R-Plotly: Box Select - Extract x & y Coordinates

Question

For my project I need to extract the x and y coordinates of the “Box Select” which I use to select data within a shiny app (as I need to filter according to these values within a time frame). To be more precise - I need the actual coordinates only of the created box, not the x/y values of the selected IDs inside.

JS - Event Handlers <- I saw here that the event handler has these coordinates (x and y array) and you can see them in the console - but how do I store them dynamically within R?

Thanks already.

library(shiny)
library(plotly)

ui <- fluidPage(
   plotlyOutput('myPlot'),
   )

server <- function(input, output, session){
  output$myPlot = renderPlotly({
    plot_ly(data = iris, x = ~Sepal.Length, y = ~Petal.Length, color = ~Species) %>%
      layout(dragmode = "select")
  })
}

shinyApp(ui, server)

Answer 1

After trying around a lot I figured out that the data about the box range is not stored within the event_data of "selected", but they are available in both of "brushed" and "brushing".

Here is my solution to get the range of the created box:

library(shiny)
library(plotly)

ui <- fluidPage(
  plotlyOutput('myPlot'),
)

server <- function(input, output, session){

  output$myPlot = renderPlotly({
    plot_ly(data = iris, x = ~Sepal.Length, y = ~Petal.Length, color = ~Species, 
            type = 'scatter') %>%
      layout(dragmode = "select") %>%
      event_register(event = "plotly_brushed")
  })

  # Drag based selection in plotly graph
  selected_range <- reactiveVal({})
  observeEvent(event_data("plotly_brushed"), {
    # storing the values in a reactive value for later use
    selected_range(event_data("plotly_brushed"))

    # alternative method if you want to use it within the same observer/reactive  expression
    #xmin <- event_data("plotly_brushed")$x[1]
    #xmax <- event_data("plotly_brushed")$x[2]
    #ymin <- event_data("plotly_brushed")$y[1]
    #ymax <- event_data("plotly_brushed")$y[2]
  })
}

shinyApp(ui, server)