Center geom_text on ggplot while controlling bar width - r

Question

I am trying to make a horizontal bar chart in ggplot2 where the bars are of equal width and with text labels centered on the bars. There are two groups on the y axis -- one with 2 bars, and one with three.
There are a lot of similar questions on SO that address both of these issues, but I haven't been able to fix one without breaking the other. Here's my data:
## data
df <- tibble(var1 = c("a", "b", "b", "c", "c"),
var2 = c("x", "y", "x", "y", "x"),
proportion = c(100, 33.3, 66.7, 66.7, 33.3)) %>%
mutate(var1 = factor(var1, levels = var1_order))
var1_order <- c("a", "c", "b")
Here's an example where the widths are good, but the labels of the y group are off:
## labels bad
df %>%
ggplot(aes(x = proportion, y = var2, fill = var1,
label = paste0(round(proportion, 1), "%"))) +
geom_col(position = position_dodge2(preserve = "single", padding = 0), width = .9) +
geom_text(size = 3, position = position_dodge2(width = 0.9), hjust = -.5,
color = "black", aes(group = var1)) +
scale_fill_manual(name = "", values = c("#093D6E","#5D8AA8", "#00918B",
"#F8AF54", "#CD9575")) +
labs(x = NULL) +
theme(axis.ticks = element_blank(),
axis.title.y = element_blank(),
axis.line=element_blank(),
axis.text.x = element_blank(),
panel.background = element_blank(),
strip.text = element_text(size = 7, face = "bold")) +
scale_x_continuous(expand = c(.2, .2)) +
guides(fill = guide_legend(reverse = TRUE))
And here's an example where the labels are good but the widths are now off:
## col widths bad
df %>%
ggplot(aes(x = proportion, y = var2, fill = var1,
label = paste0(round(proportion, 1), "%"))) +
geom_col(position = position_dodge(width = 0.9)) +
geom_text(size = 3, position = position_dodge(width = 0.9), hjust = -.5,
color = "black", aes(group = var1)) +
scale_fill_manual(name = "", values = c("#093D6E","#5D8AA8", "#00918B",
"#F8AF54", "#CD9575")) +
labs(x = NULL) +
theme(axis.ticks = element_blank(),
axis.title.y = element_blank(),
axis.line=element_blank(),
axis.text.x = element_blank(),
panel.background = element_blank(),
strip.text = element_text(size = 7, face = "bold")) +
scale_x_continuous(expand = c(.2, .2)) +
guides(fill = guide_legend(reverse = TRUE))
Note that this will be part of a parameterized report, so it needs to be capable of dealing with different numbers of var1 and var2 groups. Thanks!

Answer 1

Try this approach. You can use position_dodge2() to keep uniform bars. Here the code:
library(ggplot2)
#Code
df %>%
ggplot(aes(x = proportion, y = var2, fill = var1,
label = paste0(round(proportion, 1), "%"))) +
geom_col(position = position_dodge2(preserve = 'single',width = 0.9)) +
geom_text(size = 3, position = position_dodge2(preserve = 'single',width = 0.9), hjust = -.5,
color = "black", aes(group = var1)) +
scale_fill_manual(name = "", values = c("#093D6E","#5D8AA8", "#00918B",
"#F8AF54", "#CD9575")) +
labs(x = NULL) +
theme(axis.ticks = element_blank(),
axis.title.y = element_blank(),
axis.line=element_blank(),
axis.text.x = element_blank(),
panel.background = element_blank(),
strip.text = element_text(size = 7, face = "bold")) +
scale_x_continuous(expand = c(.2, .2)) +
guides(fill = guide_legend(reverse = TRUE))
Output: