tm_minimap() not working unless leaflet is loaded

[mtennekes]

Just before going to submit tmap(tools) 2.0 to CRAN, I found this bug:

library(tmap)
qtm()  # shortcut for tm_basemap() + tm_minimap(), which automatically switches to view mode

throws this error, while

library(tmap)
library(leaflet)
qtm()

works.

The call traceback of the error is:

Error in tiles %in% providers : object 'providers' not found 
8.
tiles %in% providers 
7.
(function (map, position = "bottomright", width = 150, height = 150, 
    collapsedWidth = 19, collapsedHeight = 19, zoomLevelOffset = -5, 
    zoomLevelFixed = FALSE, centerFixed = FALSE, zoomAnimation = FALSE, 
    toggleDisplay = FALSE, autoToggleDisplay = FALSE, minimized = FALSE,  ... 
6.
do.call(addMiniMap, c(list(map = lf), mmargs)) at view_tmap.R#653
5.
view_tmap(x, shps = list(dummy = NULL)) at print_tmap.R#120
4.
print_shortcut(x, interactive, args, knit) at print_tmap.R#341
3.
print_tmap(x = x, vp = vp, return.asp = return.asp, mode = mode, 
    show = show, knit = knit, options = options, ...) at print_tmap.R#40
2.
print.tmap(x) 
1.
function (x, ...) 
UseMethod("print")(x) 

The list object providers is not exported by leaflet (i.e. it is not in its NAMESPACE), but made accessible with this dirty (but working) hack:

utils::globalVariables(c("providers")) # To make R CMD Check happy

See https://github.com/rstudio/leaflet/blob/master/R/plugin-minimap.R#L1. Therefore, the providers object can be accessed with leaflet::providers.

Does anyone has a clue how to use addMinimap inside a package? It is called here: https://github.com/mtennekes/tmap/blob/master/R/view_tmap.R#L653 @tim-salabim : do you use minimaps or the providers object in mapview?

[tim-salabim]

Nope for both. Minimap is neat but doesn't really add any value for quick layer inspection. Regarding providers, I call addProviderTiles("XXX") directly, e.g. "CartoDB.Positron"

[mtennekes]

I think it's a nice feature, especially in unfamiliar areas.

I made a pull request in leaflet, as you can see above. For now, a message "please load leaflet" is shown when tm_minimap doesn't work. Also I changed the default value of qtm.minimap to FALSE.