Shiny: Request: plotOutput: a way to differentiate between click and brush

[daattali]

_Originally posted in shiny google group_

If I want to have a plot in my shiny app that the user can click on or choose certain regions, I'll use the click and brush arguments of plotOutput. However, when a brush is initiated, the click handler is also called. In some cases it can be useful to know when a click is made and when a brush is made, but if a click is part of a brush then I want to ignore it.

Example: in the following app, if you just brush (click some
k somewhere and drag the mouse), you get a "click" message as well as a "brush" message. I want to only get the "brush" message in that case.

library(shiny)
library(ggplot2)
runApp(shinyApp(
  ui = fluidPage(
    plotOutput("plot", click = "click", brush = "brush")
  ),
  server = function(input, output, session) {
    output$plot <- renderPlot({
      ggplot(mtcars, aes(wt, mpg)) + geom_point()
    })
    observeEvent(input$click, {
      cat("clicked\n")
    })
    observeEvent(input$brush, {
      cat("brushed\n")
    })
  }
))

I noticed that the click event is triggered on mousedown. If you agree with my proposed behaviour of not triggering a click when a brush is made, maybe a potential solution would be to change the trigger to be on mouseup, and when it happens check if a brush was made.

[wch]

This sounds like a good idea. There is some existing code that uses timing to distinguish between clicks and double-clicks, and something similar could be used for this as well.

[daattali]

Hi @wch , I just asked you in the Shiny devcon if this is still an issue. I just tried it, and a regular click does indeed still get registered the moment I mousedown on the plot. Shiny v0.13.0

[TomasHovorka]

Voting for this one. This is a nuisance. Thanks

[tvedebrink]

+1

[alandipert]

Still a thing; reproduced with Shiny 1.3.2.