Ribbon and area charts with pattern overlays

Drop-in replacements for ggplot2::geom_ribbon() and ggplot2::geom_area() that add a pattern aesthetic. Patterns are clipped to the ribbon polygon using the same device-independent in-R geometry as geom_polygon_pattern().

Usage

geom_ribbon_pattern(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  ...,
  outline.type = "both",
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

geom_area_pattern(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "stack",
  ...,
  outline.type = "upper",
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

mapping

Aesthetic mappings created by ggplot2::aes().

data

Data frame.

stat

Statistical transformation. Default "identity".

position

Position adjustment. Default "identity" for geom_ribbon_pattern(), "stack" for geom_area_pattern().

...

Other arguments passed to the layer.

outline.type

Which sides of the ribbon to draw. One of "both" (default), "upper", "lower", or "full".

na.rm

If FALSE (default), missing values are removed with a warning.

show.legend

Logical. Should this layer be included in the legend?

inherit.aes

If FALSE, overrides the default aesthetics.

Value

A ggplot2 layer.

Pattern aesthetics

In addition to all aesthetics accepted by ggplot2::geom_ribbon(), these geoms accept:

pattern

Character name of the pattern. One of "none", "hatch", "crosshatch", "horizontal", "vertical", "dots", "weave", or a custom pattern registered with register_pattern(). Each base pattern (except "none") also has _dense and _sparse variants (e.g. "hatch_dense", "dots_sparse") for pre-set tighter or looser spacing.

pattern_colour

Colour of pattern lines/dots. Default "black".

pattern_linewidth

Line width for line-based patterns. Default 1.

pattern_spacing

Spacing between pattern elements in millimetres. Default 5. Smaller values produce denser patterns; larger values produce sparser patterns. Named density variants (e.g. "hatch_dense") bake in a pre-set spacing multiplier but still respect explicit pattern_spacing values.

pattern_angle

Angle in degrees for hatch patterns. Default 45.

pattern_size

Dot radius in millimetres for the "dots" pattern. Default 0.5.

Limitations

orientation = "y" (horizontal ribbons/areas) is not supported for the pattern overlay. The base ribbon renders correctly, but the pattern is silently skipped.

NA gaps in the ribbon data collapse into the surrounding polygon rather than producing separate pattern segments.

Examples

library(ggplot2)

# Confidence band around a sine wave
x <- seq(0, 2 * pi, length.out = 60)
df <- data.frame(x = x, ymin = sin(x) - 0.3, ymax = sin(x) + 0.3)
ggplot(df, aes(x, ymin = ymin, ymax = ymax)) +
  geom_ribbon_pattern(pattern = "hatch", fill = "lightblue") +
  theme_minimal()


# Stacked area chart with patterns
df2 <- data.frame(
  x       = c(1:5, 1:5),
  y       = c(1, 2, 3, 2, 1, 2, 1, 3, 2, 1),
  group   = rep(c("A", "B"), each = 5),
  pattern = rep(c("hatch", "crosshatch"), each = 5)
)
ggplot(df2, aes(x, y, fill = group, pattern = pattern)) +
  geom_area_pattern(position = "stack") +
  scale_pattern_identity(guide = "legend") +
  theme_minimal()