rggplot2plotlylegend

plotly drops grouped legend (by color, by symbol) when converted from ggplot

I don't quite understand why the legend disappeared when I converted a plot made by ggplot to plotly using ggplotly. The plotly help page did not have any information. I don't think their examples even worked properly on that page. Any help is greatly appreciated!

Sample data

library(scales)
packageVersion("ggplot2")
#> [1] '3.4.0'
library(plotly)
packageVersion("plotly")
#> [1] '4.10.1'

data <- data.frame(
  stringsAsFactors = FALSE,
  Level = c("Fast","Fast","Fast","Fast",
            "Fast","Fast","Slow","Slow","Slow",
            "Slow","Slow","Slow"),
  Period = c("1Year","3Month","1Year","3Month",
             "1Year","3Month","1Year","3Month",
             "1Year","3Month","1Year","3Month"),
  X = c(0.002,0.002,0.1,0.1,0.9,0.9,
        0.002,0.002,0.1,0.1,0.9,0.9),
  Y = c(1.38,1.29,1.61,1.61,1.74,0.98,
        1.14,0.97,1.09,1.1,0.94,0.58)
)

ggplot2

plt <- ggplot(data = data,
             aes(x = X,
                 y = Y,
                 shape = Period,
                 color = Level)) +
  geom_point(alpha = 0.6, size = 3) +
  labs(x = " ",
       y = "Value") +
  scale_y_continuous(labels = number_format(accuracy = 0.1)) +
  guides(color = guide_legend(title = "Level", order = 1),
         shape = guide_legend(title = "Period", order = 2)) +
  theme(axis.text.x = element_text(angle = 90))
plt

Convert to plotly, legend disappeared

ggplotly(plt, height = 500) %>%
  layout(xaxis = list(autorange = "reversed"))

Edit

There was an issue with guides(). If I removed it, the legend in ggplotly showed up

plt2 <- ggplot(data = data,
             aes(x = X,
                 y = Y,
                 shape = Period,
                 color = Level)) +
  geom_point(alpha = 0.6, size = 3) +
  labs(x = " ",
       y = "Value") +
  scale_y_continuous(labels = number_format(accuracy = 0.1)) +
  theme(axis.text.x = element_text(angle = 90))
plt2

ggplotly(plt2, height = 500) %>%
  layout(
    xaxis = list(autorange = "reversed"),
    legend = list(
      title = list(text = '(Period, Level)'))
  )

Solution

  • After OPs Edit:

    Here is a workaround using basic R {plotly} to modify the legend according to @Tung's requirements:

    result

    library(scales)
library(ggplot2)
library(plotly)
library(data.table)

DT <- data.frame(
  stringsAsFactors = FALSE,
  Level = c("Fast","Fast","Fast","Fast",
            "Fast","Fast","Slow","Slow","Slow",
            "Slow","Slow","Slow"),
  Period = c("1Year","3Month","1Year","3Month",
             "1Year","3Month","1Year","3Month",
             "1Year","3Month","1Year","3Month"),
  X = c(0.002,0.002,0.1,0.1,0.9,0.9,
        0.002,0.002,0.1,0.1,0.9,0.9),
  Y = c(1.38,1.29,1.61,1.61,1.74,0.98,
        1.14,0.97,1.09,1.1,0.94,0.58)
)

setDT(DT)

LevelDT <- unique(DT, by = "Level")
PeriodDT <- unique(DT, by = "Period")
LevelDT[, Y := min(DT$Y)-1]
PeriodDT[, Y := min(DT$Y)-1]

plt2 <- ggplot(data = DT,
               aes(x = X,
                   y = Y,
                   shape = Period,
                   color = Level)) +
  geom_point(alpha = 0.6, size = 3) +
  labs(x = " ",
       y = "Value") +
  scale_y_continuous(labels = number_format(accuracy = 0.1)) +
  theme(axis.text.x = element_text(angle = 90))
plt2

markercolors <- hue_pal()(2)

ggplotly(plt2, height = 500) |>
  layout(
    xaxis = list(autorange = "reversed"),
    legend = list(
      title = list(text = ''),
      itemclick = FALSE,
      itemdoubleclick = FALSE,
      groupclick = FALSE
    )
  ) |>
  add_trace(
    data = LevelDT,
    x = ~ X,
    y = ~ Y,
    inherit = FALSE,
    type = "scatter",
    mode = "markers",
    marker = list(
      color = markercolors,
      size = 14,
      opacity = 0.6,
      symbol = "circle"
    ),
    name = ~ Level,
    legendgroup = "Level",
    legendgrouptitle = list(text = "Level")
  ) |>
  add_trace(
    data = PeriodDT,
    x = ~ X,
    y = ~ Y,
    inherit = FALSE,
    type = "scatter",
    mode = "markers",
    marker = list(
      color = "darkgrey",
      size = 14,
      opacity = 0.6,
      symbol = c("circle", "triangle-up")
    ),
    name = ~Period,
    legendgroup = "Period",
    legendgrouptitle = list(text = "Period")
  ) |> style(showlegend = FALSE, traces = 1:4)

    PS: Here the related plotly.js GitHub issue can be found.

    Original answer:

    I'm not sure why they are set to FALSE in the first place, but setting showlegend = TRUE in layout() and style() (for the traces) brings back the legend:

    library(scales)
library(ggplot2)
library(plotly)

data <- data.frame(
  stringsAsFactors = FALSE,
  Level = c("Fast","Fast","Fast","Fast",
            "Fast","Fast","Slow","Slow","Slow",
            "Slow","Slow","Slow"),
  Period = c("1Year","3Month","1Year","3Month",
             "1Year","3Month","1Year","3Month",
             "1Year","3Month","1Year","3Month"),
  X = c(0.002,0.002,0.1,0.1,0.9,0.9,
        0.002,0.002,0.1,0.1,0.9,0.9),
  Y = c(1.38,1.29,1.61,1.61,1.74,0.98,
        1.14,0.97,1.09,1.1,0.94,0.58)
)

# ggplot2
plt <- ggplot(data = data,
              aes(x = X,
                  y = Y,
                  shape = Period,
                  color = Level)) +
  geom_point(alpha = 0.6, size = 3) +
  labs(x = " ",
       y = "Value") +
  scale_y_continuous(labels = number_format(accuracy = 0.1)) +
  guides(color = guide_legend(title = "Period", order = 1),
         shape = guide_legend(title = "", order = 2)) +
  theme(axis.text.x = element_text(angle = 90))
plt

# Convert to plotly, legend disappeared
fig <- ggplotly(plt, height = 500) %>%
  layout(showlegend = TRUE, xaxis = list(autorange = "reversed")) %>%
  style(showlegend = TRUE)
fig

    result