Add alt text to all rglwidgets.

DESCRIPTION

@@ -1,5 +1,5 @@
 Package: rgl
-Version: 1.1.3
+Version: 1.1.4
 Title: 3D Visualization Using OpenGL
 Authors@R: c(person("Duncan", "Murdoch", role = c("aut", "cre"),
  email = "[email protected]"),

NEWS.md

@@ -1,3 +1,8 @@
+# rgl 1.1.4
+
+* Support for "alt" text has been added to `rglwidget()`, with
+partial support for the `fig.alt` setting in `knitr`.
+
 # rgl 1.1.3
 
 ## Major changes

R/knitr.R

@@ -244,7 +244,8 @@ fns <- local({
  content <- rglwidget(scene,
  width = x$width,
  height = x$height,
- webgl = !doSnapshot)
+ webgl = !doSnapshot,
+ altText = c(options$fig.alt, paste("rglwidget in chunk", options$label))[1])
  if (inherits(content, "knit_image_paths")) {
  # # We've done a snapshot, put it in the right place.
  name <- fig_path("-rgl.png", options, rgl_counter())

R/rglwidget.R

@@ -265,7 +265,8 @@ rglwidget <- local({
  minimal = TRUE, 
  webgl,
  snapshot,
- shinyBrush = NULL, ...,
+ shinyBrush = NULL, 
+ altText = "rglwidget", ...,
  oldConvertBBox = FALSE) {
 
  if (missing(snapshot)) {
@@ -352,6 +353,8 @@ rglwidget <- local({
  x$players <- upstream$players
 
  x$webGLoptions <- webGLoptions
+
+ x$altText <- altText
 
  # create widget
  attr(x, "TOJSON_ARGS") <- list(na = "string")

inst/htmlwidgets/lib/rglClass/init.src.js

@@ -1230,6 +1230,7 @@
  this.onContextRestored, false);
  newcanvas.addEventListener("webglcontextlost",
  this.onContextLost, false);
+ newcanvas.appendChild(document.createTextNode(this.scene.altText));
  while (this.el.firstChild) {
  this.el.removeChild(this.el.firstChild);
  }

man/rglwidget.Rd

@@ -18,6 +18,7 @@ rglwidget(x = scene3d(minimal), width = figWidth(), height = figHeight(),
  shared = NULL, minimal = TRUE, 
  webgl, snapshot, 
  shinyBrush = NULL, 
+ altText = "rglwidget",
  ...,
  oldConvertBBox = FALSE)
 }
@@ -46,6 +47,8 @@ component that will hold the scene.
  no effect? See \code{\link{scene3d}}.}
  \item{shinyBrush}{The name of a Shiny \code{input} element
  to receive information about mouse selections.}
+ \item{altText}{Text to include for screen-readers or browsers
+ that don't handle WebGL.}
  \item{oldConvertBBox}{See Details below.}
  \item{...}{Additional arguments
 to pass to \code{htmlwidgets::\link{createWidget}}.}

man/setupKnitr.Rd

@@ -17,7 +17,8 @@ where appropriate, according to the \code{fig.keep} chunk option.
 By default (\code{fig.keep = "high"}), only high-level plots
 are kept, after low-level changes have been merged into them.
 See the \pkg{knitr} documentation 
-\url{https://yihui.org/knitr/options/#plots} for more details. To suppress auto-printing, the RGL calls
+\url{https://yihui.org/knitr/options/#plots} for more details.
+To suppress auto-printing, the RGL calls
 can be wrapped in \code{\link{invisible}()}. 
 Similarly to \pkg{grid} graphics (used by \pkg{lattice}
 and \pkg{ggplot2}), automatic inclusion requires the object
@@ -106,6 +107,12 @@ display of plots.
  \item \code{rgl.keepopen}: no longer used. Ignored
  with a warning.
 
+ \item \code{fig.alt} is partially supported: \pkg{rgl}
+will always use the first entry if \code{fig.alt} is a vector.
+Other graphics types match the entries in \code{fig.alt}
+to successive plots within the chunk.
+(This is due to a limitation in \pkg{knitr}, and may
+change in the future.)
 }
 }
 \value{