Render MAIDR Plot in Shiny Server

Creates a Shiny render function for MAIDR widgets using htmlwidgets. This provides automatic dependency injection and robust JavaScript initialization.

Usage

render_maidr(
  expr,
  env = parent.frame(),
  quoted = FALSE,
  fig_width = NULL,
  fig_height = NULL
)

Arguments

expr

An expression that draws a plot. Either a ggplot object or a lattice (trellis) object, returned rather than printed, or Base R plotting calls – their return values differ (plot() returns NULL, barplot() returns bar midpoints) and are ignored; what counts is whether the expression drew. An expression that draws nothing and returns NULL renders nothing, per Shiny convention.

env

The environment in which to evaluate expr

quoted

Is expr a quoted expression

fig_width, fig_height

The size to draw the chart at, in inches, as width and height set it in show(): each a single positive number no larger than 50, or NULL (the default) for 7 x 5 in, 12 x 6 in for a candlestick chart. They are not the size of the output on the page, which maidr_output()'s width and height set: a chart wider than its output shrinks to fit it. Nothing sizes the chart to its output; the size is the one given here.

Value

A Shiny render function for use in server

Examples

if (interactive()) {
  library(shiny)
  library(ggplot2)
  server <- function(input, output) {
    output$myplot <- render_maidr({
      ggplot(mtcars, aes(x = factor(cyl), y = mpg)) +
        geom_bar(stat = "identity")
    })

    # Drawn 10 inches wide and 4 high
    output$wide <- render_maidr(
      {
        ggplot(mtcars, aes(x = wt, y = mpg)) +
          geom_point()
      },
      fig_width = 10,
      fig_height = 4
    )
  }
}