Heat map with numbers in ggvis

Question

I'm trying to replicate the heat map with numbers from ggplot2 in ggvis. ggplot2 version is

library(ggplot2)
hec <- as.data.frame(xtabs(Freq ~ Hair + Eye, HairEyeColor))
ggplot(hec, aes(Hair, Eye)) +
geom_tile(aes(fill = Freq)) + 
geom_text(aes(label = Freq),colour="white") 

and it looks like that

My version in ggvis is

hec%>%
ggvis(~Hair, ~Eye, fill=~Freq)%>%
layer_rects(width = band(), height = band()) %>%
layer_text(text:=~Freq,fontSize := 20, fill:="white",baseline:="top",align:="center") %>%
scale_nominal("x", padding = 0, points = FALSE) %>%
scale_nominal("y", padding = 0, points = FALSE) 

and the result is not perfect

I've tried to fix numbers align by manually adding margins, but this case is not resizeable.

Any ideas?

Answer 1

One workaround is to use xcenter and ycenter scales:

hec <- as.data.frame(xtabs(Freq ~ Hair + Eye, HairEyeColor))

hec%>%
  ggvis(~Hair, ~Eye, fill=~Freq) %>%
  layer_rects(width = band(), height = band()) %>%
  layer_text(
    x = prop("x", ~Hair, scale = "xcenter"),
    y = prop("y", ~Eye, scale = "ycenter"),
    text:=~Freq, fontSize := 20, fill:="white", baseline:="middle", align:="center") %>%
  scale_nominal("x", padding = 0, points = FALSE) %>%
  scale_nominal("y", padding = 0, points = FALSE) %>% 
  scale_nominal("x", name = "xcenter", padding = 1, points = TRUE) %>%
  scale_nominal("y", name = "ycenter", padding = 1, points = TRUE)