Rectangle theme element with alpha support

This function extends ggplot2::element_rect() to support transparency via an alpha parameter. It maintains full backward compatibility with the original element_rect() function while enabling transparent panel styling, which is particularly useful for foreground panels in 3D plots.

Usage

element_rect(
  fill = NULL,
  colour = NULL,
  linewidth = NULL,
  linetype = NULL,
  color = NULL,
  inherit.blank = FALSE,
  size = lifecycle::deprecated(),
  alpha = NULL
)

Arguments

fill

Fill color for the rectangle. Use NA for no fill.

colour, color

Line color for the rectangle border. Use NA for no border.

linewidth

Line width for the rectangle border.

linetype

Line type for the rectangle border (e.g., "solid", "dashed").

inherit.blank

Should this element inherit from element_blank?

size

Use linewidth instead.

alpha

Transparency level for the rectangle fill, ranging from 0 (completely transparent) to 1 (completely opaque). Particularly useful for styling foreground panels in 3D plots to create layered visual effects.

Value

A theme element object that can be used in theme() specifications.

See also

element_rect for the original function, coord_3d for 3D coordinate systems that utilize foreground panels

Examples

# Basic 3D plot with semi-transparent foreground panels
ggplot(mountain, aes(x, y, z)) +
  stat_surface_3d(fill = "darkblue", color = "lightblue", linewidth = .1) +
  coord_3d(panels = c("background", "ymin")) +
  theme(panel.foreground = element_rect(alpha = 0.6))


# Completely transparent foreground panels
ggplot(mtcars, aes(mpg, wt, qsec)) +
  geom_point() +
  coord_3d(panels = "all") +
  theme(panel.border = element_rect(color = "black"),
        panel.foreground = element_rect(fill = "blue", alpha = 0))