MathJax support

NAMESPACE

@@ -81,6 +81,7 @@ S3method(to_basic,default)
 S3method(transmute_,plotly)
 S3method(ungroup,plotly)
 export("%>%")
+export(TeX)
 export(add_annotations)
 export(add_area)
 export(add_bars)

NEWS.md

@@ -22,7 +22,7 @@
 * The `plot_geo()` function gains a `offline` argument for rendering `"scattergeo"` traces with or without an internet connection (#356). Leveraging this argument requires the new **plotlyGeoAssets** package.
 * Instead of an error, `ggplotly(NULL, "message")` and `plotly_build(NULL, "message")` now returns `htmltools::div("message")`, making it easier to relay messages in shiny when data isn't yet ready to plot (#1116).
 * The `animation_button()` function gains a `label` argument, making it easier to control the label of an animation button generated through the `frame` API (#1205).
-* Support for async rendering of inside **shiny** apps using the [promises](https://rstudio.github.io/promises/) package (#1209).
+* Support for async rendering of inside **shiny** apps using the [promises](https://rstudio.github.io/promises/) package (#1209). For an example, run `plotly_example("shiny", "async")`.
 
 ## CHANGES
 
@@ -36,6 +36,7 @@
 
 ### Other changes relevant for all **plotly** objects
 
+* All axis objects now default to `automargin = TRUE`. The majority of the time this should make axis labels more readable, but may have un-intended consequences in some rare cases (#1252). 
 * The `elementId` field is no longer populated, which fixes the "Ignoring explicitly provided widget ID" warning in shiny applications (#985).
 
 ## BUG FIXES

R/layout.R

@@ -91,6 +91,13 @@ rangeslider <- function(p, start = NULL, end = NULL, ...) {
 #' @param collaborate include the collaborate mode bar button (unique to the R pkg)?
 #' @param cloud include the send data to cloud button?
 #' @param locale locale to use. See [here](https://github.com/plotly/plotly.js/tree/master/dist#to-include-localization) for more info.
+#' @param mathjax add [MathJax rendering support](https://github.com/plotly/plotly.js/tree/master/dist#to-support-mathjax).
+#' If `"cdn"`, mathjax is loaded externally (meaning an internet connection is needed for 
+#' TeX rendering). If `"local"`, the PLOTLY_MATHJAX_PATH environment variable must be
+#' set to the location (a local file path) of MathJax. IMPORTANT: plotly uses SVG-based 
+#' mathjax rendering which doesn't play nicely with HTML-based rendering (e.g., rmarkdown documents). 
+#' In this case, consider `<iframe>`-ing your plotly graph(s) into the larger document 
+#' (see [here](https://github.com/ropensci/plotly/blob/master/inst/examples/rmd/MathJax/index.Rmd) for an example).
 #' @author Carson Sievert
 #' @export
 #' @examples
@@ -103,21 +110,23 @@ rangeslider <- function(p, start = NULL, end = NULL, ...) {
 #' # remove the plotly logo and collaborate button from modebar
 #' config(p, displaylogo = FALSE, collaborate = FALSE)
 #' 
+#' # enable mathjax
+#' # see more examples at https://plot.ly/r/LaTeX/
+#' plot_ly(x = c(1, 2, 3, 4), y = c(1, 4, 9, 16)) %>%
+#'   layout(title = TeX("\\text{Some mathjax: }\\alpha+\\beta x")) %>%
+#'   config(mathjax = "cdn")
+#' 
 #' # japanese
 #' config(p, locale = "ja")
 #' # german
 #' config(p, locale = "de")
-#' # swiss-german
-#' config(p, locale = "de-CH")
 #' # spanish
 #' config(p, locale = "es")
-#' # french
-#' config(p, locale = "fr")
 #' # chinese
 #' config(p, locale = "zh-CN")
 #' 
 
-config <- function(p, ..., collaborate = TRUE, cloud = FALSE, locale = NULL) {
+config <- function(p, ..., collaborate = TRUE, cloud = FALSE, locale = NULL, mathjax = NULL) {
 
   if (!is.null(locale)) {
     p$dependencies <- c(
@@ -127,6 +136,21 @@ config <- function(p, ..., collaborate = TRUE, cloud = FALSE, locale = NULL) {
     p$x$config$locale <- locale
   }
 
