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Source: vignettes/colors.qmd

Colors

The class_color object has some useful utilities for working with colors. It mostly makes use of functions from the tinter and farver packages.

The class_color object takes R color names or hex strings as input.

my_color <- class_color("orchid")

The underlying data of class_color can be retrieved with the c function or via the @color property:

c(my_color)
#> [1] "#DA70D6FF"
my_color@color
#> [1] "#DA70D6FF"

The ob_* classes have fill and color properties that can take direct character strings or class_color objects as input.

ggdiagram() +
  ob_circle(fill = my_color)

A variety of color manipulation functions are available. Colors can be darkened:

ggdiagram() +
  ob_circle(fill = my_color@darken(.5))

Colors can be lightened:

ggdiagram() +
  ob_circle(fill = my_color@lighten(.5))

Colors can be made transparent:

ggdiagram() +
  ob_circle(fill = my_color@transparentize(.5)) +
  ob_circle(fill = my_color@transparentize(.5), center = ob_point(1,0))

Here we create sequences of shades with the @lighten and @darken properties:

ggdiagram() + 
  {my_array <- ob_circle(color = NA) %>% 
    ob_array(fill = my_color@lighten(seq(.1,1,length.out = 5)), 
             k = 5, 
             sep = .2)} + 
  ob_circle(color = NA) %>% 
    ob_array(fill = my_color@darken(seq(0,.9,length.out = 5)), 
             k = 5, 
             sep = .2) %>% 
    place(my_array, "below", sep = .2)

The @lighten function makes colors appear the same as @transparentize with a white background. This feature can make be useful when text labels need to be placed over transparent shapes. The @darken function makes colors appear the same as @transparentize with a black background (with @darken’s amount values subtracted from 1).

Color Properties

Different properties of colors and be retrieved and set. Using the HSV color model for Hue (0–360), Saturation (0–1), and Value/Brightness (0–1)

my_color@hue
#> [1] 302.2642
my_color@saturation
#> [1] 0.4862385
my_color@brightness
#> [1] 0.854902

We can set a sequence of colors with the same brightness and saturation as the original color but with different hues:

my_color_array <- class_color(my_color, hue = my_color@hue + seq(0,720, length.out = 12))

ggdiagram() +
  ob_circle(color = NA) %>%
  ob_array(fill = my_color_array,
           k = 12,
           sep = .2)

We can set an array of colors with the same hue as the original color but with different saturation and/or brightness:

my_color_array <- class_color(my_color, saturation = seq(.1,.6,.1))

ggdiagram() +
  ob_circle(color = NA) %>%
  ob_array(fill = my_color_array,
           k = 6,
           sep = .2)

Alternately, the RGB (Red/Green/Blue) color properties can also be retrieved or set. Values are integers ranging from 0 to 255.

my_color@red
#> [1] 218
my_color@green
#> [1] 112
my_color@blue
#> [1] 214