ggpattern missing pattern after na values - r

Question

Using ggpattern, how can I not show a pattern for "NA" values but then have patterns continue after that point? When I run this code, there are no more patterns after an "NA" value even though there should be.
library(swimplot)
library(ggpattern)
library(tidyverse)
df <- data.frame(
study_id = c(3, 3, 3,3), primary_therapy = c("Si", "Si", "Si", "Si"),
additional_therapy = c("NA", "S", "NA", "V+S"), end_yr = c(0.08, 0.39, 3.03, 3.4)
)
swimmer_plot(
df = df, id = "study_id",
end = "end_yr", name_fill = "primary_therapy",
width = 0.85, color = NA) +
geom_col_pattern(aes(study_id, end_yr,
pattern = additional_therapy), color=NA,
fill = NA,
show.legend=FALSE, width=0.85,
pattern_spacing = 0.01, pattern_fill="black", pattern_color=NA,
pattern_size = 0.5, pattern_density=0.1,
pattern_linetype = 0.5, pattern_orientation="vertical") +
scale_pattern_manual(name="Additional Therapy", values = c("S"="stripe","V"="circle","V+S"="crosshatch","NA"="none"))

Answer 1

Your question has two parts: 1) controlling the legend labels and 2) fixing the x-axis for geom_col_pattern().
For your first question, you can remove "NA" from the legend by converting additional_therapy to a factor:
df <- df %>%
mutate(additional_therapy = factor(additional_therapy,
levels = c("S", "V", "V+S", "NA")))
Then, you can specify breaks to control which legend labels show up:
+ scale_pattern_manual(name="Additional Therapy", breaks = c("S", "V", "V+S"), values = c("S"="stripe", "V"="circle", "V+S"="crosshatch", "NA"="none"))
However, to the best of my knowledge, there is a problem with ggpattern when it comes to repeating patterns. I was able to recreate this issue using base ggplot2 to confirm that it's not an issue with swimplot.
In the below code, you can see that fill acts appropriately, but pattern will never repeat twice, which causes the pattern from "S" to spill over into the second red bar, which shouldn't have any pattern because it's "NA". I recommend submitting an issue on Github.
library(ggpattern)
library(tidyverse)
df <- data.frame(
study_id = c(3, 3, 3, 3), primary_therapy = c("Si", "Si", "Si", "Si"),
additional_therapy = c("NA", "S", "NA", "V+S"), end_yr = c(0.08, 0.39, 3.03, 3.4))
df %>%
ggplot(aes(x = end_yr, y = study_id)) +
geom_col_pattern(aes(pattern = additional_therapy,
fill = additional_therapy),
color = NA,
show.legend = TRUE,
position = "fill",
width = 3,
pattern_spacing = 0.01,
pattern_fill = "black",
pattern_color = NA,
pattern_size = 0.5,
pattern_density = 0.1,
pattern_linetype = 0.5,
pattern_orientation = "vertical") +
scale_pattern_manual(
name = "Additional Therapy",
breaks = c("S", "V", "V+S"),
values = c("S" = "stripe", "V" = "circle", "V+S" = "crosshatch", "NA" = "none"))