On flexdashboard, leafgl points are invisible until we pan or zoom

Question

Upon load, WebGL points are invisible until we pan or zoom. How can I make them visible immediately on load?

Upon load no points appear:

After pan or zoom points appear:

The code below can be pasted into an Rmd and knit:

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

```{r setup, include=TRUE}
library(flexdashboard)
library(leaflet)
library(leafgl)
library(sf)

n = 100

df1 = data.frame(id = 1:n,
                 x = rnorm(n, 10, 3),
                 y = rnorm(n, 49, 1.8))

pts = st_as_sf(df1, coords = c("x", "y"), crs = 4326)

leaflet() %>%
  addProviderTiles(provider = providers$CartoDB.DarkMatter) %>%
  addGlPoints(data = pts, group = "pts") %>%
  setView(lng = 10.5, lat = 49.5, zoom = 6)
```

Finally, my session info:

> sessionInfo()
R version 4.1.0 (2021-05-18)
Platform: x86_64-apple-darwin17.0 (64-bit)
Running under: macOS Catalina 10.15.7

Matrix products: default
BLAS:   /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
LAPACK: /Library/Frameworks/R.framework/Versions/4.1/Resources/lib/libRlapack.dylib

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils    
[5] datasets  methods   base     

other attached packages:
[1] sf_1.0-4            leafgl_0.1.1       
[3] leaflet_2.0.4.1     flexdashboard_0.5.2

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.7         compiler_4.1.0    
 [3] pillar_1.6.4       class_7.3-19      
 [5] tools_4.1.0        digest_0.6.28     
 [7] tibble_3.1.6       jsonlite_1.7.2    
 [9] evaluate_0.14      lifecycle_1.0.1   
[11] pkgconfig_2.0.3    rlang_0.4.12      
[13] DBI_1.1.1          crosstalk_1.2.0   
[15] xfun_0.28          fastmap_1.1.0     
[17] e1071_1.7-9        dplyr_1.0.7       
[19] knitr_1.36         generics_0.1.1    
[21] htmlwidgets_1.5.4  vctrs_0.3.8       
[23] tidyselect_1.1.1   classInt_0.4-3    
[25] grid_4.1.0         glue_1.5.0        
[27] R6_2.5.1           fansi_0.5.0       
[29] rmarkdown_2.11     purrr_0.3.4       
[31] magrittr_2.0.1     htmltools_0.5.2   
[33] ellipsis_0.3.2     units_0.7-2       
[35] assertthat_0.2.1   KernSmooth_2.23-20
[37] utf8_1.2.2         proxy_0.4-26      
[39] crayon_1.4.2 

Answer 1

As has been commented, There seems to be an issue with flexdashboard in R 4.1. It does work (on MacOS) with R 3.6. I'd suggest filing an issue on their GitHub repo.

Besides downgrading R, you could also "automatically" zoom in at the beginning and use flyTo() instead of setView().

Both solutions are rather hot fixes but I am afraid that the core problem must be fixed by flexdashboard itself.