Plotly (R) - Pie chart: How to fixate the color assignment color per group?

Question

We are building a Shiny app in which we use a dynamic plotly pie chart. Users can select variables to include in the plot.

Adding custom color codes allow me to add our custom colors, but they won't stick to the grouping variable as they do in plotly bar charts (using the colors command).

Example:

library(plotly)

dat <- data.frame(dis = c(1,2,3), value = c(20,30,24))

plot_ly(dat, labels = ~dis, values = ~value, sort = F, 
        marker = list(colors = c("1" = "#B76C9E", 
                                 "2" = "#4285F4",
                                 "3" = "#EA4335"))) %>%
  add_pie(hole = 0.3) %>%
  layout(legend = list(orientation = 'h'), margin = list(l = 0 , r = 0, t = 0, b = 100, pad = 1),
         yaxis = list(showgrid = FALSE, zeroline = FALSE, showticklabels = FALSE))

But when I remove dis == 1 from the data.frame (like my users will do in the Shiny app) the colors shift and won't remain their assigned color:

dat2 <- data.frame(dis = c(2,3), value = c(30,24))

plot_ly(dat2, labels = ~dis, values = ~value, sort = F, 
        marker = list(colors = c("1" = "#B76C9E", 
                                 "2" = "#4285F4",
                                 "3" = "#EA4335"))) %>%
  add_pie(hole = 0.3) %>%
  layout(legend = list(orientation = 'h'), margin = list(l = 0 , r = 0, t = 0, b = 100, pad = 1),
         yaxis = list(showgrid = FALSE, zeroline = FALSE, showticklabels = FALSE))

Is there a way to lock the color to the categorical variable so "2" will always get the same color?

Removing "1" = "#B76C9E" in the second part of the code fixes the problem, so I guess that you should make this list reactive in your app. It would be easier to help you with an example of the app — bretauv

StupidWolf StupidWolf · Accepted Answer · 2020-05-26T12:59:40

I guess you got to pass update the colors inside the call, something like this.. but I think it's pretty rough:

pal = c("#B76C9E", "#4285F4","#EA4335")
names(pal) = as.character(1:3)

updated_pal = pal[unique(as.character(dat2$dis))]

plot_ly(dat2, 
labels = ~dis, values = ~value, sort = F,
marker=list(colors=updated_pal)) %>%
  add_pie(hole = 0.3) %>%
  layout(legend = list(orientation = 'h'), margin = list(l = 0 , r = 0, t = 0, b = 100, pad = 1),
         yaxis = list(showgrid = FALSE, zeroline = FALSE, showticklabels = FALSE))

Plotly (R) - Pie chart: How to fixate the color assignment color per group?

1 Answers