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Overview

This article will demonstrate more advanced content, including how to:

Use different fonts
Visualise spatial data
Change the stat
Use non-supported aesthetics
Use delayed evaluation
Add contrasting dark or light text on polygons

library(ggblanket)
library(ggplot2)
library(dplyr)
library(stringr)
library(tidyr)
library(palmerpenguins)

1. Use different fonts

The showtext and sysfonts packages support the use of different fonts from Google. The *_mode theme functions provide base_family, title_family, subtitle_family and caption_family arguments. Fonts can be identified on the Google fonts website.

sysfonts::font_add_google("Covered By Your Grace", "grace")
sysfonts::font_add_google('Roboto Slab', 'roboto_slab')
sysfonts::font_add_google('Syne Mono', 'syne')

showtext::showtext_auto(enable = TRUE)

penguins |>
  mutate(across(sex, \(x) str_to_sentence(x))) |>
  gg_point(
    x = flipper_length_mm,
    y = body_mass_g,
    col = sex,
    facet = species,
    title = "palmerpenguins::penguins body mass by flipper length",
    subtitle = "Palmer Archipelago, Antarctica",
    caption = "Source: Gorman, 2020",
    theme = light_mode_rt(
      base_size = 11,
      base_family = "grace", 
      title_family = "roboto_slab", 
      subtitle_family = "syne"),
    )


showtext::showtext_auto(enable = FALSE)

2. Visualise spatial data

As ggblanket wraps the ggplot2::geom_sf and ggplot2::geom_raster functions, spatial vector and array data can be visualised.

sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE) |>
  gg_sf(col = AREA) +
  ggeasy::easy_remove_axes()

stars::read_stars(system.file("tif/L7_ETMs.tif", package = "stars")) |>
 tibble::as_tibble() |>
 gg_raster(
   x = x,
   y = y,
   col = L7_ETMs.tif,
   facet = band,
   col_title = "L7 ETMs",
  ) +
  ggeasy::easy_remove_axes()

3. Change the `stat`

The default stat of each gg_* function can be changed.

penguins |> 
  gg_point(
    stat = "sum",
    x = species,
    y = island,
  ) +
  labs(size = "Count")

penguins |>
  gg_pointrange(
    x = species,
    y = flipper_length_mm, 
    stat = "summary", 
    na.rm = TRUE,
    size = 0.1,
    x_labels = \(x) str_sub(x, 1, 1),
  )

library(ggforce)

ggplot2::economics |>
  slice_head(n = 35) |> 
  gg_path(
    x = date, 
    y = unemploy,
    stat = "bspline",
    n = 100, 
    linewidth = 1,
  )

4. Use non-supported aesthetics

Most functions have the commonly needed aesthetics directly available as an argument. For those that are not available, you can either use mapping argument. The mapping argument provides access to the size, shape, linetype and linewidth aesthetics within the gg_* function.

penguins |> 
  gg_point(
    x = flipper_length_mm, 
    y = body_mass_g, 
    col = species,
    mapping = aes(shape = species),
  ) +
  labs(shape = "Species")

5. Use delayed evaluation

As the x, y, col and alpha aesthetic arguments require a unquoted variable, you cannot apply a function to these. However, you can for aesthetics within the mapping argument. This is useful for delayed evaluation with the after_stat function.

penguins |>
  gg_histogram(
    x = flipper_length_mm,
    mapping = aes(y = after_stat(density)),
    facet = species,
  )

faithfuld |>
  gg_contour(
    x = waiting,
    y = eruptions,
    z = density,
    mapping = aes(colour = after_stat(level)),
    bins = 8,
  )

6. Add contrasting dark or light text on polygons

A method was developed by @teunbrand to colour text on polygons using a dark or light colour, which is determined based on the underlying polygon colour.

contrast <- function(col_pal, 
                     col_pal_dark = pal_light_mode["text"], 
                     col_pal_light = pal_light_mode["panel"]) {
  
    out <- rep(col_pal_dark, length(col_pal))
    light <- farver::get_channel(col_pal, "l", space = "hcl")
    out[light < 50] <- col_pal_light
    out
  }

aes_contrast <- aes(colour = after_scale(contrast(fill)))

penguins |>
  count(species, sex) |> 
  gg_col(
    x = sex,
    y = n,
    col = species,
    col_pal = c("#0095A8", "#112E51", "#FF7043"),
    position = position_dodge2(preserve = "single"),
    width = 0.75, 
    x_labels = \(x) str_to_sentence(x),
  ) +
  geom_text(
    mapping = aes(y = n - (max(n * 0.04)), label = n, !!!aes_contrast),
    position = position_dodge2(width = 0.75, preserve = "single"),
    size = 3.53,
    show.legend = FALSE,
  )

mtcars |> 
  corrr::correlate() |> 
  corrr::stretch() |> 
  mutate(across(c(x, y), str_to_sentence)) |> 
  gg_tile(
    x = x, 
    y = y,
    col = r,
    x_title = "", 
    y_title = "", 
    x_expand = c(0, 0), 
    y_expand = c(0, 0),
    col_pal_na = pal_light_mode["plot"],
    col_limits = c(-1, 1),
    col_rescale = scales::rescale(c(-1, 0, 1)),
    col_title = "r",
  ) +
  geom_text(
    mapping = aes(label = round(r, 1), !!!aes_contrast),
    size = 3.53,
    show.legend = FALSE,
  )

David Hodge