Package 'thematic'

Configure auto theming behavior

Description

Auto theming is really only "guaranteed" to work inside of a shiny runtime. In any other context, auto theming is based on a set of heuristics, which won't fit every use case. As a workaround, this function allows one to configure both a preference for specific auto values (e.g., bg, fg, etc) as well as the priority that certain information should receive.

Usage

auto_config(
  bg = NULL,
  fg = NULL,
  accent = NULL,
  font = NULL,
  priority = c("shiny", "config", "bslib", "rstudio")
)

auto_config_set(config)

auto_config_get()

Arguments

bg	a background color.
fg	a foreground color.
accent	a color for making certain graphical markers 'stand out' (e.g., the fitted line color for ggplot2::geom_smooth()). Can be 2 colors for lattice (stroke vs fill accent).
font	a font_spec() object. If missing, font defaults are not altered.
priority	the order of priority to use when resolving auto values. Possible values include: "shiny": use shiny::getCurrentOutputInfo() values (if any) to resolve auto values. "config": use the values provided to this function (if any) to resolve auto values. "bslib": use bslib::bs_get_variables() values (if any) to resolve auto values (only relevant when knitr is in progress). "rstudio": use rstudioapi::getThemeInfo() values (if any) to resolve auto values.
config	a auto_config() object.

Details

Configuring auto theming behavior is especially useful for developers of a custom rmarkdown output document that wish to have more sensible auto theming behavior for users of the document. In particular, by having the output document call auto_config_set() "pre-knit" with the document's styling preferences (and restoring the old defaults "post-knit"), users of the output document can then simply call thematic_on() within their document to use those preferences.

Call this function with no arguments to get the current auto defaults.

Value

a config (list-like) object.

Examples

old_config <- auto_config_set(auto_config("black", "white"))
thematic_with_theme(
  thematic_theme(), {
    plot(1:10, 1:10)
 })
auto_config_set(old_config)

---

Resolve auto values

Description

Resolves 'auto' values based on the current execution environment and configuration (i.e., auto_config_get()).

Usage

auto_resolve_theme(theme)

Arguments

theme

a thematic_theme() object.

Value

The theme object with resolved 'auto' values.

See Also

auto_config_set()

Examples

old_config <- auto_config_set(auto_config(bg = "black", fg = "white"))

# Resolving auto values in local theme objects
theme <- thematic_theme()
theme[c("bg", "fg")]
theme <- auto_resolve_theme(theme)
theme[c("bg", "fg")]

# By default, auto values are resolved when accessing
# global theme options
thematic_on()
thematic_get_option("bg", resolve = FALSE)
thematic_get_option("bg")
thematic_off()

auto_config_set(old_config)

---

Control the directory used for font caching

Description

The default directory used for font caching is system dependent; and thus, not very portable from machine to machine. Use this function to move thematic's cache to a new path. This is primarily useful for making font cache relative to a shiny app directory, so that, when the app is deployed, the cache deploys with it.

Usage

font_cache_set(path, cleanup = FALSE)

Arguments

path	a filepath for the new cachine directory.
cleanup	whether or not to remove font files from the previously used caching directory (after copying to the new location).

Value

Returns the previously used caching directory.

See Also

thematic_on(), font_spec()

Examples

## Not run: 
  font_cache_set("my_app")
  shiny::runApp("my_app")

## End(Not run)

---

Font specification

Description

Specify a collection of font families. The first font family supported by the relevant device (i.e., the device that is open, or will be opened, at plotting time) is used by thematic. If a given font family is not supported by the default, but is a Google Font and install = TRUE, the font will be downloaded, cached, and registered for use the showtext and ragg packages.

Usage

font_spec(
  families = "",
  scale = 1,
  install = is_installed("ragg") || is_installed("showtext"),
  update = FALSE,
  quiet = TRUE
)

Arguments

families	a character vector of font families.
scale	numerical constant applied to font sizes.
install	whether to download and register font families available via Google Fonts (but unavailable to R). After a successful download, fonts are cached (in a directory which can be managed via font_cache_set()), and registered for use with the showtext and ragg packages. If installation fails with a valid internet connection, you may need to fetch the latest Google Font information prior to installation (i.e., set update = TRUE).
update	if TRUE, the latest Google Fonts are fetched and any out-dated font cache is updated. Fetching the latest fonts requires a Google Font API key (one is bundled with the package, but you can set your own via an environment variable, GFONT_KEY).
quiet	whether to suppress download messages.

Value

the input arguments as a list.

