FR: add a root_color option for treemap traces

When using a colorscale on a treemap trace (without providing a root) the container is shown in black:

library(plotly)

labels = c("A1", "A2", "A3", "A4", "A5", "B1", "B2")
parents = c("", "A1", "A2", "A3", "A4", "", "B1")
values = c("11", "12", "13", "14", "15", "20", "30")

fig <- plot_ly(
  type="treemap",
  labels=labels,
  parents=parents,
  values=values,
  marker=list(colorscale='Reds'))

fig

Example taken from here: https://plotly.com/r/treemaps/

I'd like to change it to white.

In the python plotly library there is a root_color argument to do so:

fig.update_traces(root_color="lightgrey")

see: https://plotly.com/python/treemaps/

It would be great to have the same option in R.

Or is there any workaround to achive this?

从使用 labels、parents、values 和 marker colorscale 的 R treemap 示例开始，然后将其行为与 Python 的 update_traces(root_color="lightgrey") 示例进行比较。当 R treemap API 接受等效的 root 颜色选项，并在未提供 root 的情况下更改容器的颜色时，这项工作就完成了。