Wish: support for rgl widget

[ugroempi]

Thanks for providing a framework for dashboards! I played with the html widgets example here and tried to replace the MetricsGraphics one with an rgl one:

library(rgl)
plot3d(mtcars$mpg, mtcars$disp, mtcars$hp,
xlab="miles per gallon", ylab="displacement", zlab="horse power", type="s", col=mtcars$cyl)
rglwidget()

This code works in Rmarkdown or bookdown, but does not work within the flexdashboard. I get the error message given below (German machine). It would be nice if rgl could be used in a flexdashboard.

Best, Ulrike

Here is the error message:
"Error in validateCssUnit(sizeInfo$width) : CSS units must be a single-element numeric or character vector"
"Ruft auf: ... -> need_screenshot -> toHTML -> validateCssUnit"

[dmurdoch]

I've just seen the same error. I'd be happy to modify rglwidget to work with flexdashboard, but I've no idea what modification would be needed. Any suggestions?

[jcheng5]

@dmurdoch It looks like your widget objects' x$width and x$height are numeric vectors of length 2 (returned from figWidth() and figHeight()), instead of the expected length 1.

[dmurdoch]

Yes, that's what's causing the problem. It's easy to work around, but I wonder if there's a deeper problem? In the example I was looking at, figHeight() was just rescaling the result of knitr::opts_current$get("fig.height"). That option is allowed to be a vector if you have multiple devices, but in this case the "dev" option is c( "png", "png"), so something looks like a bug.

[dmurdoch]

I've now put rgl 0.99.5 on R-forge with a fix for this.

[jcheng5]

Ah, the c("png", "png") appears to be intentional:

flexdashboard/R/flex_dashboard.R

Lines 247 to 262 in dd4440a

	if (identical(options$dev, 'png')) {
	figure_id <- paste0('fig', next_figure_id)
	options$dev <- c('png', 'png')
	options$fig.ext <- c('png', 'mb.png')
	options$fig.width <- c(options$fig.width, fig_mobile[[1]])
	options$fig.height <- c(options$fig.height, fig_mobile[[2]])
	options$out.extra <- c(options$out.extra, paste0('data-figure-id=',
	figure_id))
	options$fig.process <- function(filename) {
	if (grepl("^.*\\.mb\\.png$", filename)) {
	mobile_figures[[figure_id]] <<- filename
	next_figure_id <<- next_figure_id + 1
	}
	filename
	}
	}

Looks like it creates one PNG for desktop, and another PNG that's intended for mobile devices in portrait mode. This feature is specific to flexdashboard so it makes sense that this issue doesn't repro elsewhere.

Seems like mystery solved, so I'm closing the issue. Thanks for the report!