#install.packages("gg.gap")
library(gg.gap)

## Warning: package 'gg.gap' was built under R version 4.0.3

library(ggplot2)
data <-
  data.frame(x = c("Alpha", "Bravo", "Charlie", "Delta"),
             y = c(200, 20, 10, 15))
#plot
p1 = ggplot(data, aes(x = x, y = y, fill = x)) +
  geom_bar(stat = 'identity', position = position_dodge(),show.legend = FALSE) +
  theme_bw() +
  labs(x = NULL, y = NULL)

#p1 = p1 +  theme_classic()
p1

p2 = gg.gap(plot = p1,
            segments = c(25, 190),
            tick_width = 10,
            rel_heights = c(0.25, 0, 0.1),# set width
            ylim = c(0, 200))

p2

list(c(25,30),c(60,61))

## [[1]]
## [1] 25 30
## 
## [[2]]
## [1] 60 61

gg.gap(plot = p1,
            segments = list(c(25,30),c(60,61)),
            tick_width = c(10,5,20),
            rel_heights=c(0.2,0,0.2,0,0.2),
            ylim = c(0, 200))