feat: Add header_font_family_fallback

Fixes #41

Author: gadenbuie

NEWS.md

@@ -4,6 +4,8 @@
 
 - .pull-right[] now clears floats just for its immediate sibling
 
+- Add `header_font_family_fallback` to control fallback fonts for headings (thanks @mattwarkentin, #41)
+
 # xaringanthemer 0.3.0
 
 * Adds `theme_xaringan()`, a ggplot2 theme that automatically uses the colors

R/style_duo.R

@@ -236,6 +236,11 @@
 #'   `h1, h2, h3` elements. Accepts CSS
 #'   [font-weight](https://developer.mozilla.org/en-US/docs/Web/CSS/font-weight)
 #'   property values.
+#' @param header_font_family_fallback Header Font Family Fallback. Defaults to
+#'   Georgia, serif. Modifies the `h1, h2, h3` elements. The value of this
+#'   variable is also stored as a CSS variable that can be referenced with
+#'   `var(--header-font-family-fallback)` in any argument of a style function
+#'   or in custom CSS.
 #' @param header_font_url Header Font URL. Defaults to
 #'   `xaringanthemer_font_default("header_font_url")`. Modifies the
 #'   `@import url` elements.
@@ -321,6 +326,7 @@ style_duo <- function(
   header_font_google = NULL,
   header_font_family = xaringanthemer_font_default("header_font_family"),
   header_font_weight = xaringanthemer_font_default("header_font_weight"),
+  header_font_family_fallback = "Georgia, serif",
   header_font_url = xaringanthemer_font_default("header_font_url"),
   code_font_google = NULL,
   code_font_family = xaringanthemer_font_default("code_font_family"),

R/style_duo_accent.R

@@ -248,6 +248,11 @@
 #'   `h1, h2, h3` elements. Accepts CSS
 #'   [font-weight](https://developer.mozilla.org/en-US/docs/Web/CSS/font-weight)
 #'   property values.
+#' @param header_font_family_fallback Header Font Family Fallback. Defaults to
+#'   Georgia, serif. Modifies the `h1, h2, h3` elements. The value of this
+#'   variable is also stored as a CSS variable that can be referenced with
+#'   `var(--header-font-family-fallback)` in any argument of a style function
+#'   or in custom CSS.
 #' @param header_font_url Header Font URL. Defaults to
 #'   `xaringanthemer_font_default("header_font_url")`. Modifies the
 #'   `@import url` elements.
@@ -335,6 +340,7 @@ style_duo_accent <- function(
   header_font_google = NULL,
   header_font_family = xaringanthemer_font_default("header_font_family"),
   header_font_weight = xaringanthemer_font_default("header_font_weight"),
+  header_font_family_fallback = "Georgia, serif",
   header_font_url = xaringanthemer_font_default("header_font_url"),
   code_font_google = NULL,
   code_font_family = xaringanthemer_font_default("code_font_family"),

R/style_duo_accent_inverse.R

@@ -249,6 +249,11 @@
 #'   `h1, h2, h3` elements. Accepts CSS
 #'   [font-weight](https://developer.mozilla.org/en-US/docs/Web/CSS/font-weight)
 #'   property values.
+#' @param header_font_family_fallback Header Font Family Fallback. Defaults to
+#'   Georgia, serif. Modifies the `h1, h2, h3` elements. The value of this
+#'   variable is also stored as a CSS variable that can be referenced with
+#'   `var(--header-font-family-fallback)` in any argument of a style function
+#'   or in custom CSS.
 #' @param header_font_url Header Font URL. Defaults to
 #'   `xaringanthemer_font_default("header_font_url")`. Modifies the
 #'   `@import url` elements.
@@ -336,6 +341,7 @@ style_duo_accent_inverse <- function(
   header_font_google = NULL,
   header_font_family = xaringanthemer_font_default("header_font_family"),
   header_font_weight = xaringanthemer_font_default("header_font_weight"),
+  header_font_family_fallback = "Georgia, serif",
   header_font_url = xaringanthemer_font_default("header_font_url"),
   code_font_google = NULL,
   code_font_family = xaringanthemer_font_default("code_font_family"),

