TidyTuesday: Roman Emperors by Wikipedia

## packages
library(tidyverse)
library(lubridate)
library(ggrepel)
library(showtext)

## ggplot theme updates
source(here::here("R", "tidy_grey.R"))
theme_update(line = element_blank(),
             rect = element_rect(fill = "#f7f5ee", color = "transparent"),
             panel.border = element_blank(),
             axis.text = element_blank(),
             plot.title = element_text(color = "black", hjust = 0.5, size = 30),
             plot.subtitle = element_text(color = "grey30", hjust = 0.5, 
                                          size = 8, margin = margin(0, 0, 0, 0)),
             plot.caption = element_text(color = "grey30", size = 8))

## add fonts via showtext
font_add_google("Cinzel", "Cinzel")
showtext_auto()

df_emperors <- readr::read_csv("https://raw.githubusercontent.com/rfordatascience/tidytuesday/master/data/2019/2019-08-13/emperors.csv") %>% 
  mutate(
    birth = case_when(
      index %in% c(1, 2, 4, 6) ~ update(birth, year = -year(birth)),
      TRUE ~ birth
    ),
    reign_start = case_when(
      index == 1 ~ update(reign_start, year = -year(reign_start)),
      TRUE ~ reign_start
    )
  )

## 
## -- Column specification --------------------------------------------------------
## cols(
##   index = col_double(),
##   name = col_character(),
##   name_full = col_character(),
##   birth = col_date(format = ""),
##   death = col_date(format = ""),
##   birth_cty = col_character(),
##   birth_prv = col_character(),
##   rise = col_character(),
##   reign_start = col_date(format = ""),
##   reign_end = col_date(format = ""),
##   cause = col_character(),
##   killer = col_character(),
##   dynasty = col_character(),
##   era = col_character(),
##   notes = col_character(),
##   verif_who = col_character()
## )

labs_yrs <- tibble(x = rep(5, 10),
                   time = c(-50, 1, seq(50, 400, by = 50))) %>% 
  mutate(
    jesus = ifelse(time < 0, "BC", "AD"),
    lab = glue::glue("{time} {jesus}")
  )
  
legend <- tibble(
  y = c(-50, -46, -42),
  text = c("Natural Death in Peace", 
           "Fatality or in Captivity", 
           "Unknown Cause of Death")
)

df_emperors %>% 
  mutate(
    reign_start = lubridate::year(reign_start),
    cause = case_when(
      cause == "Natural Causes" ~ "Natural Death in Peace",
      cause == "Unknown" ~ "Unknown Cause of Death",
      TRUE ~ "Fatality or in Captivity"
    ),
    cause = fct_relevel(cause, "Natural Death in Peace", 
                                "Fatality or in Captivity", 
                                "Unknown Cause of Death")
  ) %>% 
  ggplot(aes(x = 1.6, y = reign_start)) + 
    geom_segment(data = labs_yrs, aes(x = 1.6, xend = 1.7, y = time, yend = time), 
                 size = 0.5, color = "grey30") +
    geom_segment(x = 1.6, xend = 1.6, y = 55, yend = -405, lineend = "round", 
                 size = 2.5, color = "grey30") +
    geom_text_repel(aes(label = name, color = cause), segment.color = "grey60",
                    segment.size = 0.1, family = "Cinzel", fontface = "bold",
                    size = 3.8, xlim  = c(0, 1.1), hjust = 1) +
    geom_point(color = "transparent", fill = "white", size = 5, shape = 21) +
    geom_point(color = "grey30", fill = alpha("grey10", 0.1), size = 5, shape = 21) +
    geom_text(data = labs_yrs, aes(x = 1.72, y = time, label = lab), 
              family = "Cinzel", hjust = 0, color = "grey30") + 
    geom_text(data = legend, aes(x = 0.75, y = y, label = text, color = text), 
              family = "Cinzel", hjust = 0.5, size = 3.2) + 
    scale_x_continuous(limits = c(0, 2.3)) +
    scale_y_reverse(limits = c(400, -50)) +
    scale_color_manual(values = c("#b26a22", "#b22222", "grey50"), guide = F) +
    theme(plot.title = element_text(family = "Cinzel"),
          plot.subtitle = element_text(family = "Cinzel")) +
    labs(x = NULL, y = NULL, title = "The Emperors of Rome",
         subtitle = "\nTimeline of roman emperors, start of each reign and their cause of death.\nThe darker the circles, the more emperors were reigning during this period.",
         caption = "\nVisualization by Dinesh Mahapatra  |  Data: Wikipedia")

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