Plot Output — renderPlot

v1.8.1|Source: R/render-plot.R

Description

Renders a reactive plot that is suitable for assigning to an output slot.

renderPlot(
  expr,
  width = "auto",
  height = "auto",
  res = 72,
  ...,
  alt = NA,
  env = parent.frame(),
  quoted = FALSE,
  execOnResize = FALSE,
  outputArgs = list()
)

Arguments

expr

An expression that generates a plot.

width, height

Height and width can be specified in three ways:

  • "auto", the default, uses the size specified by plotOutput() (i.e. the offsetWidth/`offsetHeight`` of the HTML element bound to this plot.)

  • An integer, defining the width/height in pixels.

  • A function that returns the width/height in pixels (or "auto"). The function is executed in a reactive context so that you can refer to reactive values and expression to make the width/height reactive.

When rendering an inline plot, you must provide numeric values (in pixels) to both width and height.

res

Resolution of resulting plot, in pixels per inch. This value is passed to plotPNG(). Note that this affects the resolution of PNG rendering in R; it won't change the actual ppi of the browser.

...

Arguments to be passed through to plotPNG(). These can be used to set the width, height, background color, etc.

alt

Alternate text for the HTML <img> tag if it cannot be displayed or viewed (i.e., the user uses a screen reader). In addition to a character string, the value may be a reactive expression (or a function referencing reactive values) that returns a character string. If the value is NA (the default), then ggplot2::get_alt_text() is used to extract alt text from ggplot objects; for other plots, NA results in alt text of "Plot object". NULL or "" is not recommended because those should be limited to decorative images.

env

The parent environment for the reactive expression. By default, this is the calling environment, the same as when defining an ordinary non-reactive expression. If expr is a quosure and quoted is TRUE, then env is ignored.

quoted

If it is TRUE, then the quote()ed value of expr will be used when expr is evaluated. If expr is a quosure and you would like to use its expression as a value for expr, then you must set quoted to TRUE.

execOnResize

If FALSE (the default), then when a plot is resized, Shiny will replay the plot drawing commands with grDevices::replayPlot() instead of re-executing expr. This can result in faster plot redrawing, but there may be rare cases where it is undesirable. If you encounter problems when resizing a plot, you can have Shiny re-execute the code on resize by setting this to TRUE.

outputArgs

A list of arguments to be passed through to the implicit call to plotOutput() when renderPlot is used in an interactive R Markdown document.

Details

The corresponding HTML output tag should be div or img and have the CSS class name shiny-plot-output.

Interactive plots

With ggplot2 graphics, the code in renderPlot should return a ggplot object; if instead the code prints the ggplot2 object with something like print(p), then the coordinates for interactive graphics will not be properly scaled to the data space.

See plotOutput() for more information about interactive plots.

See also

For the corresponding client-side output function, and example usage, see plotOutput(). For more details on how the plots are generated, and how to control the output, see plotPNG(). renderCachedPlot() offers a way to cache generated plots to expedite the rendering of identical plots.