shiny Plot Caching

Published onesixx on 19-02-1519-02-15

https://shiny.rstudio.com/articles/plot-caching.html

output$plot <- renderCachedPlot(
    { 
      # Plotting code here...
    },
    cacheKeyExpr = { list(input$n, dataset()) }
)

improve the performance of your plots.
– using R’s base graphics instead of a plotting package
– using JavaScript graphics that render on the client instead of static plots that render on the server
– change the type of plot
( e.g. switching from ggplot2::geom_point to ggplot2::geom_hex )
– cache plots with renderCachedPlot()
코드변경을 최소로 하여

ui <- 	fluidPage(
	sidebarLayout(
		sidebarPanel(
			sliderInput("n", "Number of points", 4, 32, value = 8, step = 4),
			sliderInput("alpha", "Number of points", 0, 1, value = 0.5)
		),
		mainPanel(
			plotOutput("plot")
		)
	)
)
	
server <- function(input, output, session) {
	
	output$plot <- renderCachedPlot({
		Sys.sleep(2)  # Add an artificial delay
		rownums <- seq_len(input$n)
		aV <- isolate(input$alpha)
		cars [rownums,] %>% ggplot(aes(x=speed, y=dist)) + geom_point(alpha=aV) +
													xlim(range(cars$speed))+ ylim(range(cars$dist))
			
	},cacheKeyExpr = {c(input$alpha, input$n)})

}

shinyApp(ui, server)

cacheKeyExpr :
reactive expressions / reactive values / eventReactive() / observeEvent()

the value from cacheKeyExpr is actually serialized and then hashed,
and the resulting hash value is used as the key.

If you are hashing a large object, this may take a non-negligible amount of time

shiny Plot Caching

https://shiny.rstudio.com/articles/plot-caching.html

onesixx

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shiny Plot Caching

https://shiny.rstudio.com/articles/plot-caching.html

onesixx

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