Add Permanent Shaded Rectangle With Select Box Corners In Plotly R

This is a continuation of a previous post (Add shaded rectangle with select Box corners in Plotly R). I am creating an application where if a user employs the Box Select tool in Pl

Solution 1:

This does what you want, I made the following additions:

• The rectangles are stored in a variable (rects) with more long lasting scope
• They are made available to the shiny program using the onInputChange event handler.
• As they come over as a big character vector, they need to be converted to a dataframe before being printed out

Here is the code:

library(ggplot2)
library(shiny)
library(plotly)
library(htmlwidgets)

ui <- basicPage(
  plotlyOutput("plot1"),
  verbatimTextOutput("rectdf")
)

server <- function(input, output) {

  p <- ggplot(mtcars, aes(x = wt, y = mpg)) + geom_point(alpha=0) + xlim(0,5) +ylim(-3,3)
  gp <- ggplotly(p)

  set.seed(3)
  myDF <- data.frame(X1=rnorm(10,-1), X2=rnorm(10,-1), X3=rnorm(10,-1), X4=rnorm(10,1), X5=rnorm(10,1), X6=rnorm(10,1))
  colNms <- colnames(myDF)
  nVar <- length(colNms)

  inputRectDf <- reactive({
    req(input$rects)# data comes back as a big character vector# so we reformat it as a dataframe here
    df <- data.frame(t(matrix(input$rects,nrow=8)))
    names(df) <- names(input$rects)[1:8]
    return(df)
  })
  output$rectdf <- renderPrint({print(inputRectDf())})


  output$plot1 <- renderPlotly({
    gp %>% layout(dragmode="select") %>%
      onRender("
               function(el, x, data) {
               var rects = [];

               var myDF = data.myDF
               var Traces = [];
               var dLength = myDF.length
               var vLength = data.nVar
               var cNames = data.colNms
               for (a=0; a<dLength; a++){
               xArr = [];
               yArr = [];
               for (b=0; b<vLength; b++){
               xArr.push(b)
               yArr.push(myDF[a][cNames[b]]);
               }
               var pcpLine = {
               x: xArr,
               y: yArr,
               mode: 'lines',
               line: {
               color: 'orange',
               width: 1
               },
               opacity: 0.9,
               }
               Traces.push(pcpLine);
               }
               Plotly.addTraces(el.id, Traces);

               el.on('plotly_selected', function(e) {
               var dLength = myDF.length
               var selectedPCP = []
               var xMin = e.range.x[0]
               var xMax = e.range.x[1]
               var yMin = e.range.y[0]
               var yMax = e.range.y[1]

               console.log([xMin, xMax, yMin, yMax])

               var Traces = []
               var drawRect = {
               type: 'rect',
               x0: xMin,
               y0: yMin,
               x1: xMax,
               y1: yMax,
               line: {
               color: 'green',
               width: 1
               },
               fillcolor: 'green'
               }
               rects.push(drawRect);
               var update = {
               shapes:rects
               }
               Plotly.relayout(el.id, update)
               Shiny.onInputChange('rects', rects); // make the rects available to shiny
               })
               }", data = list(myDF = myDF, nVar = nVar, colNms = colNms))})

  }
shinyApp(ui, server)

And here is the output, showing a few rectangles being selected and output: