In rstudio/shinycoreci: CI Testing for shiny

Since shiny 0.10.1, you can embed inline output elements. We have added an argument inline to a few output functions such as textOutput(), plotOutput(), and uiOutput(). This argument will be set to TRUE automatically when these types of output are rendered in the inline R expressions of R Markdown documents, e.g. `r '\x60r'` renderText(input$foo)`.

First we show a normal shiny app, with a select input to change the title of a plot, and a slider to change the size of points:

library(shiny)
sidebarLayout(
  sidebarPanel(
    selectizeInput('main', 'Main title', LETTERS),
    sliderInput('size', 'Point size', min = 0.2, max = 5, value = 1)
  ),
  mainPanel(
    renderPlot(plot(cars, main = input$main, cex = input$size, pch = 19),
               width = 600, height = 400)
  )
)

Now we use renderText() to render the plot title and point size in this paragraph. The main title is r renderText(input$main) and the point size is r renderText(input$size).

Besides renderText(), you can also embed some other output elements inline. We define a function to draw the sunspots data, with the aspect ratio value from a slider:

sunspots_line = function() {
  par(mar = rep(0, 4))
  plot(sunspots, axes = FALSE, ann = FALSE, asp = input$asp)
}
sunspots_width = function() {
  if (input$asp <= 0.11) 300 else 30/input$asp
}
sliderInput('asp', 'Change the aspect ratio', .02, .3, .2)

Here is a spark line r renderPlot(sunspots_line(), width=sunspots_width, height=40) that shows you the time series sunspots. Note when you render inline plots, you must provide both width and height values (in pixels), because it is not possible for shiny to figure out the width and height values automatically in this case. We used 40 as the fixed height here, and a changing width (calculated from the function sunspots_width()) depending on the aspect ratio.

rstudio/shinycoreci documentation built on April 11, 2025, 3:17 p.m.