Add info about printing ggplot objects

Author: wch

R/bootstrap.R

@@ -872,10 +872,16 @@ imageOutput <- function(outputId, width = "100%", height="400px",
 #'   \code{brush}.
 #'
 #'   For \code{plotOutput}, the coordinates will be sent scaled to the data
-#'   space, if possible. (At the moment, plots generated by base graphics
-#'   support this scaling, although plots generated by grid or ggplot2 do not.)
-#'   If scaling is not possible, the raw pixel coordinates will be sent. For
-#'   \code{imageOutput}, the coordinates will be sent in raw pixel coordinates.
+#'   space, if possible. (At the moment, plots generated by base graphics and
+#'   ggplot2 support this scaling, although plots generated by lattice and
+#'   others do not.) If scaling is not possible, the raw pixel coordinates will
+#'   be sent. For \code{imageOutput}, the coordinates will be sent in raw pixel
+#'   coordinates.
+#'
+#'   With ggplot2 graphics, the code in \code{renderPlot} should return a ggplot
+#'   object; if instead the code prints the ggplot2 object with something like
+#'   \code{print(p)}, then the coordinates for interactive graphics will not be
+#'   properly scaled to the data space.
 #'
 #' @param outputId output variable to read the plot/image from.
 #' @param width,height Image width/height. Must be a valid CSS unit (like
@@ -889,8 +895,8 @@ imageOutput <- function(outputId, width = "100%", height="400px",
 #'   created by the \code{\link{clickOpts}} function. If you use a value like
 #'   \code{"plot_click"} (or equivalently, \code{clickOpts(id="plot_click")}),
 #'   the plot will send coordinates to the server whenever it is clicked, and
-#'   the value will be accessible via \code{input$plot_click}. The value will
-#'   be a named list  with \code{x} and \code{y} elements indicating the mouse
+#'   the value will be accessible via \code{input$plot_click}. The value will be
+#'   a named list  with \code{x} and \code{y} elements indicating the mouse
 #'   position.
 #' @param dblclick This is just like the \code{click} argument, but for
 #'   double-click events.

man/plotOutput.Rd

@@ -30,8 +30,8 @@ because of how height is computed with HTML/CSS.}
 created by the \code{\link{clickOpts}} function. If you use a value like
 \code{"plot_click"} (or equivalently, \code{clickOpts(id="plot_click")}),
 the plot will send coordinates to the server whenever it is clicked, and
-the value will be accessible via \code{input$plot_click}. The value will
-be a named list  with \code{x} and \code{y} elements indicating the mouse
+the value will be accessible via \code{input$plot_click}. The value will be
+a named list  with \code{x} and \code{y} elements indicating the mouse
 position.}
 
 \item{dblclick}{This is just like the \code{click} argument, but for
@@ -97,10 +97,16 @@ The arguments \code{clickId} and \code{hoverId} only work for R base
   \code{brush}.
 
   For \code{plotOutput}, the coordinates will be sent scaled to the data
-  space, if possible. (At the moment, plots generated by base graphics
-  support this scaling, although plots generated by grid or ggplot2 do not.)
-  If scaling is not possible, the raw pixel coordinates will be sent. For
-  \code{imageOutput}, the coordinates will be sent in raw pixel coordinates.
+  space, if possible. (At the moment, plots generated by base graphics and
+  ggplot2 support this scaling, although plots generated by lattice and
+  others do not.) If scaling is not possible, the raw pixel coordinates will
+  be sent. For \code{imageOutput}, the coordinates will be sent in raw pixel
+  coordinates.
+
+  With ggplot2 graphics, the code in \code{renderPlot} should return a ggplot
+  object; if instead the code prints the ggplot2 object with something like
+  \code{print(p)}, then the coordinates for interactive graphics will not be
+  properly scaled to the data space.
 }
 \examples{
 # Only run these examples in interactive R sessions