ids theme: speaker notes overlay button for touch devices
The reveal.js speaker view ('s') opens a separate window, which is
awkward on mobile browsers. Add a button next to the fullscreen toggle
(shown on coarse-pointer devices only, like the fullscreen button) that
covers the slide with a full-screen overlay showing the current slide's
speaker notes, its title and planned time (from data-timing). The
overlay follows slide changes while open, closes with the X button or
Escape, is hidden in print output, and the button only appears when the
deck contains notes at all.
Change-Id: I50c6cd701115a973e8c6ba35448b13d5c722ab5a
diff --git a/R/revealjs_presentation.R b/R/revealjs_presentation.R
index 950b8b8..f641284 100644
--- a/R/revealjs_presentation.R
+++ b/R/revealjs_presentation.R
@@ -33,6 +33,12 @@
#' ```
#' to create notes only viewable in presentation mode.
#'
+#' On mobile browsers (touch devices), a button next to the fullscreen
+#' toggle overlays the current slide with its speaker notes (plus the slide
+#' title and, if present, the planned time from a timing comment), which is
+#' useful for practicing a talk on a phone or tablet. It follows along as
+#' you change slides and only appears if the deck contains notes at all.
+#'
#' ## Slide timing
#'
#' Speaker time can be planned per slide and per speaker by adding a comment