Bug: ggplotly ignores colours in ggplot2::scale_fill_gradientn when limits are below the range of the data

This is an odd bug (reported first as a heatmaply issue).

If we create a ggplot2 object with colors based on scale_fill_gradientn, then ggplotly respect the colors. But if the limits are set to be within (instead of outside) the range of the data, then ggplotly stops respecting the colors. This may be some fallback for how to deal with NA colors (but I don't know enough about ggplotly to know for sure).

Here is a self contained example:

library(ggplot2)
library(viridis)
library(plotly)
# Equivalent fill scales do the same job for the fill aesthetic
p <- ggplot(faithfuld, aes(waiting, eruptions)) +
  geom_raster(aes(fill = density)) +
  scale_fill_gradientn(colours = viridis(10), limits = c(0.001,.01))
p
ggplotly(p)

Plot in ggplot2:

Plot in plotly (see the wrong colors produced!)

首先執行使用 ggplot2、viridis 和 plotly 的自包含 R 範例，然後比較當 scale_fill_gradientn 的限制低於資料範圍時 ggplot2 和 ggplotly 的色彩輸出。完成的標準是，在此情況下 ggplotly 保留預期的漸層色彩。