This shadow lets you show the raw data behind the current frame. Both past and/or future raw data can be shown and styled as you want.

shadow_mark(past = TRUE, future = FALSE, ..., exclude_layer = NULL)

## Arguments

past Should raw data from earlier in the animation be shown Should raw data from later in the animation be shown changes to the shadow data, e.g. alpha = alpha/2 or colour = 'grey' Indexes of layers that should be excluded.

Other shadows: shadow_null, shadow_trail, shadow_wake

## Examples

# Use any of the aesthetics to add a style to either the past or the future raw data.
# Adding a grouping variable in a transition call prior to calling shadow_mark() will
# allow transitioning through different states in time.

p1 <- ggplot(airquality, aes(Day, Temp)) +
geom_line(color = 'red', size = 1) +
transition_time(Month) +
shadow_mark(colour = 'black', size = 0.75)

# animate(p1)

# Add a future = TRUE argument to show data later in the animation.

p2 <- ggplot(airquality, aes(Day, Temp)) +
geom_line(color = 'red', size = 1) +
transition_time(Month) +
shadow_mark(color = 'black', size = 0.75, past = FALSE, future = TRUE)

# animate(p2)