Fix bug: ggplotly() no longer removes legends

[trekonom]

This PR proposes a fix for a bug introduced with #2067 and thereby closes #2212.

Specifically #2067 added the line

plotly.R/R/layers2traces.R

Line 105 in 7fb95ed

aes_no_guide <- names(vapply(p$guides, identical, logical(1), "none"))

to take care of guides(aes = "none"). However, this has the unwanted effect to remove legends for all aesthetics mentioned in guides() as can be seen from the following reprex which should show a color legend:

library(ggplot2)
library(plotly, warn=FALSE)

p <- ggplot(mtcars, aes(hp, mpg, color = factor(cyl))) +
  geom_point() +
  guides(color = guide_legend())

aes_no_guide <- names(vapply(p$guides, identical, logical(1), "none"))

aes_no_guide
#> [1] "colour"

ggplotly()

The PR fixes that by including only those aes for which vapply(p$guides, identical, logical(1), "none")) is TRUE:

aes_no_guide <- names(p$guides)[vapply(p$guides, identical, logical(1), "none")]

aes_no_guide
#> character(0)

^{Created on 2023-02-09 with reprex v2.0.2}

[cpsievert]

Awesome, thank you!

[simonsteiger]

While working with guides() and ggplotly(), I realised that the legend for those arguments specified in guides() disappears.

This seems to be despite @trekonom's fix above.

Running on
plotly 4.10.1.9000
ggplot2 3.4.1

library(plotly)
library(ggplot2)

df <- data.frame(x = rnorm(10), y = rnorm(10), group = rep(c("A", "B"), times = 5))

# Plot without guides
p1 <- ggplot(df, aes(x = x, y = y, color = group)) +
  geom_line()

# Plot with guides
p2 <- ggplot(df, aes(x = x, y = y, color = group)) +
  geom_line() +
  guides(color = guide_legend())

# Convert with guides
ggplotly(p1)
# Legend shown

# Convert without guides
ggplotly(p2)
# Legend not shown

[trekonom]

Unfortunately I could not reproduce your issue (Could you check your code after re-installing the plotly dev version?).

Running your code with the dev version gives me a legend for both cases:

library(plotly, warn=FALSE)
#> Loading required package: ggplot2

set.seed(123)

df <- data.frame(x = rnorm(10), y = rnorm(10), group = rep(c("A", "B"), times = 5))

# Plot without guides
p1 <- ggplot(df, aes(x = x, y = y, color = group)) +
  geom_line()

# Plot with guides
p2 <- ggplot(df, aes(x = x, y = y, color = group)) +
  geom_line() +
  guides(color = guide_legend())

# Convert with guides
ggplotly(p1)

# Legend shown

# Convert without guides
ggplotly(p2)

# Legend not shown

^{Created on 2023-03-05 with reprex v2.0.2}

[simonsteiger]

Thank you for your comment and apologies – you are correct, the legend is shown.

I initially discovered the "missing legend" issue when I reversed the legend order with guide_legend(reverse = TRUE) and then used ggplotly().
With your fix, I've now tried to reverse the legend order with guide_legend(reverse = TRUE), but the legend remains in the original order for the plotly plot. The ggplot version is reversed.

Since this is not related to missing legends anymore, I will open a new issue on reversing the legend.

library(plotly, warn=FALSE)
#> Loading required package: ggplot2

set.seed(123)

df <- data.frame(x = rnorm(10), y = rnorm(10), group = rep(c("A", "B"), times = 5))

p1 <- ggplot(df, aes(x = x, y = y, color = group)) +
  geom_line() +
  guides(color = guide_legend())
# Legend order default

# Plot with guides
p2 <- ggplot(df, aes(x = x, y = y, color = group)) +
  geom_line() +
  guides(color = guide_legend(reverse = TRUE))
# Legend order reversed

# Convert ggplot with reversed legend order
ggplotly(p2)
# Legend not reversed