geom_text at certain position in a pie chart - r

Question

I want to create a pie chart with some labels displayed at certain location signifying whether a proportion test is significant or not. I have managed to create a basic pie chart and I have pasted the code below. I have also posted the desired result (created using MS Paint software) and would love any help I can get any creating this plot.
library(tidyverse)
# defining the dataframe
df <-
data.frame(
condition = c('x', 'y', 'z'),
cat = rep(c('a', 'b'), 3),
freq = c(60, 34, 44, 40, 66, 56)
)
# computing percentages
df <-
df %>% group_by(condition) %>% mutate(label = freq / sum(freq) * 100)
# creating a pie chart
ggplot2::ggplot(data = df, mapping = aes('', freq, fill = cat)) +
facet_grid(". ~ condition") +
geom_col(position = 'fill') +
geom_label(aes(label = label), position = position_fill(vjust = 0.5)) +
coord_polar(theta = 'y') +
ggplot2::scale_y_continuous(breaks = NULL) +
ggplot2::theme_grey() +
ggplot2::theme(
panel.grid = element_blank(),
axis.ticks = element_blank(),
axis.title = element_blank(),
axis.text.x = element_blank(),
axis.text.y = element_blank(),
strip.text.x = element_text(size = 14, face = "bold"),
strip.text.y = element_text(size = 14, face = "bold"),
strip.text = element_text(size = 14, face = "bold"),
legend.text = element_text(size = 14),
legend.title = element_text(size = 14, face = "bold"),
legend.title.align = 0.5,
legend.text.align = 0.5,
legend.direction = "horizontal",
legend.position = "bottom",
legend.key = element_rect(size = 5),
legend.key.size = unit(1.5, "lines"),
legend.margin = margin(5, 5, 5, 5),
legend.box.margin = margin(5, 5, 5, 5),
panel.border = element_rect(
colour = "black",
fill = NA,
size = 1
),
plot.subtitle = element_text(
color = "black",
size = 14,
hjust = 0.5
),
plot.title = element_text(
color = "black",
size = 16,
face = "bold",
hjust = 0.5
)
) +
ggplot2::guides(fill = guide_legend(override.aes = base::list(colour = NA)))
Created on 2018-03-21 by the reprex package (v0.2.0).
Here is what the desired result looks like (notice that the text is always at the top and aligned to the center of the pie chart)-

Answer 1

How about this? I used geom_text and specified x = 1.6 to get labels outside the radius of the pie chart. Also, just a style tip, but you have a lot of unnecessary arguments in theme(), and you don't need to put ggplot2:: before ggplot functions after loading the tidyverse. Also, if you'd like the pie chart to not have a small empty dot in the center of it, you can put width = 1 in your call to geom_col.
library(tidyverse)
df <-
data.frame(
condition = c('x', 'y', 'z'),
cat = rep(c('a', 'b'), 3),
freq = c(60, 34, 44, 40, 66, 56),
sig =c("***", NA, "ns", NA, "**", NA)
) %>%
group_by(condition) %>%
mutate(label = freq / sum(freq) * 100)
ggplot(data = df, mapping = aes('', freq, fill = cat)) +
facet_wrap(~ condition, nrow = 1) +
geom_col(position = 'fill', width = 1) +
geom_label(aes(label = label), position = position_fill(vjust = 0.5)) +
geom_text(aes(label = sig, x = 1.6), position = position_fill(vjust = 1)) +
coord_polar(theta = 'y') +
theme_grey() +
theme(panel.grid = element_blank(),
axis.ticks = element_blank(),
axis.text = element_blank(),
axis.title = element_blank(),
strip.text = element_text(size = 14, face = "bold"),
strip.background = element_rect(color = "black", size = 1),
legend.text = element_text(size = 14),
legend.title = element_text(size = 14, face = "bold"),
legend.position = "bottom",
legend.key.size = unit(1.5, "lines"),
panel.border = element_rect(colour = "black", fill = NA, size = 1)) +
guides(fill = guide_legend(override.aes = list(colour = NA)))
Here's the result