shinyscreenshot (version 0.2.1)

screenshotButton: Button that captures a screenshot of a shiny app

Description

Create a button that, when clicked, captures a screenshot of the Shiny app. Screenshots can be either of the entire viewable page (default), or of a specific section of the page. The captured image is automatically downloaded as a PNG image.

This function gets called from the UI portion of a Shiny app, unlike screenshot() which is similar but gets called from the server.

Usage

screenshotButton(
  selector = "body",
  filename = "shinyscreenshot",
  id = "",
  scale = 1,
  timer = 0,
  download = TRUE,
  server_dir = NULL,
  ns = shiny::NS(NULL),
  ...
)

Arguments

selector

CSS selector for the element that should be captured. If multiple elements match the selector, only the first one is captured. Default is to capture the entire page.

filename

Name of the file to be saved. A PNG extension will automatically be added.

id

As an alternative to selector, an ID of the element that should be captured can be provided. If id is provided, then selector is ignored. When used in a module, the id does need to be namespaced, like any other UI element.

scale

The scale of the image. Default is 1, which means the dimensions of the image will be exactly the dimensions in the browser. For example, a value of 2 will result in an image that's twice the height and width (and a larger file size).

timer

Number of seconds to wait before taking the screenshot. Default is 0, which takes a screenshot immediately.

download

If TRUE (default), download the screenshot image to the user's computer. If FALSE, the image isn't downloaded to the user, and a server_dir should be specified.

server_dir

Directory on the server where the screenshot image should be saved. See 'Saving to the server' section below.

ns

The namespace object of the current module if inside a Shiny module.

...

Any other parameters that should be passed along to the shiny::actionButton().

Saving to the server

By default, the image is downloaded to the user's computer and is not stored on the server running the Shiny app. If a server_dir is provided, then the image is stored to this directory on the server. Note that only the directory should be specified, not the file name.

If saving the image is successful, input$shinyscreenshot will contain the full path to the image. If not, input$shinyscreenshot will contain an empty string ("").

The directory must exist and be writeable. If NULL, the image is not saved to the server. If a relative path is provided, it is relative to the Shiny app's working directory. For example, server_dir="." will save the image in the same directory that the Shiny app is in.

See Also

screenshot()

Examples

if (interactive()) {
  library(shiny)
  library(shinyscreenshot)

  shinyApp(
    ui = fluidPage(
      h1("{shinyscreenshot} demo"),
      screenshotButton(label = "Capture entire page"),
      screenshotButton(label = "Capture plot", id = "plot"), br(), br(),
      numericInput("num", "Number of points", 50),
      plotOutput("plot")
    ),
    server = function(input, output) {
      output$plot <- renderPlot({
        plot(runif(input$num))
      })
    }
  )
}