
                               # you can provide a link to webfonts to be used like this:
                               # add_web_font = "https://fonts.googleapis.com/css?family=Work+Sans:200,300,400,600,700"
                               add_web_font = NULL)
{
  ensure_package(package = c("checkmate",
                             "dplyr",
                             "readr",
                             "stringr"),
                 load = FALSE)
  
  ensure_package("magrittr")
  
  # remove trailing slash in `parent_path`
  parent_path %<>% normalizePath()
  
  # ensure `parent_path` exists
  if ( !dir.exists(parent_path) ) dir.create(path = parent_path,
                                             recursive = TRUE)
  
  # generate sensible filename
  if ( is.null(filename) )
  {
    auto_name <- deparse(substitute(plotly_graph))
    
    filename <- dplyr::if_else(
      condition = auto_name == ".",
      true = "plotly_graph.html",
      false = paste0(deparse(substitute(plotly_graph)), ".html")
    )
  }
  
  filepath <- paste0(parent_path, "/", filename)
  
  htmlwidgets::saveWidget(
    widget = plotly_graph,
    file = filepath,
    selfcontained = selfcontained,
    libdir = libdir
  )
  
  if ( !is.null(disable_legend_toggling) )
  {
    test_char <- checkmate::check_choice(x = disable_legend_toggling,
                                         choices = "all")
    test_num <- checkmate::check_numeric(x = disable_legend_toggling,
                                         lower = 1,
                                         upper = length(plotly_graph$x$attrs),
                                         min.len = 1,
                                         max.len = length(plotly_graph$x$attrs),
                                         unique = TRUE,
                                         any.missing = FALSE,
                                         all.missing = FALSE)
    
    if ( !isTRUE(test_char) & !isTRUE(test_num) )
    {
      stop("Invalid argument provided: disable_legend_toggling\n",
           ifelse(!isTRUE(test_char) & is.character(disable_legend_toggling),
                  paste0(test_char, ". Or alternatively can also be a vector of integers >= 1 and <= number of traces."),
                  ""),
           ifelse(!isTRUE(test_num) & is.numeric(disable_legend_toggling),
                  paste0(test_num, ". Or alternatively can also be \"all\"."),
                  ""))
      
    } else if ( isTRUE(test_char) )
    {
      css_rules <-
        c("",
          "/* hides the svg dom element that has the click handler responsible for toggling */",
          ".legend .traces .legendtoggle {",
          "  display: none;",
          "}",
          "/* just for presentation: shows the default cursor instead of the text cursor */",
          ".legend .traces .legendtext {",
          "  cursor: default;",
          "}",
          "")
    } else
    {
      disable_legend_toggling %<>% as.integer()
      
      css_rules <-
        c("",
          "/* hides the svg dom element that has the click handler responsible for toggling */")
      
      for ( i in disable_legend_toggling )
      {
        css_rules %<>%
          c(paste0(".legend .groups:nth-of-type(", i, ") .legendtoggle",
                   dplyr::if_else(i == last(disable_legend_toggling),
                                  " {",
                                  ","), " "))
      }
      
      css_rules %<>%
        c("  display: none;",
          "}",
          "/* just for presentation: shows the default cursor instead of the text cursor */")
      
      for ( i in disable_legend_toggling )
      {
        css_rules %<>%
          c(paste0(".legend .groups:nth-of-type(", i, ") .legendtext",
                   dplyr::if_else(i == last(disable_legend_toggling),
                                  " {",
                                  ","), " "))
      }
      
      css_rules %<>%
        c("  cursor: default;",
          "}",
          "")
    }
    
    # write modified .css file
    plotly_dir <-
      list.dirs(path = paste0(parent_path, "/", libdir),
                full.names = TRUE,
                recursive = FALSE) %>%
      stringr::str_subset(pattern = "plotlyjs")
    
    readr::read_lines(file = paste0(plotly_dir, "/plotly-htmlwidgets.css")) %>%
      c(css_rules) %>%
      readr::write_lines(path = paste0(plotly_dir, "/plotly_htmlwidgets_custom.css"),
                         append = FALSE)
    
