Cross referencing figures with html_letter

[NewGraphEnvironment]

First off - unreal package. Amazing! Game changer. Thank you so much.

For some reason I cannot seem to cross reference figures with html_letter. I can see that the figure caption will be a pop up in the html file but I would prefer it as a caption that I could cross reference in the text.

Interestingly, I have found a situation where it does work and that seems to be when the actual chunk output does not display. Sorry for the use of the DiagrammeR package in the example but it is the exception case I ran into so thought it might be relevant. Thank you!

---
title: "A letter of recommendation for Emi Tanaka"
author: "Yihui Xie"
output:
  pagedown::html_letter:
knit: pagedown::chrome_print
---
Any thoughts on how I might get Figure \@ref(fig:figure-1) to cross-reference like the failed output of Figure \@ref(fig:figure-2) does?

```{r figure-1, fig.cap='my_caption'}
knitr::include_graphics('https://www.rstudio.com/wp-content/uploads/2016/09/RStudio-Logo-Blue-Gray-250.png')

DiagrammeR::grViz("digraph rmarkdown{
graph[layout = dot, rankdir = LR]
d1 [label = 'step 1']
d2 [label = 'Step 2']
d1 -> d2 
}")

[RLesur]

Thanks a lot for this bug report.
This behavior comes from the fact that the html_letter output format modifies the defaut value of the fig_caption parameter and cannot be changed:

pagedown/R/paged.R

Lines 60 to 62 in f63b780

	html_letter = function(..., css = c('default', 'letter')) {
	html_paged(..., css = css, fig_caption = FALSE)
	}

This is undocumented, sorry for that.

[RLesur]

This is now fixed in the development version of pagedown. You can install this version with:

remotes::install_github("rstudio/pagedown")

In order to get figure references in html_letter you need to use

output:
  pagedown::html_letter:
    fig_caption: true

[NewGraphEnvironment]

👑