Adding traces to plotly animations in R - r

Question

I am trying to develop a Business Cycle Clock similar to https://kosis.kr/visual/bcc/index/index.do?language=eng.
I've already achieved most of the things I wanted to replicate, but I can't figure it out how to add these traces (for example, in the link above set speed to 10 and trace length to 5 and then click on 'Apply' to understand what I mean).
Does anyone have any idea how to implement it? It would make the "clock" much easier to read. Thanks in advance.
Reprocible example:
library(plotly)
library(dplyr)
library(magrittr)
variable <- rep('A',10)
above_trend <- rnorm(10)
mom_increase <- rnorm(10)
ref_date <- seq.Date('2010-01-01' %>% as.Date,
length.out = 10,by='m')
full_clock_db <- cbind.data.frame(variable, above_trend, mom_increase, ref_date)
freq_aux = 'm'
ct = 'Brazil'
main_title = paste0('Business Cycle Clock para: ', ct)
m <- list(l=60, r=170, b=50, t=70, pad=4)
y_max_abs = 2
x_max_abs = 5
fig = plot_ly(
data = full_clock_db,
x = ~mom_increase,
y = ~above_trend,
color = ~variable,
frame = ~ref_date,
text = ~variable,
hoverinfo = "text",
type = 'scatter',
mode = 'markers'
) %>%
animation_opts( frame = 800,
transition = 500,
easing = "circle",
redraw = TRUE,
mode = "immediate") %>%
animation_slider(
currentvalue = list(prefix = "Período", font = list(color="red"))
)
fig

Answer 1

Another more elegant solution would be to rely on ggplot2 + gganimate:
library(ggplot2)
library(gganimate)
ggplot(full_clock_db, aes(x = mom_increase, y = above_trend)) +
geom_point(aes(group = 1L)) +
transition_time(ref_date) +
shadow_wake(wake_length = 0.1, alpha = .6)
You cna play with different shadow_* functions to find the one to your liking.

Answer 2

One way would be to use a line plot and repeat points as necessary. Here's an example as POC:
library(dplyr)
library(plotly)
e <- tibble(x = seq(-3, 3, 0.01)) %>%
mutate(y = dnorm(x)) %>%
mutate(iter = 1:n())
accumulate <- function(data, by, trace_length = 5L) {
data_traf <- data %>%
arrange({{ by }}) %>%
mutate(pos_end = 1:n(),
pos_start = pmax(pos_end - trace_length + 1L, 1L))
data_traf %>%
rowwise() %>%
group_map(~ data_traf %>% slice(seq(.x$pos_start, .x$pos_end, 1L)) %>%
mutate("..{{by}}.new" := .x %>% pull({{by}}))) %>%
bind_rows()
}
enew <- e %>%
accumulate(iter, 100)
plot_ly(x = ~ x, y = ~ y) %>%
add_trace(data = e, type = "scatter", mode = "lines",
line = list(color = "lightgray", width = 10)) %>%
add_trace(data = enew, frame = ~ ..iter.new,
type = "scatter", mode = "lines") %>%
animation_opts(frame = 20, 10)
The idea is that for each step, you keep the trace_length previous steps and assign them to the same frame counter (here ..iter.new). Then you plot lines instead of points and you have a sort of trace..