How to plot a zoom of the plot inside the same plot area using ggplot2?

Question

This question seems difficult to understand, but to illustrate, I bring a figure as an example:

I am trying to replicate this graph. So far I've done the graphics separately, but I don't know how I can put them together as in the example.

Any help?

time <- seq(from = 0,
            to = 10,
            by = 0.5)

line_1 <- c(0, 0, 0, 66, 173, 426, 1440, 800, 1200, 400, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
line_2 <- c(0, 0, 0, 0, 0, 0, 0, 0, 1000, 25000, 5000, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)

df <- data.frame(time, line_1, line_2)

library(ggpubr)

#the plot
ggplot(data = df, aes(x = time)) +
  geom_line(aes(y = line_2), color = "red",
            position = position_nudge(x = 0.5, y = 1000)) +
  geom_line(aes(y = line_1),color = "blue") +
  geom_rect(aes(xmin = 1, xmax = 5, ymin = 0, ymax = 1500), color = "black", alpha = 0) +
  theme_pubr( base_size = 8,
              border = TRUE)

#The plot with a zoom
ggplot(data = df, aes(x = time, y = line_1)) +
  geom_line(color = "blue") +
  xlim (1, 5) +
  ylim (0, 1500) +
  theme_pubr( base_size = 8,
              border = TRUE)

Answer 1

You can use a custom annotation

p1 = ggplot(data = df, aes(x = time)) +
  geom_line(aes(y = line_2), color = "red", position = position_nudge(x = 0.5, y = 1000)) +
  geom_line(aes(y = line_1),color = "blue") +
  geom_rect(aes(xmin = 1, xmax = 5, ymin = 0, ymax = 1500), color = "black", alpha = 0) +
  theme_pubr( base_size = 8, border = TRUE)

#The plot with a zoom
p2 = ggplot(data = df, aes(x = time, y = line_1)) +
  geom_line(color = "blue") +
  xlim (1, 5) +
  ylim (0, 1500) +
  theme_pubr( base_size = 8,border = TRUE)

p1 + 
  annotation_custom(ggplotGrob(p2), xmin = 0, xmax = 4, ymin = 5000, ymax = 20000) +
  geom_rect(aes(xmin = 0, xmax = 4, ymin = 5000, ymax = 20000), color='black', linetype='dashed', alpha=0) +
  geom_path(aes(x,y,group=grp), 
            data=data.frame(x = c(1,0,5,4), y=c(1500,5000,1500,5000),grp=c(1,1,2,2)),
            linetype='dashed')

Answer 2

@dww's answer inspired me to write a little package:

devtools::install_github("hughjonesd/ggmagnify")
install.packages(c("ggfx", "ggforce")

ggplot(data = df, aes(x = time)) +
  geom_line(aes(y = line_2), color = "red",
            position = position_nudge(x = 0.5, y = 1000)) +
  geom_line(aes(y = line_1),color = "blue") + 
  geom_magnify(from = c(1, 0, 5, 1500), 
               to = c(0, 10000, 2.5, 20000), 
               shadow = TRUE)

Theme at will.