+  if (!is.null(mathjax)) {
+    mj <- switch(
+      match.arg(mathjax, c("cdn", "local")),
+      cdn = mathjax_cdn(),
+      local = mathjax_local()
+    )
+    # if mathjax is already supplied overwrite it; otherwise, prepend it
+    depNames <- sapply(p$dependencies, "[[", "name")
+    if (any(idx <- depNames %in% "mathjax")) {
+      p$dependencies[[which(idx)]] <- mathjax
+    } else {
+      p$dependencies <- c(list(mj), p$dependencies)
+    }
+  }
+
   p$x$config <- modify_list(p$x$config, list(...))
 
   nms <- sapply(p$x$config[["modeBarButtonsToAdd"]], "[[", "name")

R/mathjax.R

@@ -0,0 +1,78 @@
+#' Render TeX in a plotly graph using MathJax
+#' 
+#' This function makes it slightly easier to render TeX in a plotly graph --
+#' it ensures that MathJax is included with the final result and also
+#' ensures the provided string is surrounded with `$` (this is what plotly.js
+#' uses to declare a string as TeX).
+#' 
+#' @param x a character vector
+#' @export
+#' @seealso [config]
+#' @examples 
+#' 
+#' plot_ly(x = c(1, 2, 3, 4), y = c(1, 4, 9, 16)) %>%
+#'   layout(title = TeX("\\text{Some mathjax: }\\alpha+\\beta x")) %>%
+#'   config(mathjax = "cdn")
+
+TeX <- function(x) {
+  startsWithDollar <- grepl("^\\$", x)
+  endsWithDollar <- grepl("\\$$", x)
+  x <- paste0(if (!startsWithDollar) "$", x, if (!endsWithDollar) "$")
+  prefix_class(x, "TeX")
+}
+
+is.TeX <- function(x) {
+  inherits(x, "TeX")
+}
+
+mathjax_cdn <- function() {
+  htmltools::htmlDependency(
+    name = "mathjax",
+    version = "2.7.4",
+    src = c(file = depPath("mathjax")),
+    script = "cdn.js"
+  )
+}
+
+# TODO: wait until there is a more official way to include query parameters?
+# https://github.com/rstudio/htmltools/issues/98
+mathjax_local <- function() {
+  path <- mathjax_path()
+
+  mj <- file.path(path, "MathJax.js")
+  if (!file.exists(mj)) stop("Couldn't locate MathJax.js")
+
+  # parse the version
+  mathjax <- readLines(mj)
+  pat <- 'MathJax.fileversion="[0-9].[0-9].[0-9]'
+  ver <- regmatches(mathjax, regexpr(pat, mathjax))
+  ver <- sub('"', '', strsplit(ver, "=")[[1]][2])
+
+  # make sure we have access to the right config
+  config <- file.path(path, "config", "TeX-AMS-MML_SVG.js")
+  if (!file.exists(config)) stop("Couldn't locate necessary MathJax config: TeX-AMS-MML_SVG")
+
+  htmltools::htmlDependency(
+    name = "mathjax", 
+    version = ver, 
+    src = path,
+    script = c("MathJax.js", "config/TeX-AMS-MML_SVG.js")
+  )
+}
+
+
+mathjax_path <- function() {
+  path <- Sys.getenv("PLOTLY_MATHJAX_PATH", NA)
+
+  if (!is.na(path)) {
+    mj <- file.path(path, "MathJax.js")
+    if (!file.exists(mj)) stop("Couldn't find 'MathJax.js' file in local directory")
+    return(path)
+  }
+
+  stop(
+    "To use a local version of MathJax with plotly, set the PLOTLY_MATHJAX_PATH",
+    "environment variable to the location of MathJax.",
+    call. = FALSE
+  )
+}

R/orca.R

@@ -11,9 +11,10 @@
 #' Applies to all output images.
 #' @param height Sets the image height. If not set, defaults to `layout.height` value. 
 #' Applies to all output images.
-#' @param mathjax whether or not to specify a path to mathjax (required to export LaTeX characters).
-#' This should 'just work' in RStudio, but outside RStudio, you may have to set 
-#' the PLOTLY_MATHJAX_PATH environment variable to the location of MathJax.
+#' @param mathjax whether or not to include MathJax (required to render [TeX]).
+#' If `TRUE`, the PLOTLY_MATHJAX_PATH environment variable must be set and point 
+#' to the location of MathJax (this variable is also used to render [TeX] in 
+#' interactive graphs, see [config]).
 #' @param parallel_limit Sets the limit of parallel tasks run.
 #' @param verbose Turn on verbose logging on stdout.
 #' @param debug Starts app in debug mode and turn on verbose logs on stdout.
@@ -25,9 +26,7 @@
 #' 
 #' \dontrun{
 #' p <- plot_ly(z = ~volcano) %>% add_surface()
-#' orca(p, "surface-plot.png")
 #' orca(p, "surface-plot.svg")
-#' orca(p, "surface-plot.pdf")
 #' }
 #' 
 
