How to create a Marimekko/Mosaic plot in ggplot2

Question

The Marimekko/Mosaic plot is a nice default plot when both x and y are categorical variables. What is the best way to create these using ggplot?

Answer 1

Following user2030503's suggestion, here's a version that uses ggmosaic. (Note that ggplot 3.0 broke some piece of ggmosaic, so you need the most recent version.)

library(tidyverse)
library(ggmosaic)

# Data copied from linked blog post
df <- data.frame(
  segment = LETTERS[1:4],
  segpct = c(40, 30, 20, 10),
  Alpha = c(60, 40, 30, 25), 
  Beta = c(25, 30, 30, 25),
  Gamma = c(10, 20, 20, 25), 
  Delta = c(5, 10, 20, 25)
  )

# Convert to "long" for plotting
df_long <- gather(df, key = "greek_letter", value = "pct", 
                  -c("segment", "segpct")) %>% 
  mutate(
    greek_letter = factor(
      greek_letter, 
      levels = c("Alpha", "Beta", "Gamma", "Delta")
      ),
    weight = (segpct * pct) / 10000
    )

# Plot
ggplot(df_long) +
  geom_mosaic(aes(x = product(greek_letter, segment), fill = greek_letter,
                  weight = weight))