Patterns ‘gradient’, ‘ambient’, ‘plasma’ - Parameters and Examples

suppressPackageStartupMessages({
  library(ggplot2)
  library(ggpattern)
})

Introduction to the ‘gradient’, ‘ambient’, and ‘plasma’ patterns

• The ‘gradient’ pattern fills the geom with color gradients. This pattern either depends on the R package magick or a graphics device and version of R that supports the new R 4.1 gradient feature.

• The ‘plasma’ pattern uses Imagemagick (magick) to generate some fractal noise arrays which are coloured and used to fill the geom. This pattern depends on the R package magick.

• The ambient package offers a way of creating multiple different types of noise as a matrix of values. The ‘ambient’ pattern maps this noise to a colour gradient between two user-specified colours.

• For more info on these patterns see their gridpattern documentation:

  • help("grid.pattern_gradient", package = "gridpattern")
  • help("grid.pattern_plasma", package = "gridpattern")
  • help("grid.pattern_ambient", package = "gridpattern")

Pattern Parameters

aesthetic	description	default
pattern_fill	Noise colour	‘grey80’
pattern_fill2	Second colour (‘ambient’, ‘gradient’)	‘#4169E1’
pattern_scale	Extra scaling	1
pattern_alpha	Alpha	NA
pattern_type	Type of noise (‘ambient’)	‘simplex’
pattern_frequency	Granularity of features in noise	0.1
pattern_aspect_ratio	Override aspect ratio	NA
pattern_key_scale_factor	Additional scale factor for legend	1

Example Data

df <- data.frame(
  trt     = c("a", "b", "c"), 
  outcome = c(2.3, 1.9, 3.2)
)

Example: pattern = 'plasma' - With pattern_alpha

if (require("magick")) {

ggplot(df, aes(trt, outcome)) +
  geom_col_pattern(
    aes(
      fill         = trt,
      pattern_fill = trt
    ),
    fill          = NA,
    pattern       = 'plasma',
    pattern_alpha = 1,
    pattern_scale = 2,
    colour        = 'black'
  ) +
  theme_bw(15) +
  labs(
    title    = "ggpattern::geom_col_pattern()",
    subtitle = "pattern='plasma'"
  ) +
  theme(legend.key.size = unit(1.5, 'cm'))

}
#> Loading required package: magick
#> Linking to ImageMagick 6.9.12.3
#> Enabled features: cairo, fontconfig, freetype, heic, lcms, pango, raw, rsvg, webp
#> Disabled features: fftw, ghostscript, x11

if (require("magick")) {

ggplot(mtcars) +
  geom_density_pattern(
    aes(
      x             = mpg,
      pattern_fill  = as.factor(cyl)
    ),
    pattern      = 'plasma',
    pattern_alpha = 0.7
  ) +
  theme_bw(15) +
  theme(legend.position = 'none') +
  labs(
    title    = "ggpattern::geom_density_pattern()",
    subtitle = "pattern='plasma'"
  )

}

Example: pattern_type = 'gradient' - Fade to white

if (require("magick")) {

ggplot(df, aes(trt, outcome)) +
  geom_col_pattern(
    aes(
      pattern_fill        = trt,
      pattern_orientation = trt
    ), 
    pattern       = 'gradient', 
    pattern_fill2 = 'white', 
    colour        = 'black'
  ) +
  theme_bw(15) +
  labs(
    title    = "ggpattern::geom_col_pattern()",
    subtitle = "pattern = 'gradient'"
  ) +
  theme(
    legend.key.size = unit(1.5, 'cm')
  )

}

Example: pattern_type = 'gradient' - Fade to dark blue

if (require("magick")) {

ggplot(df, aes(trt, outcome)) +
  geom_col_pattern(
    aes(
      pattern_fill        = trt,
      pattern_orientation = trt
    ), 
    pattern       = 'gradient', 
    pattern_fill2 = '#445566', 
    colour        = 'black'
  ) +
  theme_bw(15) +
  labs(
    title    = "ggpattern::geom_col_pattern()",
    subtitle = "pattern = 'gradient'"
  ) +
  theme(
    legend.key.size = unit(1.5, 'cm')
  )

}

Example: pattern_type = 'gradient' - Fade to transparent

if (require("magick")) {

ggplot(df, aes(trt, outcome)) +
  geom_col_pattern(
    aes(
      pattern_fill        = trt,
      pattern_orientation = trt
    ), 
    pattern       = 'gradient', 
    pattern_fill2 = NA, 
    fill          = NA,
    colour        = 'black'
  ) +
  theme_bw(15) +
  labs(
    title    = "ggpattern::geom_col_pattern()",
    subtitle = "pattern = 'gradient'"
  ) +
  theme(legend.key.size = unit(1.5, 'cm'))

}

Example: pattern_type = 'gradient' - Non-rectangular geom

if (require("magick")) {

ggplot(mtcars) +
  geom_density_pattern(
    aes(
      x = mpg, 
      pattern_fill = as.factor(cyl),
      pattern_orientation = as.factor(cyl)
    ), 
    pattern       = 'gradient',
    pattern_fill2 = NA, 
    fill          = NA
  ) +
  theme_bw(15) +
  labs(
    title    = "ggpattern::geom_density_pattern()",
    subtitle = "pattern = 'gradient'"
  ) +
  theme(legend.key.size = unit(1.5, 'cm'))

}

Example: `pattern_type = ‘ambient’

if (require("ambient")) {
ggplot(df, aes(trt, outcome)) +
  geom_col_pattern(
    aes(pattern_fill = trt),
    pattern       = 'ambient', 
    pattern_fill2 = 'white',
    colour        = NA, 
    fill          = NA
  ) +
  theme_bw(15) +
  labs(
    title    = "ggpattern::geom_density_pattern()",
    subtitle = "pattern = 'ambient'"
  ) +
  theme(legend.position = 'none')
}
#> Loading required package: ambient

if (require("ambient")) {
ggplot(mtcars) +
  geom_density_pattern(
    aes(
      x = mpg, 
      pattern_fill  = as.factor(cyl), 
      pattern_fill2 = as.factor(cyl)
    ), 
    pattern = 'ambient'
  ) +
  theme_bw(15) +
  theme(legend.key.size = unit(2, 'cm')) + 
  scale_pattern_fill_brewer (palette = 'Accent', direction =  1) + 
  scale_pattern_fill2_brewer(palette = 'Dark2' , direction =  1) + 
  labs(
    title    = "ggpattern::geom_density_pattern()",
    subtitle = "pattern = 'ambient'"
  ) 
}