Bug: patterns in legend keys

[teunbrand]

When providing a plain pattern as a fixed 'fill' aesthetic, the fill is not transferred to the legend key fill.

library(scales)
library(ggplot2)
packageVersion("ggplot2")
#> [1] '3.4.4.9000'

grad <- grid::linearGradient(pal_viridis()(10))

p <- ggplot(mpg, aes(factor(cyl), colour = "fixed"))

p + geom_bar(fill = grad)

If we instead provide the pattern as a list, it works fine.

p + geom_bar(fill = list(grad))

^{Created on 2023-12-18 with reprex v2.0.2}

The culprit seems to be the following line:

ggplot2/R/guide-legend.R

Line 233 in a4be39d

layer_params <- layer$aes_params[n == 1]

Where only params of length 1 are included in the legend. Since a pattern is a list, it does not have length 1.

[teunbrand]

Considered fixed by #5595.