ggtree+ggplotly: show custom images on hover

[Ales Bucek]

Dear Yu,

I'm trying to use combination of ggtree and ggplotly for interactive phylogenies.

The ggtree package is apparently not fully supported by plotly (https://github.com/ropensci/plotly/issues/566) - i.e. not supported geoms, but it still feels like a very powerful tool to share phylogenies and rich metadata associated with the phylogenies.

1st question: Did you previously try to use ggplotly with ggtree and would you consider writing a tutorial on combination of these two? I'd be happy to help.

2nd question: One feature I'm trying to test is a photo of species shown when hovering over the respective tip.

I can do this as in example below:

library(dplyr)
library(ggtree)
library(plotly)

#obtain image

download.file("https://upload.wikimedia.org/wikipedia/commons/thumb/1/1b/R_logo.svg/200px-R_logo.svg.png", "Rlogo.png")
Rlogo <- base64enc::dataURI(file = sprintf("Rlogo.png"))

#plot tree

nwk <- system.file("extdata", "sample.nwk", package="treeio")
tree <- read.tree(nwk)
p <- ggtree(tree)

#generate vector of tip coordinates
xcoords <- subset(p$data, isTip==TRUE)$x
ycoords <- subset(p$data, isTip==TRUE)$y

#generate interactive plot
p %>% ggplotly() %>%
  add_text(inherit=FALSE, x=xcoords, y=ycoords, customdata = Rlogo, text = FALSE) %>%
  htmlwidgets::onRender(readLines("tooltip-image.js"))

But this fails when I add geom_point() to the tree, because the only the node information is shown on hover instead of trigerring the on-hover action to render the image.

p <- ggtree(tree)+geom_point()
p %>% ggplotly() %>%
  add_text(inherit=FALSE, x=xcoords, y=ycoords, customdata = Rlogo, text = FALSE) %>%
  htmlwidgets::onRender(readLines("tooltip-image.js"))

Ideally, I would like to show both the node information and also an associated image data on hover. While this is a very specific question I'm in general interested some recommended practises could be formulate how to combine ggtree and ggplotly.

Thanks for any suggestions!

Ales