Monchrome Pie/Donut Chart

Why would you ever want to use a pie chart…?

Sample Data

types <- c("Footwear","Apparel","Equipment","Miscellaneous")
factor_types <- factor(types, levels=types)

sales <- data.frame(type = factor_types,
                    num_sales = c(7947,3237,387,48)) %>%
  mutate(percent_sales = scales::percent(num_sales/sum(num_sales)))

Color Palette

base_color <- "#41598b"
saturation_diff <- 1/(length(types)-1) 
# evenly space out the palette based on the number of categories
# the color will be hard to tell apart if there are too many categories!!

# this function is adapted from Josh O'Brien's answer on #
# https://stackoverflow.com/questions/26314701/r-reducing-colour-saturation-of-a-colour-palette

desaturate_by <- function(colors, by) {
    X <- diag(c(1, by, 1)) %*% rgb2hsv(col2rgb(colors))
    hsv(X[1,], X[2,], X[3,])
}

palette <- sapply(seq(1,0,-saturation_diff),
              function(x){desaturate_by(base_color,x)})

Plot

plotDONUT <- as.double(TRUE)  # set to FALSE for a pie chart
width <- 0.5  # width of the donut (relative to the radius), does not affect the pie chart
text_dist <- plotDONUT + width/2 + 0.3 # distance of the labels from the center of the donut; the last term is the distance from the edge

ggplot(data = sales,
       aes(x=plotDONUT, y=num_sales, fill=type, xmax=plotDONUT+width, xmin=0))+
  geom_bar(stat="identity", width=width) +
  scale_fill_manual(values=palette, breaks=factor_types)+
  # the stacked bar chart starts from the top, hence the rev():
  geom_text(aes(x= text_dist,
                y=cumsum(rev(num_sales))-rev(num_sales)/2,
                label=rev(percent_sales)),
            size=5,
            nudge_y=c(0,0.03,0,0)*sum(sales$num_sales)) +
            # adjust the nudge_y to avoid overlaps;
            # do not use position_jitter(), as it will cause gaps in the chart
            # a less painstaking solution is to use ggrepel::geom_text_repel()
  coord_polar(theta="y", start=0) +
  labs(fill="", title="Breakdown of the Revenue") +
  theme_void()