Set guide order for col aesthetics

Helper function to preserve the display order of legends associated with multiple col aesthetics.

Usage

guide_z_order(z, default_aes = "fill")

Arguments

z

A character vector of aesthetic names whose legend order should be preserved.

default_aes

A character scalar giving the primary ggplot2 aesthetic whose legend should appear first. Defaults to "fill".

Value

A guides object that can be added to a ggplot.

Details

This function is primarily intended for use with ggmultiglyph scales such as scale_z_continuous(). Internally, ggplot2 may not preserve the order of aesthetics supplied to a scale when guides are assembled during plot construction (via the internal guide setup machinery i.e. ggplot2:::Guides$setup() in ggplot2 v 4.0.0). As a result, legends corresponding to z aesthetics can appear in an order that differs from the order specified by the user.

guide_z_order() constructs a guides() specification that explicitly assigns guide orders, ensuring that the default ggplot2 aesthetic legend (FOr example, "fill") is displayed first, followed by the supplied z aesthetics in the order given.

See also

guides, guide_legend

Examples

zs <- c("hp", "drat", "wt", "qsec", "vs", "am", "gear", "carb")
mtcars[ , zs] <- lapply(mtcars[ , zs], scales::rescale)

mtcars$cyl <- as.factor(mtcars$cyl)
mtcars$lab <- row.names(mtcars)

library(ggplot2)
theme_set(theme_bw())
options(ggplot2.discrete.colour = RColorBrewer::brewer.pal(8, "Dark2"))
options(ggplot2.discrete.fill = RColorBrewer::brewer.pal(8, "Dark2"))


# Theme for proper display of all the guides
guide_theme <-
  theme(legend.direction = "vertical",
        legend.box = "horizontal",
        legend.position = "bottom",
        legend.text = element_text(margin = margin(l = 7)),
        legend.key.height = unit(1.5, 'lines'))


# Order of guides is scrambled
ggplot(data = mtcars) +
  geom_starglyph(aes(x = mpg, y = disp, fill = cyl),
                 cols = zs, whisker = TRUE, contour = TRUE,
                 size = 5, alpha = 0.8) +
  ylim(c(-0, 550)) +
  scale_z_continuous(z = zs) +
  theme_bw(base_size = 7.5) +
  guide_theme



# Fixing the order of guides by individual assignment
ggplot(data = mtcars) +
  geom_starglyph(aes(x = mpg, y = disp, fill = cyl),
                 cols = zs, whisker = TRUE, contour = TRUE,
                 size = 5, alpha =  0.8) +
  ylim(c(-0, 550)) +
  scale_z_continuous(z = zs) +
  theme_bw(base_size = 7.5) +
  guides(fill = guide_legend(order = 1),
         hp = guide_legend(order = 2),
         drat = guide_legend(order = 3),
         wt = guide_legend(order = 4),
         qsec = guide_legend(order = 5),
         vs = guide_legend(order = 6),
         am = guide_legend(order = 7),
         gear = guide_legend(order = 8),
         carb = guide_legend(order = 9)) +
  guide_theme


# Work-around using guide_z_order
ggplot(data = mtcars) +
  geom_starglyph(aes(x = mpg, y = disp, fill = cyl),
                 cols = zs, whisker = TRUE, contour = TRUE,
                 size = 5, alpha = 0.8) +
  ylim(c(-0, 550)) +
  scale_z_continuous(z = zs) +
  guide_z_order(z = zs, default_aes = "fill") +
  theme_bw(base_size = 7.5) +
  guide_theme