@@ -65,25 +64,9 @@ orca <- function(p, file = "plot.png", format = tools::file_ext(file),
   if (!is.null(height)) args <- c(args, "--height", height)
   if (!is.null(parallel_limit)) args <- c(args, "--parallel-limit", parallel_limit)
   if (!is.na(mapbox_token())) args <- c(args, "--mapbox-access-token", mapbox_token())
-  if (isTRUE(mathjax)) args <- c(args, "--mathjax", mathjax_path())
+  if (isTRUE(mathjax)) args <- c(args, "--mathjax", file.path(mathjax_path(), "MathJax.js"))
 
   # TODO: point to local topojson? Should this only work if plot_geo(standalone = TRUE)?
   try_library("processx", "orca")
   invisible(processx::run("orca", args, echo = TRUE, spinner = TRUE))
 }
-
-
-mathjax_path <- function() {
-  if (is_rstudio()) {
-    try_library("rmarkdown", "orca")
-    return(getFromNamespace("pandoc_mathjax_local_path", "rmarkdown")())
-  }
-  path <- Sys.getenv("PLOTLY_MATHJAX_PATH", Sys.getenv("RMARKDOWN_MATHJAX_PATH", NA))
-  if (!is.na(path)) return(normalizePath(path, mustWork = TRUE))
-  stop(
-    "Please set either the RMARKDOWN_MATHJAX_PATH or PLOTLY_MATHJAX_PATH ",
-    "environment variable to the location of MathJax. ",
-    "On Linux systems you can also install MathJax using your system package manager.",
-    call. = FALSE
-  )
-}

R/plotly_build.R

@@ -371,6 +371,27 @@ plotly_build.plotly <- function(p, registerFrames = TRUE) {
   # box up 'data_array' attributes where appropriate
   p <- verify_attr_spec(p)
 
+
+  verify_mathjax <- function(p) {
+    hasMathjax <- "mathjax" %in% sapply(p$dependencies, "[[", "name")
+    if (hasMathjax) return(p)
+
+    hasTeX <- any(rapply(p$x, is.TeX))
+    if (!hasTeX) return(p)
+
+    # TODO: it would be much better to add the dependency here, but
+    # htmlwidgets doesn't currently support adding dependencies at print-time!
+    warning(
+      "Detected the use of `TeX()`, but mathjax has not been specified. ",
+      "Try running `config(.Last.value, mathjax = 'cdn')`",
+      call. = FALSE
+    )
+    p
+  }
+
+  # make sure we're including mathjax (if TeX() is used)
+  p <- verify_mathjax(p)
+
   # if a partial bundle was specified, make sure it supports the visualization
   p <- verify_partial_bundle(p)
 

inst/examples/rmd/MathJax/index.Rmd

@@ -0,0 +1,33 @@
+---
+title: "Render plotly MathJax inside rmarkdown"
+output: html_document
+---
+
+Some HTML-based MathJax:
+
+$$ \alpha+\beta $$
+
+You _could_ print this **plotly** graph with SVG-based rendering, but it would break the HTML-based rendering of **rmarkdown**!
+
+```{r message = FALSE}
+library(plotly)
+
+p <- plotly_empty() %>%
+  add_trace(x = 1, y = 1, text = TeX("\\alpha"), mode = "text", size = I(1000)) %>%
+  config(mathjax = "cdn")
+```
+
+Instead, use something like the **widgetframe** package to create a responsive iframe which ensure the SVG-based rendering that plotly requires is done independently of **rmarkdown**'s HTML-based rendering.
+
+```{r}
+widgetframe::frameableWidget(p)
+```
+
+Or, do it the old-fashioned way: save your plotly graph to an HTML file via `htmlwidgets::saveWidget()` then use an HTML `<iframe>`
+
+```{r}
+htmlwidgets::saveWidget(p, "my-plotly-plot.html")
+```
+
+
+<iframe src="my-plotly-plot.html" width="100%" height="400" id="igraph" scrolling="no" seamless="seamless" frameBorder="0"> </iframe>

inst/htmlwidgets/lib/mathjax/cdn.js

@@ -0,0 +1,4 @@
+var script = document.createElement("script");
+script.type = "text/javascript";
+script.src  = "https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.4/MathJax.js?config=TeX-AMS-MML_SVG";
+document.getElementsByTagName("head")[0].appendChild(script);