`transition_layers` and `enter_fade` not working together about gganimate

[thomasp85]

This has been fixed in the dev version of tweenr

[linzi-sg]

I took a look at this. The error was triggered when animating the geom_point layer, because GeomPoint's default_aes for fill is NA (i.e. a logical constant), while part of the transformation done by enter_fade (see gganimate:::transmute_fade for details) involves applying alpha() on various other aesthetic mappings. In particular, the following code

x$fill[no_alpha] <- alpha(x$fill[no_alpha], alpha)

will convert a column of NAs to NA_character_s, which leads to the error when vec_rbind() tries to combine a dataframe of original points (where the fill column is logical) with a dataframe of tweened points (where the fill column has become character).

Workaround

Changing geom_point() to geom_point(fill = NA_character_) in the example would mitigate the issue here. In the long run, though, it may be worthwhile to include some check on the input & output column classes within gganimate:::transmute_fade.

[tnguyenqh]

I had the same error today and i have tried the suggested solution and I had another error: Error in transform_path(data[0, ], data, ease, enter_length, NULL, enter, : The transformr package is required to tween paths and lines

[thomasp85]

@tnguyenqh as the message indicates you need to install the transformr package