Leaflet draw on projected map in R

Thanks to Bhaskar!

https://github.com/bhaskarvk/leaflet.extras

Here we use a shaded background from https://maps.environments.aq.

library(leaflet.extras)
## Loading required package: leaflet
library(dplyr)
## 
## Attaching package: 'dplyr'
## The following objects are masked from 'package:stats':
## 
##     filter, lag
## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union
zoom <- 1
maxZoom <- 5


crsAntartica <-  leafletCRS(
  crsClass = 'L.Proj.CRS',
  code = 'EPSG:3031',
  proj4def = '+proj=stere +lat_0=-90 +lat_ts=-71 +lon_0=0 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs',
  resolutions = c(8192, 4096, 2048, 1024, 512, 256),
  origin = c(-4194304, 4194304),
  bounds =  list( c(-4194304, -4194304), c(4194304, 4194304) )
)

leaflet(options= leafletOptions(crs=crsAntartica, minZoom = zoom, maxZoom=maxZoom, worldCopyJump = FALSE)) %>%
  setView(0, -90, 0) %>%
  addDrawToolbar(
    group='draw',

    editOptions = editToolbarOptions(selectedPathOptions = selectedPathOptions()))  %>%
  addLayersControl(overlayGroups = c('draw'), options =
                     layersControlOptions(collapsed=FALSE)) %>%
  addStyleEditor() %>% 
  addWMSTiles(baseUrl="https://maps.environments.aq/mapcache/antarc/?",
              layers="antarc_ramp_bath_shade_mask",
              options=WMSTileOptions(format="image/png",transparent=TRUE),
              attribution="") %>%
  addGraticule()