Animations

class: center, middle, title-slide

.title[
# Animations
]
.author[
### Claus O. Wilke
]
.date[
### last updated: 2024-04-22
]

---

## Animations can create more engaging displays

.center.move-up-1em[
<img src="animations_files/figure-html/gdp-anim-bar-race-1.gif" width="50%" />
]

.absolute-bottom-right.tiny-font[
Data source: World Bank
]

---

## Animations can create more engaging displays

.center[
<img src="animations_files/figure-html/gdp-anim-lines-race-1.gif" width="66%" />
]

.absolute-bottom-right.tiny-font[
Data source: World Bank
]

---

## We make animations in R with **gganimate**

.width-70[
```r
library(tidyverse)
library(gganimate)

# make fun animations
...
```
]

The **gganimate** package adds powerful animation tools to **ggplot2**

---

## Getting the data

We'll be working with the `gdp_ranked` dataset:

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```r
gdp_ranked <- read_csv("https://wilkelab.org/SDS375/datasets/gdp_ranked.csv") %>%
  mutate(rank = fct_rev(factor(rank)))

gdp_ranked
```

```
# A tibble: 500 × 6
   country country_code  year   gdp rank  gdp_rel
   <chr>   <chr>        <dbl> <dbl> <fct>   <dbl>
 1 Brazil  BRA           1970  42.3 10     0.0395
 2 Brazil  BRA           1971  49.2 10     0.0424
 3 Brazil  BRA           1972  58.5 10     0.0457
 4 Brazil  BRA           1973  79.3 10     0.0555
 5 Brazil  BRA           1974 105   9      0.0677
 6 Brazil  BRA           1975 124   9      0.0738
 7 Brazil  BRA           1976 153   9      0.0818
 8 Brazil  BRA           1977 176   8      0.0846
 9 Brazil  BRA           1978 201   8      0.0855
10 Brazil  BRA           1979 225   8      0.0856
# ℹ 490 more rows
```
]

---
class: center middle

## How should we think about making an animation?

---

## Think of an animation as faceting by time

.center.move-up-1em[
<img src="animations_files/figure-html/gdp-anim-bar-facets-1.svg" width="80%" />
]

---

## We know how to make a faceted plot

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```r
gdp_ranked %>%
  filter(year > 1985 & year %% 5 == 0) %>%
  ggplot(aes(gdp, rank)) +
  geom_col(aes(fill = country)) +
  facet_wrap(~year)
```
]

.center[
<img src="animations_files/figure-html/gdp-facet-demo-out-1.svg" width="50%" />
]

---

## Making an animation is about as complicated

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```r
gdp_ranked %>%
  # gganimate uses the `group` aesthetic to track objects across frames
  ggplot(aes(gdp, rank, group = country)) + 
  geom_col(aes(fill = country)) +
  transition_states(year, transition_length = 5)
```
]

.center[
<img src="animations_files/figure-html/gdp-bar-race-demo-1.gif" width="40%" />
]

---

## Adding country names and plot title

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```r
gdp_ranked %>%
  ggplot(aes(gdp, rank, group = country)) +
  geom_col(aes(fill = country)) +
  geom_text(
    aes(x = -200, label = country),
    hjust = 1, size = 14/.pt
  ) +
  xlim(-7000, 23000) +
  labs(title = "year: {closest_state}") +
  theme_minimal_vgrid(14, rel_small = 1) +
  theme(
    axis.text.y = element_blank(),
    axis.title.y = element_blank(),
    axis.ticks.y = element_blank(),
    axis.line.y = element_blank()
  ) + 
  guides(fill = "none") +
  transition_states(year, transition_length = 5)
```
]

.pull-right.width-40[
<img src="animations_files/figure-html/gdp-anim-fancy-out-1.gif" width="100%" />
]

---

## We make time series with `transition_reveal()`

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```r
selected <- c("China", "Japan",
  "United States", "Germany", "Brazil")

gdp_ranked %>%
  filter(country %in% selected) %>%
  ggplot(aes(year, gdp, color = country)) +
  geom_line() +
  geom_point(size = 3) +
  scale_y_log10() +
  transition_reveal(year)
```
]

.pull-right.width-45[
<img src="animations_files/figure-html/gdp-line-race-demo-out-1.gif" width="100%" />
]

---

## This works also with **ggrepel** for labeling

.tiny-font.pull-left.width-50[

```r
gdp_ranked %>%
  filter(country %in% selected) %>%
  ggplot(aes(year, gdp, color = country)) +
  geom_line() +
  geom_point(size = 3) +
  geom_text_repel(
    aes(label = country),
    hjust = 0,
    nudge_x = 2,
    direction = "y",
    xlim = c(NA, Inf),
    segment.color = NA
  ) +
  scale_y_log10() +
  guides(color = "none") +
  coord_cartesian(clip = "off") +
  theme(plot.margin = margin(7, 100, 7, 7)) +
  transition_reveal(year)
```
]

.pull-right.width-45[
<img src="animations_files/figure-html/gdp-line-race-labeled-out-1.gif" width="100%" />
]

---

## Reproducing the famous gapminder animation

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```r
library(gapminder)

gapminder %>% filter(continent != "Oceania") %>%
  ggplot() +
  aes(gdpPercap, lifeExp, size = pop) +
  geom_point(alpha = 0.7, color = "#0072B2") +
  scale_size(range = c(2, 12), guide = "none") +
  scale_x_log10(name = "GDP per capita") +
  facet_wrap(~continent, nrow = 2) +
  labs(
    title = "Year: {frame_time}",
    y = "life expectancy"
  ) +
  transition_time(year) +
  ease_aes("linear")
```

See Hans Rosling [video here.](https://www.youtube.com/watch?v=jbkSRLYSojo)

]

.pull-right.width-45[
<img src="animations_files/figure-html/gapminder-bubbles-out-1.gif" width="100%" />
]

---

## Further reading

- **gganimate** documentation: [Getting started](https://gganimate.com/articles/gganimate.html)
- **gganimate** reference documentation: [`transition_states()`](https://gganimate.com/reference/transition_states.html)
- **gganimate** reference documentation: [`transition_reveal()`](https://gganimate.com/reference/transition_reveal.html)