RGraphSpace (version 1.1.1)

make_gspace_legend: Create standalone legends for RGraphSpace's ggplot objects

Description

This accessor builds a standalone legend from a named vector of colors. The resulting legend is returned as a 'grob' object that can be used to add external legends to existing ggplots.

Usage

make_gspace_legend(
  color_palette,
  breaks = NULL,
  legend_title = "Title",
  legend_shape = 21,
  legend_size = 6,
  text_size = 10,
  orientation = c("vertical", "horizontal"),
  justification = c("left", "right"),
  custom_theme = theme()
)
add_gspace_legend(
  plot,
  legend,
  spacer = unit(2, "mm"),
  position = c("right", "top", "bottom", "left")
)

Value

The `make_gspace_legend()` function returns a standalone legend, while the `add_gspace_legend()` function returns a patchwork object containing a plot combined with the generated legend in the specified position.

Arguments

color_palette

A named character vector of colors. Names become legend labels. Values must be valid R color specifications, e.g. `color_palette = c(A = "#FF0000", B = "blue")`.

breaks

A vector indicating numeric breaks for a continuous legend. If missing, `color_palette` will instead produce a discrete legend.

legend_title

The legend title.

legend_shape

Point shape (default 21, for circle).

legend_size

Size of legend points (default 6 mm).

text_size

Text size (default 10 mm).

orientation

Legend arrangement ("vertical" or "horizontal").

justification

Legend justification within bounding box ("left" or "right").

custom_theme

An optional `ggplot2` theme object applied to the legend panel. This allows customizing the appearance of the legend without affecting the main plot.

plot

A GraphSpace plot.

legend

A list with multiple `gspace` legends.

spacer

A grid::unit() value specifying space inserted between merged legends.

position

Placement of legend relative to the main plot.

Details

The object returned by `add_gspace_legend()` behaves like a ggplot for saving, combining with patchwork, arranging in grids, and rendering in standard graphics devices. Internally, however, the original ggplot is converted into a static 'grob' embedded inside a blank ggplot. As a result, the returned object cannot accept new layers, scales, or other ggplot modifications; it is no longer an editable ggplot, but a wrapped graphical representation of the composed figure.

Examples

library(ggplot2)
library(patchwork)

p <- ggplot(mtcars, aes(wt, mpg)) + geom_point()

# Add a discrete standalone legend to a plot
leg1 <- make_gspace_legend(c(A="red", B="blue"), legend_size = 5)
p + leg1 + plot_layout(widths = c(1, 0.1))

# Add a continuous standalone legend to a plot
leg2 <- make_gspace_legend(c("blue", "white","red"), breaks = c(0, 1, 2))
p + leg2 + plot_layout(widths = c(1, 0.1))

# Add a legend list to a plot
legs <- list(leg1, leg2)
add_gspace_legend(plot = p, legs, position = "right")