launch_shiny: Launch Shiny application by clicking on its screenshot.

In SciViews/learndown: R Markdown, Bookdown and Learnr Additions for Learning Material

Launch Shiny application by clicking on its screenshot.

Description

Shiny applications can be embedded in certain R Markdown documents. However, the application is automatically loaded at the same time as the main page, and that may not be the desired behavior. With launch_shiny(), you display just a screenshot of the Shiny application in the page. The user has to click on it to actually launch the application (that replaces the screenshot on the page).

Usage

launch_shiny(
  url,
  app = sub("\\?.+$", "", basename(url)),
  imgdir = "images/shinyapps",
  img = paste0(imgdir, "/", app, ".png"),
  createimg = TRUE,
  width = 790,
  height = 500,
  fun = NULL,
  alt1 = "*Click to start the Shiny application.*",
  alt2 = paste0("*Click to start",
    "or [run `{run.cmd}`]({run.url}{run.arg}){{target=\"_blank\"}}.*"),
  toc = "",
  toc.def = "Shiny application {app}",
  run.url = "start_rstudio.html?runrcode=",
  run.cmd = glue("{fun}(\"{app}\")"),
  run.arg = URLencode(run.cmd, reserved = TRUE),
  app.img = "images/list-app.png",
  app.link = "shiny_app",
  ...
)

Arguments

url	The URL of the Shiny application. If both ⁠app =⁠ and ⁠baseurl =⁠ are provided, you don't need to specify it.
app	Name of the shiny application (cannot be duplicated on a page).
imgdir	The directory without trailing "/" where images relative to Shiny applications are stored. By default, it is relative to current directory, in images/shinyapps subdirectories.
img	The relative or absolute path to the image with a screenshot of the Shiny application, as produced by webshot_shiny().
createimg	If the app image (img) is not found, and there is no default image in ⁠imgdir =⁠, do we put it there (yes be default)?
width	The width of the image and iframe for the app.
height	The height of image and iframe.
fun	The function to run as alternative to start the Shiny application locally. It is better to fully specify it (⁠package::function⁠), and it should take one argument which is the application name in ⁠app =⁠.
alt1	Alternate text to display at the bottom of the screenshot when nothing is provided for ⁠fun =⁠. If NULL, nothing is displayed below the screenshot.
alt2	Alternate text to display at the bottom of the screenshot in case ⁠fun =⁠ is provided.
toc	Entry to use in the exercises table of content (NULL if no entry, "" for a default entry based on ⁠toc.def =⁠).
toc.def	Text for a default toc entry using glue() syntax for replacement, e.g., {app}.
run.url	The URL to use to start the Shiny application in RStudio server in the SciViews Box. It should generally end with ⁠?runrcode=⁠, and the R code to execute will be appended to it from ⁠run.arg =⁠.
run.cmd	The command to use to launch the Shiny application in RStudio.
run.arg	The URL encoded version of ⁠run.cmd =⁠.
app.img	The image to display in front of the toc entry
app.link	The link when the image is clicked (sends to an help page about Shiny applications).
...	Not used here, but it allows to add more arguments used by the screenshot addin, like ⁠delay =⁠, ⁠offsetx =⁠ or ⁠offsety =⁠, see webshot_shiny().

Value

The HTML content that creates the image and the iframe. The function must be called from within an R inline expression or from an R chunk with results='asis' in an HTML-rendered version of the R Markdown document to get the correct result.

See Also

webshot_shiny()

Examples

# TODO...

SciViews/learndown documentation built on Sept. 17, 2024, 8:06 a.m.