tests/testthat/quartz_png/app.R

In rstudio/thematic: Unified and Automatic 'Theming' of 'ggplot2', 'lattice', and 'base' R Graphics

library(shiny)
library(ggplot2)
library(thematic)

thematic_shiny("black", "white", font = font_spec("Pacifico", 1.25, update = TRUE))

ui <- fluidPage(
  imageOutput("quartz")
)

server <- function(input, output, session) {
  output$quartz <- snapshotPreprocessOutput(renderImage({
    file <- thematic_save_plot(
      qplot(1:10) + ggtitle("quartz png"),
      device = grDevices::png
    )
    list(src = file, width = 480, height = 480)
  }), function(value) {})
}

shinyApp(ui, server)