Show tooltip when hovering on flexdashboard plot in JS or hover action

user_12800405 0
Viewed 629

I have the following sample flexdashboard:

---
title: "Hover"
output: 
  flexdashboard::flex_dashboard:
    orientation: columns
    vertical_layout: fill
runtime: shiny
---

```{r setup, include=FALSE}
library(flexdashboard)
library(tidyverse)
data(iris)

Column {data-width=650}
-----------------------------------------------------------------------

### Chart A

```{r}
iris %>% group_by(Species) %>% 
  summarise(mean = mean(Sepal.Length)) %>% 
  ggplot(aes(Species, mean)) + geom_col()

What I want is a tooltip when hovering over the bars in the plot and show its values. I read this article in SO How do I show the y value on tooltip while hover in ggplot2 but it works for Shiny. I tried this:

p <- iris %>% group_by(Species) %>% 
  summarise(mean = mean(Sepal.Length))

labels <- sprintf("<strong>%s</strong><br/>Mean: %f", 
                     p$Species, p$mean) %>% 
     lapply(htmltools::HTML)

p %>% ggplot(aes(Species, mean)) + geom_col() + geom_text(aes(label = labels))

This creates an html tool with the specie and value, what I don't have is the hover (plot_hover maybe?) to show the tooltip.

Any help will be greatly appreciated

Regards,

flexdashboard r
2 Answers

Here is a way. You have to target the top center of a bar to get the tooltip.

---
title: "Untitled"
runtime: shiny
output: 
  flexdashboard::flex_dashboard:
    orientation: columns
    vertical_layout: fill
---

```{r setup, include=FALSE}
library(flexdashboard)
library(dplyr)
library(ggplot2)
library(shiny)
```

Column {data-width=650}
-----------------------------------------------------------------------

### Chart A

```{r}
dat <- iris %>% group_by(Species) %>% 
  summarise(mean = mean(Sepal.Length))
output[["ggplot"]] <- renderPlot({
  dat %>% 
  ggplot(aes(Species, mean)) + geom_col()
})
output[["hoverinfo"]] <- renderUI({ 
  hover <- input[["plot_hover"]]
  if(is.null(hover)) return(NULL)
  point <- nearPoints(dat, hover, threshold = 50, maxpoints = 1)
  if(nrow(point) == 0) return(NULL)
  left_px <- hover$coords_css$x
  top_px <- hover$coords_css$y
  style <- 
    paste0("position:absolute; z-index:100; background-color: rgba(245, 245, 245, 0.85); ",
           "left:", left_px, 
           "px; top:", top_px, "px;")
  # tooltip created as wellPanel
  tooltip <- paste0(
    "<b> Species: </b>", point[["Species"]], "<br/>",
    "<b> mean: </b>", point[["mean"]]
  )
  wellPanel(
    style = style, p(HTML(tooltip))
  )
}) 
plotOutput("ggplot", hover = hoverOpts("plot_hover"))
div(uiOutput("hoverinfo"), style = "pointer-events: none;")
```
user_11001070

I tried many different options with shinyBs, and the others described here, but I still had issues with adding tooltips without using runtime: shiny, so I added

output:
    includes:
       in_header: my_custom.html

And in my_custom.html I had:

<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
<script>
$( function() {
  $( document ).tooltip(
    {
      position: {
        using: function( position, feedback ) {
          $( this ).css( position );
          $( "<div>" )
            .addClass( "arrow" )
            .addClass( feedback.vertical )
            .addClass( feedback.horizontal )
            .appendTo( this );
        }
      },
      show: {
        effect: "slideDown",
        delay: 500
      }
    }
  );
} );
</script>

Other options for styling could be found here

user_74247160
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