Widget list

NAMESPACE

@@ -3,8 +3,10 @@
 S3method(as.tags,htmlwidget)
 S3method(print,htmlwidget)
 S3method(print,suppress_viewer)
+S3method(print,widgetList)
 export(JS)
 export(appendContent)
+export(as.widgetList)
 export(createWidget)
 export(onRender)
 export(onStaticRenderComplete)
@@ -14,4 +16,5 @@ export(scaffoldWidget)
 export(shinyRenderWidget)
 export(shinyWidgetOutput)
 export(sizingPolicy)
+export(widgetList)
 import(htmltools)

NEWS

@@ -8,6 +8,9 @@ htmlwidgets 0.5.2 (unreleased)
   e.g. larger embedded leaflet maps). Stack size can also be controlled
   by the pandoc.stack.size option.
 
+* Added new functions `widgetList()` and `as.widgetList()` to combine multiple
+  HTML widgets into a list, and render all of them when the list is printed in
+  the R console or R Markdown or Shiny apps. (#110)
 
 htmlwidgets 0.5
 -----------------------------------------------------------------------

R/htmlwidgets.R

@@ -1,32 +1,29 @@
 #' @export
 print.htmlwidget <- function(x, ..., view = interactive()) {
+  # call html_print with the viewer
+  html_print(htmltools::as.tags(x, standalone=TRUE), viewer = if (view) viewerFunc(x))
+
+  # return value
+  invisible(x)
+}
 
+viewerFunc <- function(x) {
   # if we have a viewer then forward viewer pane height (if any)
   viewer <- getOption("viewer")
-  if (!is.null(viewer)) {
-    viewerFunc <- function(url) {
 
-      # get the requested pane height (it defaults to NULL)
-      paneHeight <- x$sizingPolicy$viewer$paneHeight
+  if (is.null(viewer)) utils::browseURL else function(url) {
+    # get the requested pane height (it defaults to NULL)
+    paneHeight <- x$sizingPolicy$viewer$paneHeight
 
-      # convert maximize to -1 for compatibility with older versions of rstudio
-      # (newer versions convert 'maximize' to -1 interally, older versions
-      # will simply ignore the height if it's less than zero)
-      if (identical(paneHeight, "maximize"))
-        paneHeight <- -1
+    # convert maximize to -1 for compatibility with older versions of rstudio
+    # (newer versions convert 'maximize' to -1 interally, older versions will
+    # simply ignore the height if it's less than zero)
+    if (identical(paneHeight, "maximize"))
+      paneHeight <- -1
 
-      # call the viewer
-      viewer(url, height = paneHeight)
-    }
-  } else {
-    viewerFunc <- utils::browseURL
+    # call the viewer
+    viewer(url, height = paneHeight)
   }
-
-  # call html_print with the viewer
-  html_print(htmltools::as.tags(x, standalone=TRUE), viewer = if (view) viewerFunc)
-
-  # return value
-  invisible(x)
 }
 
 #' @export
@@ -119,6 +116,35 @@ addHook <- function(x, hookName, jsCode) {
 }
 
 
+#' Widget lists
+#'
+#' Combine multiple HTML widgets into a list, and all widgets will be rendered
+#' on the same page when the widget list is printed.
+#' @param ... HTML widget objects created by \code{createWidget()} or widget
+#'   packages, and (optionally) HTML elements created from \pkg{htmltools}
+#' @export
+widgetList <- function(...) {
+  as.widgetList(list(...))
+}
+
+#' @param x a list to be coerced to a widget list
+#' @rdname widgetList
+#' @export
+as.widgetList <- function(x) {
+  if (!is.list(x)) stop("'x' must be a list")
+  for (i in seq_along(x)) {
+    if (!inherits(x[[i]], c('htmlwidget', 'html', 'shiny.tag', 'shiny.tag.list')))
+      stop("The element ", i, " in 'x' is not an HTML widget or tag")
+  }
+  structure(x, class = 'widgetList')
+}
+
+#' @export
+print.widgetList <- function(x, ..., view = interactive()) {
+  html_print(lapply(x, as.tags), viewer = if (view) viewerFunc(list()))
+  invisible(x)
+}
+
 toHTML <- function(x, standalone = FALSE, knitrOptions = NULL) {
 
   sizeInfo <- resolveSizing(x, x$sizingPolicy, standalone = standalone, knitrOptions = knitrOptions)

R/knitr-methods.R

@@ -29,7 +29,8 @@ registerMethods <- function(methods) {
   # htmlwidgets and knitr are loaded.
   registerMethods(list(
     # c(package, genname, class)
-    c("knitr", "knit_print", "htmlwidget")
+    c("knitr", "knit_print", "htmlwidget"),
+    c("knitr", "knit_print", "widgetList")
   ))
 }
 
@@ -42,3 +43,6 @@ knit_print.htmlwidget <- function(x, ..., options = NULL) {
   knitr::knit_print(toHTML(x, standalone = FALSE, knitrOptions = options), options = options,  ...)
 }
 
+knit_print.widgetList <- function(x, ..., options = NULL) {
+  structure(lapply(x, knitr::knit_print, ..., options = options), class = 'knit_asis_list')
+}

man/widgetList.Rd

@@ -0,0 +1,22 @@
+% Generated by roxygen2 (4.1.1): do not edit by hand
+% Please edit documentation in R/htmlwidgets.R
+\name{widgetList}
+\alias{as.widgetList}
+\alias{widgetList}
+\title{Widget lists}
+\usage{
+widgetList(...)
+
+as.widgetList(x)
+}
+\arguments{
+\item{...}{HTML widget objects created by \code{createWidget()} or widget
+packages, and (optionally) HTML elements created from \pkg{htmltools}}
+
+\item{x}{a list to be coerced to a widget list}
+}
+\description{
+Combine multiple HTML widgets into a list, and all widgets will be rendered
+on the same page when the widget list is printed.
+}
+