    # modify dependency path in HTML file
    readr::read_file(file = filepath) %>%
      stringr::str_replace(pattern = "plotly-htmlwidgets\\.css",
                           replacement = "plotly_htmlwidgets_custom.css") %>%
      readr::write_file(path = filepath,
                        append = FALSE)
  }
  
  if ( !is.null(add_web_font) )
  {
    webfont_tag <-
      "<link href=\"" %>%
      paste0(checkmate::assert_character(x = add_web_font,
                                         pattern = "^https?://\\w.*",
                                         ignore.case = TRUE,
                                         any.missing = FALSE,
                                         all.missing = FALSE,
                                         unique = TRUE)) %>%
      paste0("\" rel=\"stylesheet\" />")
    
    readr::read_file(file = filepath) %>%
      stringr::str_replace(pattern = "<link href=",
                           replacement = paste0(webfont_tag, "\n<link href=")) %>%
      readr::write_file(path = filepath,
                        append = FALSE)
  }
}

autocrop_png <- function(path_to_png)
{
  ensure_package("magrittr")
  ensure_package(package = "imager",
                 load = FALSE)
  
  imager::load.image(file = path_to_png) %>%
    imager::autocrop() %>%
    imager::pad(nPix = 4,
                axes = "xy",
                pos = 0) %>%
    imager::flatten.alpha() %>%
    imager::save.image(file = path_to_png)
}

Can't get it to work sadly.
First I got errors %<>% function doesn't exist, but that stopped somehow,.

p <- plot_ly(data = mtcars, x = ~cyl, y = ~mpg, type = 'scatter', mode = 'markers')
 export_plotly2SVG(p, filename = "happyplot.svg")

gives me this:

Error in setwd(dir) : cannot change working directory

changing it to this:
export_plotly2SVG(p, filename = "happyplot.svg", parent_path = getwd())

gives me this:

Error: 'C:/Users/Cyto/Documents\plotly_temp_1adc6206a4a.html' does not exist.
and this
export_plotly2SVG(p, filename = "happyplot.svg", parent_path = "C:/Users/Cyto/Documents/")
gave me this:

Error in checkError(res) :
Undefined error in httr call. httr output: Failed to connect to localhost port 4567: Connection refused
In addition: Warning message:
In RSelenium::rsDriver(browser = "chrome", extraCapabilities = list(chromeOptions = list(prefs = list(profile.default_content_settings.popups = 0L, :

Show Traceback

Rerun with Debug
Error in checkError(res) :
Undefined error in httr call. httr output: Failed to connect to localhost port 4567: Connection refused

Hi Mark,

Yeah sorry, I didn't really test that code outside of my particular use case 😬. There are probably more issues you could run into. Anyway, to address those you mentioned I adapted the above gist. Just try out the latest revision, you're example should work fine now.

BTW, it seems you didn't have the package magrittr installed (i.a. it features the compound assignment pipe-operator %<>%). IMHO it's really worth to get accustomed to that piping syntax, it's just so much more readable and intuitive 😉.

This works great. Thanks very much.

The only issue I had was after the fact. My version of Adobe doesn't have Work Sans and so the svg just wouldn't open in Illustrator and only gave an unhelpful error message. Not sure how often this will be an issue for people but maybe switching the default to Arial or something like that would be useful.

@salmin-b: Thank you very much for this nice function! Works nice (ubuntu16.04, R3.4.4).
I searched before long but didn't found this solution to the problem (how to get plotly graphs as svg).

When first trying, my RStudio complained about some corrupt .rdb file in "XML".
Restarting R solved the error (following lme4/lme4#407).
For the case that somebody also encounters this problem...

for the sake of compatibility with Adobe Illustrator (as @knightjdr mentioned),
it might be better to replace
font_family = "Work Sans" by font_family = "Arial", for those like me, who have collaborators/coworkers
who want to edit the figure with Adobe Illustrator for creating scientific figures.

for the sake of compatibility with Adobe Illustrator (as @knightjdr mentioned), it might be better to replace font_family = "Work Sans" by font_family = "Arial"

done :)

Hi there, thanks so much for this function! I managed to get the svg plot but the main plot elements (points, axes, text etc) are not editable for me in Illustrator. The scale bar and legend are editable though. Any ideas??
Best,
Steve

Hi there, thanks so much for this function! I managed to get the svg plot but the main plot elements (points, axes, text etc) are not editable for me in Illustrator. The scale bar and legend are editable though. Any ideas?? Best, Steve

Same here. Any ideas +1??