Patterns ‘circle’, ‘pch’, ‘regular_polygon’, ‘rose’

Introduction to the ‘circle’, ‘pch’, ‘regular_polygon’, and ‘rose’ patterns

The ‘circle’ pattern draws circles
The ‘pch’ pattern draws “plotting character” symbols as in graphics::points()
The ‘regular_polygon’ pattern draws convex/star regular polygons
The ‘rose’ pattern draws rose curves
For more info on these patterns see their {gridpattern} documentation:

Pattern Parameters

aesthetic	description	default	possible values
pattern_colour	Stroke colour	‘grey20’	colour
pattern_fill	Fill colour	‘grey80’	colour
pattern_angle	Rotation angle	30	angle in degrees
pattern_density	Approx. fraction of area the pattern fills	0.2	value in range [0, 1] (fraction)
pattern_spacing	Spacing between repetitions of pattern	0.05	value in `pattern_units` grid units
pattern_xoffset	Shift pattern along x axis	0	value in `pattern_units` grid units
pattern_yoffset	Shift pattern along y axis	0	value in `pattern_units` grid units
pattern_units	Pattern grid unit	‘snpc’	`grid::unit()` unit i.e. ‘snpc’, ‘cm’, and ‘inches’
pattern_alpha	Alpha	NA	value in range [0, 1] or NA
pattern_linetype	Stroke linetype	1	linetype
pattern_size	Stroke linewidth	1	linewidth
pattern_type	Pattern type	NA	See circle, pch, regular_polygon, and rose pattern documentation
pattern_subtype	Pattern subtype	NA	See circle, pch, regular_polygon, and rose pattern documentation
pattern_grid	Grid type	‘square’	‘square’, ‘hex’, or ‘hex_circle’
pattern_rot	Pattern symbol rotation angle	0	angle in degrees
pattern_shape	Pattern shape	NA	See pch and regular_polygon
pattern_frequency	Frequency	0.1	Angular frequency in ‘rose’ pattern

There are also a number of parameters for extra control of legend sizing and aspect ratio adjustments. See the ‘Pattern Parameters - Common’ for more information.

Data

Standard data for all the example plots

df <- data.frame(trt = c("a", "b", "c"), outcome = c(2.3, 1.9, 3.2))
df
#>   trt outcome
#> 1   a     2.3
#> 2   b     1.9
#> 3   c     3.2

Vanilla ggplot2

ggplot(df, aes(trt, outcome)) +
  geom_col(aes(fill=trt),colour='black') +
  theme_bw() +
  labs(title = "Plain ggplot2")

Use the `{ggpattern}` geom

Use ggpattern::geom_col_pattern() instead of ggplot2::geom_col().
Set pattern = 'circle'
Default legends in ggplot2 are usually too small to show off an example of the pattern, so it will usually be necessary to increase the key size.

ggplot(df, aes(trt, outcome)) +
  geom_col_pattern(aes(fill=trt),colour='black', pattern = 'circle') +
  theme_bw() +
  labs(title = "ggpattern") +
  theme(legend.key.size = unit(1.5, 'cm'))

The Density Aesthetic (‘pch’ example)

The aesthetic pattern_density roughly corresponds to the fraction of the filled area which should be covered by the pattern.

In the following plot the density of striping is increased to 50% of the fill area.

ggplot(df, aes(trt, outcome)) +
  geom_col_pattern(
    aes(fill=trt, pattern_shape=trt),
    colour          = 'black', 
    pattern         = 'pch',
    pattern_density = 0.5
  ) +
  theme_bw() +
  labs(title = "Fixed density of 0.5 (50% of the fill area)") + 
  theme(legend.key.size = unit(1.5, 'cm'))

The Density Aesthetic as a Mapped Aesthetic

ggplot(df, aes(trt, outcome)) +
  geom_col_pattern(
    aes(fill = trt, pattern_density = trt),
    colour          = 'black', 
    pattern         = 'circle'
  ) +
  theme_bw() +
  labs(title = "Aesthetic Mapping of 'trt' to Density") + 
  theme(legend.key.size = unit(1.5, 'cm'))

The Density Aesthetic as a Mapped Aesthetic with Manual Scale

scale_pattern_density_manual() can be used to manually control how the variable is mapped to the density.

ggplot(df, aes(trt, outcome)) +
  geom_col_pattern(
    aes(fill = trt, pattern_density = trt),
    colour          = 'black', 
    pattern         = 'regular_polygon',
    pattern_shape   = 'convex6',
    pattern_fill    = 'white',
    pattern_colour  = NA,
    pattern_grid    = 'hex'
  ) +
  theme_bw() +
  labs(title = "Aesthetic Mapping of 'trt' to Density") + 
  theme(legend.key.size = unit(1.5, 'cm')) + 
  scale_pattern_density_manual(values = c(a = 0.7, b=0.8, c=0.9))

The Spacing Aesthetic as a Mapped Aesthetic

ggplot(df, aes(trt, outcome)) +
  geom_col_pattern(
    aes(fill = trt, pattern_spacing = trt, pattern_shape = trt),
    pattern_density = 0.7,
    colour          = 'black', 
    pattern         = 'regular_polygon',
    pattern_scale   = 0.2
  ) +
  theme_bw() +
  labs(title = "Aesthetic Mapping of 'trt' to Spacing") + 
  scale_pattern_shape_manual(values = c(a = "circle", b = "convex3", c = "star5")) +
  theme(legend.key.size = unit(1.5, 'cm'))

The Fill Aesthetic as a Mapped Aesthetic (‘rose’ example)

ggplot(df, aes(trt, outcome)) +
  geom_col_pattern(
    aes(fill = trt, pattern_fill = trt),
    colour          = 'black', 
    pattern         = 'rose',
    pattern_frequency = 5/2,
    pattern_density = 0.7,
    pattern_spacing = 0.15
  ) +
  theme_bw() +
  labs(title = "Aesthetic Mapping of 'trt' to Pattern Fill") + 
  scale_pattern_fill_viridis_d() + 
  theme(legend.key.size = unit(1.5, 'cm'))

Patterns ‘circle’, ‘pch’, ‘regular_polygon’, ‘rose’ - Parameters and Examples