See Also

thematic_save_plot(), thematic_on(), font_cache_set()

---

A color-blind safe qualitative colorscale (Okabe-Ito)

Description

This is the default qualitative colorscale in thematic_on()

Usage

okabe_ito(n = NULL)

Arguments

n	number of colors.

Value

a vector of color codes.

References

https://jfly.uni-koeln.de/color/

See Also

thematic_on()

---

Control parameters of the sequential colorscale

Description

Controls the default weighting and direction of the color gradient derived from the fg, bg, and accent color (defined in thematic_on()).

Usage

sequential_gradient(fg_weight = 0.9, bg_weight = 0, fg_low = TRUE, n = 30)

Arguments

fg_weight	a number (between 0 and 1) defining much of the fg color should be mixed into the colorscale.
bg_weight	a number (between 0 and 1) defining much of the bg color should be mixed into the colorscale.
fg_low	if TRUE (the default), the fg color is used for the low end of the colorscale (rather than the high end).
n	number of color codes.

Value

a list of options for passing to the sequential argument of thematic_on().

Examples

# Gradient from fg to accent
fg <- sequential_gradient(1, 0)
thematic_on("black", "white", "salmon", sequential = fg)
ggplot2::qplot(1:10, 1:10, color = 1:10)

# Gradient from accent -> bg
bg <- sequential_gradient(0, 1)
thematic_on("black", "white", "salmon", sequential = bg)
ggplot2::qplot(1:10, 1:10, color = 1:10)

# Gradient from mix(accent, fg, 0.5) -> mix(accent, bg, 0.5)
mix <- sequential_gradient(0.5, 0.5)
thematic_on("black", "white", "salmon", sequential = mix)
ggplot2::qplot(1:10, 1:10, color = 1:10)

# Use fg (instead of bg) for high end of scale
mix_flip <- sequential_gradient(0.5, 0.5, fg_low = FALSE)
thematic_on("black", "white", "salmon", sequential = mix_flip)
ggplot2::qplot(1:10, 1:10, color = 1:10)

---

Enable (or disable) simplified theming of R graphics.

Description

A unified interface for theming ggplot2, base, and lattice graphics based on a handful of styling options. In some cases (most notably in a shiny runtime), these options can automatically resolve to relevant CSS styles (see the "Auto theming" section below).

Usage

thematic_on(
  bg = "auto",
  fg = "auto",
  accent = "auto",
  font = NA,
  sequential = sequential_gradient(),
  qualitative = okabe_ito(),
  inherit = FALSE
)

thematic_off()

thematic_theme(
  bg = "auto",
  fg = "auto",
  accent = "auto",
  font = NA,
  sequential = sequential_gradient(),
  qualitative = okabe_ito(),
  inherit = FALSE
)

thematic_shiny(
  bg = "auto",
  fg = "auto",
  accent = "auto",
  font = NA,
  sequential = sequential_gradient(),
  qualitative = okabe_ito(),
  inherit = FALSE,
  session = shiny::getDefaultReactiveDomain()
)

thematic_rmd(
  bg = "auto",
  fg = "auto",
  accent = "auto",
  font = NA,
  sequential = sequential_gradient(),
  qualitative = okabe_ito(),
  inherit = FALSE
)

Arguments

bg	a background color.
fg	a foreground color.
accent	a color for making certain graphical markers 'stand out' (e.g., the fitted line color for ggplot2::geom_smooth()). Can be 2 colors for lattice (stroke vs fill accent).
font	a font_spec() object. If missing, font defaults are not altered.
sequential	a color palette for graphical markers that encode numeric values. Can be a vector of color codes or a sequential_gradient() object.
qualitative	a color palette for graphical markers that encode qualitative values (won't be used in ggplot2 when the number of data levels exceeds the max allowed colors). Defaults to okabe_ito().
inherit	should non-specified values inherit from the previous theme?
session	see shiny::onStop().

Value

thematic_theme() returns a theme object as a list (which can be activated with thematic_with_theme() or thematic_set_theme()).

thematic_on(), thematic_off(), and thematic_shiny() all return the previous global theme.

Auto theming

The bg, fg, accent, and font arguments all support a value of 'auto', which are all resolved, at plot time, based on the execution environment. In a shiny runtime, resolution of auto values should always work as expect; but in other contexts, auto values may lead to wrong or surprising results. In that case, auto resolution logic can be customized (see auto_config_set() for more details).

