gganimate：如何使堆積條形圖從 x 軸向上平滑增長

Question

我在為堆疊的 static plot 設置動畫時遇到問題。 （見下文 animation）

animation 從左到右以不穩定的方式移動，而不是每個條從 x 軸向上增長。 堆疊的部分也不會很順利地一起生長，我似乎無法解決。

我需要在我的代碼中進行哪些更改，以便隨着動畫 plot 沿 x 軸過渡，各個條形向上增長？ 我還想讓堆疊的條更平滑地增長，所以堆疊的條部分不會“扔”在彼此的頂部。

這怎么可能？

本文頂部的 gif 是我正在尋找的，但我不明白他的代碼與我的代碼有何不同以及在哪里：理想 animation

這是我的代表：

#Static df
library(dplyr)
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union
year <- as.numeric(c(1996:2015,
                       1996:2015,
                       1996:2015))
c <- c(39, 40, 67, 80, 30, 140, 90, 23, 100, 123,
       140, 160, 100, 89, 173, 200, 32, 90, 100, 211,
       1, 2, 1, 13, 3, 3, 30, 1, 3, 3,
       1, 1, 20, 2, 1, 10, 1, 2, 1, 1,
       1, 3, 1, 2, 1, 3, 1, 3, 6, 1,
       1, 30, 1, 1, 8, 9, 1, 32, 1, 1)
cat <- as.character(c("out", "out", "out", "out", "out", "out", "out", "out", "out", "out",
                   "out", "out", "out", "out", "out", "out", "out", "out", "out", "out",
                   "in", "in", "in", "in", "in", "out", "in", "in", "in", "in",
                   "in", "in", "in", "in", "in", "in", "in", "in", "in", "in",
                   "other", "other", "other", "other", "other", "other", "other", "other", "other", "other",
                   "other", "other", "other", "other", "other", "other", "other", "other", "other", "other"))
cat <- as.factor(cat)
static_df_test <- data.frame(year, c, cat) %>%
  select(year, cat, c) %>%
  arrange(year, cat)


#Static plot
library(ggplot2)
(static_plot <- ggplot(static_df_test) +
    geom_bar(data = static_df_test, stat="identity", position ="stack",
             aes(x = year, y = c, fill = cat)) +
    scale_x_continuous(breaks = seq(1996, 2015, 1),
                       expand = c(0.003, 0.003),
                       labels = c(1996, 97, 98, 99, 2000,
                                  "01", "02", "03", "04", "05", "06",
                                  "07", "08", "09", 10, 11, 12, 13, 14, 15)) +
    scale_y_continuous(breaks = seq(0, 250, 25),
                       expand = c(0,0),
                       limits = c(0,250)) +
    labs(x = "year", y = "c")
)

#Animated plot
library(gganimate)
library(ggplot2)
ani <- (static_plot) +
  transition_time(as.integer(year)) +
  enter_grow() + shadow_mark(past = TRUE)

animate(ani, fps = 8, 50, duration = 15,
        width = 1500, height = 750, renderer = gifski_renderer())

現在，條形圖通過從上一個條形向右移動來過渡。 在此處查看當前的 animation：

預先感謝您的任何幫助！

Answer 1

可能有更正確的方法可以做到這一點，但可以通過更改構建初始 static plot 的方式並使用transition_layers()和enter_drift()來完成。

請注意，為了簡化我的示例，我只包括 1996-2000 年。 要為所有年份設置動畫，只需復制並粘貼geom_bar()部分並更改被過濾的年份。

#Static plot
library(ggplot2)
(static_plot <- ggplot(static_df_test) +
    geom_bar(data = static_df_test %>% filter(year == 1996), stat="identity", position ="stack",
             aes(x = year, y = c, fill = cat)) +
    geom_bar(data = static_df_test %>% filter(year == 1997), stat="identity", position ="stack",
             aes(x = year, y = c, fill = cat)) +
    geom_bar(data = static_df_test %>% filter(year == 1998), stat="identity", position ="stack",
             aes(x = year, y = c, fill = cat)) +
    geom_bar(data = static_df_test %>% filter(year == 1999), stat="identity", position ="stack",
             aes(x = year, y = c, fill = cat)) +
    geom_bar(data = static_df_test %>% filter(year == 2000), stat="identity", position ="stack",
             aes(x = year, y = c, fill = cat)) +
    scale_x_continuous(breaks = seq(1996, 2015, 1),
                       expand = c(0.003, 0.003),
                       labels = c(1996, 97, 98, 99, 2000,
                                  "01", "02", "03", "04", "05", "06",
                                  "07", "08", "09", 10, 11, 12, 13, 14, 15)) +
    scale_y_continuous(breaks = seq(0, 250, 25),
                       expand = c(0,0),
                       limits = c(0,250)) +
    labs(x = "year", y = "c")
)

#Animated plot
library(gganimate)
library(ggplot2)

ani <- (static_plot) +
  transition_layers(layer_length = 1, transition_length = 2) +
  enter_drift(x_mod = 0, y_mod = -max(static_df_test$c))

animate(ani, fps = 10, duration = 10,
        width = 600, height = 500, renderer = gifski_renderer())

通過將每個基於年份的條形圖放置在其自己的圖層上，我們可以使用transition_layers()使它們一一出現，同時保留所有舊圖層。 我們使用enter_drift()為每個條設置動畫，就好像它從圖表下方向上漂移一樣。

動畫 output 在這里：鏈接

Answer 2

有一個更簡單的解決方案。 將您的“年份”變量視為一個因素而不是數字。 這將使酒吧像你想要的那樣平穩地向上增長。

基本上為您的 static plot 代碼使用以下塊，它將起作用：

static_plot <- ggplot(static_df_test) +
    geom_bar(data = static_df_test, stat="identity", position ="stack",
             aes(x = as.factor(year), y = c, fill = cat)) +
    scale_y_continuous(breaks = seq(0, 250, 25),
                       expand = c(0,0),
                       limits = c(0,250)) +
    labs(x = "year", y = "c")

我知道我有點晚了，但我希望它有所幫助。