Make plotly annotation font bold

Question

I'd like to add annotation to a scatter plot generated by R's plotly package, and have the text appear in bold.

I'm trying:

library(plotly)
library(dplyr)

set.seed(1)
df <- data.frame(x=rnorm(10),y=rnorm(10))
plotly::plot_ly(x =~ df$x, y =~ df$y,marker = list(size=12), type = 'scatter',mode = "markers") %>%
  plotly::add_annotations(text=1:10,showarrow=T,arrowhead=1,x=df$x,y=df$y,font=list(size=10))

Which gives:

Trying to add face="bold" to the font specification list:

plotly::plot_ly(x =~ df$x, y =~ df$y,marker = list(size=12), type = 'scatter',mode = "markers") %>%
  plotly::add_annotations(text=1:10,showarrow=T,arrowhead=1,x=df$x,y=df$y,font=list(size=10,face="bold"))

Doesn't really change anything:

So the question is how to get that text annotation to appear in bold.

P.S. In my real data I'd like to annotate clusters of points hence the annotations come as a separate layer.

Answer 1

Simply enter your text as HTML, like so:

plotly::plot_ly(x =~ df$x, y =~ df$y,marker = list(size=12), type = 'scatter',mode = "markers") %>%
  plotly::add_annotations(text=sprintf("<b>%s</b>", 1:10),showarrow=T,arrowhead=1,x=df$x,y=df$y,font=list(size=10))