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)
}

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??