How to change background color in ggvis?

Question

require(ggvis)
require(dplyr)
map_data = ggplot2::map_data("world")
map_data %>% select(long, lat, group) %>%
  group_by(group) %>%
  ggvis(x = ~long, y = ~lat) %>% layer_paths(fill:="#666666") %>%
  hide_axis("x") %>% hide_axis("y")

That produces a nice map, but I'd like control over the "ocean" color (e.g. "black"). How to do that?

More generally, the ocean color is the plot default background.

Answer 1

Adding a layer_rects seems to have done it:

require(ggvis)
require(dplyr)
map_data = ggplot2::map_data("world")
minx = min(map_data$long -1)
maxx = max(map_data$long +1)
miny = min(map_data$lat - 1)
maxy = max(map_data$lat + 1)
map_data %>% select(long, lat, group) %>%
  group_by(group) %>%
  ggvis(x = ~long, y = ~lat) %>% 
  layer_rects(x=minx, x2=maxx, y=maxy, y2=miny, fill:="#000000") %>%
  layer_paths(fill:="#666666") %>%
  hide_axis("x") %>% hide_axis("y")