How can I flip a mosaic plot in ggmosaic?

Question

How can I flip a mosaic plot in ggmosaic? For example, I want this:

to look like this:

Note "present" is on the top in the first plot and on the bottom in the second graph. I would like to make "present" on the bottom in the first plot.

The data is the "schizophrenia2" dataset from HSAUR3 package. Here is the code:

#import the data set
data("schizophrenia2", package="HSAUR3")
#plot in base R
library(vcd)
colors <- c("grey", "darkred")
mosaic(disorder ~ month | onset, highlighting_fill = colors, data = schizophrenia2, main = "Presence of Thought Disorder by Onset of Disease")
#plot in ggplot2
library(ggmosaic)
ggplot(data = schizophrenia2) + 
  geom_mosaic(aes(x = product(month, onset), fill=disorder), na.rm=T) +
  labs(title="Presence of Thought Disorder by Onset of Disease", x="Onset", y="Month") + 
  coord_flip() + 
  scale_fill_discrete(guide = guide_legend(reverse=TRUE), 
                      name="Disorder", labels=c("Absent", "Present", "Dropped Out"))

Note: vcd might stop working when you load ggmosaic. It did in mine. But I think I'm just missing some simple code in ggmosaic that would let me flip it.

Answer 1

The issue is the order that the levels of a variable are mapped in a ggplot2 object. You can achieve your desired result by reordering the onset and disorder variables.

#import the data set
data("schizophrenia2", package="HSAUR3")

#plot in ggplot2
library(ggmosaic)
library(dplyr)

schizophrenia2 %>% 
  mutate(onset = forcats::fct_relevel(onset, "> 20 yrs"),
         disorder = forcats::fct_relevel(disorder, "present")) %>% 
  ggplot() + 
  geom_mosaic(aes(x = product(month, onset), fill=disorder), na.rm=T) +
  labs(title="Presence of Thought Disorder by Onset of Disease") + 
  scale_x_productlist(name="Onset") +
  scale_y_productlist(name="Month") +
  coord_flip() +  
  scale_fill_discrete(guide = guide_legend(reverse=TRUE), 
                      name="Disorder", labels=c("Present", "Absent", "Dropped Out"))