A quick introduction

The ggiraph package let R users to make ggplot interactive. The package is an htmlwidget. Below an example:

It extends ggplot2 with new geom functions:

geom_bar_interactive
geom_boxplot_interactive
geom_line_interactive
geom_map_interactive
geom_path_interactive
geom_point_interactive
geom_polygon_interactive
geom_rect_interactive
geom_segment_interactive
geom_text_interactive
geom_tile_interactive

These understand three aesthetics to let you add interactivity:

tooltip: column of dataset that contains tooltips to be displayed when mouse is over elements.
onclick: column of dataset that contains javascript function to be executed when elements are clicked.
data_id: column of dataset that contains id to be associated with elements. This aesthetic is mandatory when you want to use an hover effect or when you want to enable selection of points in shiny applications.

Let’s prepare a ggplot object with mpg dataset.

library(ggiraph)

head(mpg)

## # A tibble: 6 × 11
##   manufacturer model displ  year   cyl      trans   drv   cty   hwy    fl
##          <chr> <chr> <dbl> <int> <int>      <chr> <chr> <int> <int> <chr>
## 1         audi    a4   1.8  1999     4   auto(l5)     f    18    29     p
## 2         audi    a4   1.8  1999     4 manual(m5)     f    21    29     p
## 3         audi    a4   2.0  2008     4 manual(m6)     f    20    31     p
## 4         audi    a4   2.0  2008     4   auto(av)     f    21    30     p
## 5         audi    a4   2.8  1999     6   auto(l5)     f    16    26     p
## 6         audi    a4   2.8  1999     6 manual(m5)     f    18    26     p
## # ... with 1 more variables: class <chr>

g <- ggplot(mpg, aes( x = displ, y = cty, color = hwy) ) + theme_minimal()

tooltips

The first example show how to add tooltip:

my_gg <- g + geom_point_interactive(aes(tooltip = model), size = 2) 
ggiraph(code = print(my_gg), width = .7)

hover effects

Now let’s add an hover effect. Elements associated with a data_id will be animated when mouse will be hover.

my_gg <- g + geom_point_interactive(
    aes(tooltip = model, data_id = model), size = 2) 
ggiraph(code = print(my_gg), width = .7, hover_css = "cursor:pointer;fill:red;stroke:red;")

Default value of hover css is hover_css = "fill:orange;". To see how to change that, read the custome_effects vignette.

Note that data-id can also be reused within a shiny application.

Click actions

Click actions must be a string column in the dataset containing valid javascript instructions.

crimes <- data.frame(state = tolower(rownames(USArrests)), USArrests)
head(crimes)

##                 state Murder Assault UrbanPop Rape
## Alabama       alabama   13.2     236       58 21.2
## Alaska         alaska   10.0     263       48 44.5
## Arizona       arizona    8.1     294       80 31.0
## Arkansas     arkansas    8.8     190       50 19.5
## California california    9.0     276       91 40.6
## Colorado     colorado    7.9     204       78 38.7

# create an 'onclick' column
crimes$onclick <- sprintf("window.open(\"%s%s\")",
  "http://en.wikipedia.org/wiki/", as.character(crimes$state) )

gg_crime <- ggplot(crimes, aes(x = Murder, y = Assault, color = UrbanPop )) + 
  geom_point_interactive(
    aes( data_id = state, tooltip = state, onclick = onclick ), size = 3 ) + 
  scale_colour_gradient(low = "#999999", high = "#FF3333") + 
  theme_minimal()

ggiraph(code = print(gg_crime),
        hover_css = "fill-opacity:.3;cursor:pointer;")