Global vs. local theming

thematic_on() enables thematic in a global fashion (that is, it impacts all future plots, up until thematic_off() is called). To use thematic in local fashion, first create a theme with thematic_theme(), then provide it to thematic_with_theme() (or similar). To use thematic in a global fashion up until a shiny app exits, use thematic_shiny() (which cleans up after itself once the next shiny app that exits using shiny::onStop()). To use thematic in a global fashion up until a rmarkdown document finishes rendering, use thematic_rmd().

Color values

Colors (e.g., bg, fg, accent) may be any value understood by col2rgb() or htmltools::parseCssColors() (i.e., may be any valid R or CSS color string).

See Also

sequential_gradient(), thematic_with_theme(), thematic_save_plot()

Examples

# simple dark mode
thematic_on("black", "white")
plot(1:10)
plot(1:10, col = 1:10)
lattice::show.settings()

# use any hex color string
thematic_on("#444444", "#e4e4e4")
plot(1:10)
plot(1:10, col = 1:10)
lattice::show.settings()

# disables thematic (also restores global state)
thematic_off()
plot(1:10)
lattice::show.settings()

thematic_on("darkblue", "skyblue", "orange")
image(volcano)
image(volcano, col = thematic_get_option("sequential"))
lattice::show.settings()
thematic_off()

---

Capture a thematic plot as a saved file

Description

Uses a device to capture the result of an expression (expr) that produces a plot. If default_device() is used, custom fonts (specified through font_spec()) are guaranteed to work, as long as one of either the showtext or ragg package(s) are installed.

Usage

thematic_save_plot(
  expr,
  device = default_device(),
  filename = tempfile(fileext = ".png"),
  ...
)

default_device(type = c("png", "svg", "pdf", "tiff", "jpeg"))

Arguments

expr	an expression that produces a plot.
device	a graphics device to use for capturing the plot.
filename	a filename for the produced plot. The file extension should match the relevant device.
...	arguments passed along to the graphics device.
type	the type of output format

Value

thematic_save_plot() returns the filename of the produced plot and default_device() returns a graphics device function.

Examples

library(thematic)
font <- font_spec("Rock Salt", scale = 1.25)
thematic_on("black", "white", font = font)
file <- thematic_save_plot(plot(1:10), res = 144)
if (interactive()) browseURL(file)

---

Tools for getting and restoring global state

Description

These functions are helpful for getting and/or temporarily activating a thematic_theme().

Usage

thematic_with_theme(theme, expr)

thematic_local_theme(theme, .local_envir = parent.frame())

thematic_set_theme(theme)

thematic_get_theme(resolve = TRUE)

thematic_get_option(name = "", default = NULL, resolve = TRUE)

thematic_get_mixture(amounts = 0.5, default = NULL)

Arguments

theme	a thematic_theme() object (or a return value of thematic_on/thematic_get_theme()) or NULL (in which case thematic_off() is called).
expr	R code that produces a plot.
.local_envir	The environment to use for scoping.
resolve	whether or not 'auto' values should be resolved before returning
name	a theme element name (e.g., fg, bg, etc.)
default	a default value to return in the event no thematic theme is active.
amounts	value(s) between 0 and 1 specifying how much to mix bg (0) and fg (1).

Value

the result of expr.

Functions

• thematic_with_theme(): similar to thematic_on(), but for an single plot.

• thematic_local_theme(): similar to thematic_with_theme(), but de-couples the theme from the plot expression.

• thematic_set_theme(): set a given theme object as the current theme.

• thematic_get_theme(): obtain the current theme.

• thematic_get_option(): obtain a particular theme option (and provide a default if no theme is active).

• thematic_get_mixture(): obtain a mixture of the current theme's bg and fg.

Examples

# Use thematic_with_theme() for a one-time use of thematic
thematic_with_theme(
  thematic_theme("darkblue", "skyblue", accent = "red"),
  plot(1:10, col = thematic_get_option("accent"), pch = 19)
)

# Use thematic_set_theme() if doing something more complicated
# like programming on top thematic (without causing side effects)
my_plot <- function(expr, las = 3, ...) {
  old_theme <- thematic_on("black", "white")
  on.exit(thematic_set_theme(old_theme), add = TRUE)
  opts <- par(las = las)
  on.exit(par(opts), add = TRUE)
  # Imagine some more customization with ...
  force(expr)
}
my_plot(plot(1:10))

thematic_off()
thematic_get_option("bg", "white")
thematic_on(bg = "red")
thematic_get_option("bg", "white")
thematic_off()

thematic_with_theme(
  thematic_theme("darkblue", "skyblue"),
  scales::show_col(thematic_get_mixture(seq(0, 1, by = 0.1)))
)

---