R/style_mono_accent.R

@@ -239,6 +239,11 @@
 #'   `h1, h2, h3` elements. Accepts CSS
 #'   [font-weight](https://developer.mozilla.org/en-US/docs/Web/CSS/font-weight)
 #'   property values.
+#' @param header_font_family_fallback Header Font Family Fallback. Defaults to
+#'   Georgia, serif. Modifies the `h1, h2, h3` elements. The value of this
+#'   variable is also stored as a CSS variable that can be referenced with
+#'   `var(--header-font-family-fallback)` in any argument of a style function
+#'   or in custom CSS.
 #' @param header_font_url Header Font URL. Defaults to
 #'   `xaringanthemer_font_default("header_font_url")`. Modifies the
 #'   `@import url` elements.
@@ -325,6 +330,7 @@ style_mono_accent <- function(
   header_font_google = NULL,
   header_font_family = xaringanthemer_font_default("header_font_family"),
   header_font_weight = xaringanthemer_font_default("header_font_weight"),
+  header_font_family_fallback = "Georgia, serif",
   header_font_url = xaringanthemer_font_default("header_font_url"),
   code_font_google = NULL,
   code_font_family = xaringanthemer_font_default("code_font_family"),

R/style_mono_accent_inverse.R

@@ -240,6 +240,11 @@
 #'   `h1, h2, h3` elements. Accepts CSS
 #'   [font-weight](https://developer.mozilla.org/en-US/docs/Web/CSS/font-weight)
 #'   property values.
+#' @param header_font_family_fallback Header Font Family Fallback. Defaults to
+#'   Georgia, serif. Modifies the `h1, h2, h3` elements. The value of this
+#'   variable is also stored as a CSS variable that can be referenced with
+#'   `var(--header-font-family-fallback)` in any argument of a style function
+#'   or in custom CSS.
 #' @param header_font_url Header Font URL. Defaults to
 #'   `xaringanthemer_font_default("header_font_url")`. Modifies the
 #'   `@import url` elements.
@@ -326,6 +331,7 @@ style_mono_accent_inverse <- function(
   header_font_google = NULL,
   header_font_family = xaringanthemer_font_default("header_font_family"),
   header_font_weight = xaringanthemer_font_default("header_font_weight"),
+  header_font_family_fallback = "Georgia, serif",
   header_font_url = xaringanthemer_font_default("header_font_url"),
   code_font_google = NULL,
   code_font_family = xaringanthemer_font_default("code_font_family"),

R/style_mono_dark.R

@@ -241,6 +241,11 @@
 #'   `h1, h2, h3` elements. Accepts CSS
 #'   [font-weight](https://developer.mozilla.org/en-US/docs/Web/CSS/font-weight)
 #'   property values.
+#' @param header_font_family_fallback Header Font Family Fallback. Defaults to
+#'   Georgia, serif. Modifies the `h1, h2, h3` elements. The value of this
+#'   variable is also stored as a CSS variable that can be referenced with
+#'   `var(--header-font-family-fallback)` in any argument of a style function
+#'   or in custom CSS.
 #' @param header_font_url Header Font URL. Defaults to
 #'   `xaringanthemer_font_default("header_font_url")`. Modifies the
 #'   `@import url` elements.
@@ -327,6 +332,7 @@ style_mono_dark <- function(
   header_font_google = NULL,
   header_font_family = xaringanthemer_font_default("header_font_family"),
   header_font_weight = xaringanthemer_font_default("header_font_weight"),
+  header_font_family_fallback = "Georgia, serif",
   header_font_url = xaringanthemer_font_default("header_font_url"),
   code_font_google = NULL,
   code_font_family = xaringanthemer_font_default("code_font_family"),

R/style_mono_light.R

@@ -241,6 +241,11 @@
 #'   `h1, h2, h3` elements. Accepts CSS
 #'   [font-weight](https://developer.mozilla.org/en-US/docs/Web/CSS/font-weight)
 #'   property values.
+#' @param header_font_family_fallback Header Font Family Fallback. Defaults to
+#'   Georgia, serif. Modifies the `h1, h2, h3` elements. The value of this
+#'   variable is also stored as a CSS variable that can be referenced with
+#'   `var(--header-font-family-fallback)` in any argument of a style function
+#'   or in custom CSS.
 #' @param header_font_url Header Font URL. Defaults to
 #'   `xaringanthemer_font_default("header_font_url")`. Modifies the
 #'   `@import url` elements.
@@ -327,6 +332,7 @@ style_mono_light <- function(
   header_font_google = NULL,
   header_font_family = xaringanthemer_font_default("header_font_family"),
   header_font_weight = xaringanthemer_font_default("header_font_weight"),
+  header_font_family_fallback = "Georgia, serif",
   header_font_url = xaringanthemer_font_default("header_font_url"),
   code_font_google = NULL,
   code_font_family = xaringanthemer_font_default("code_font_family"),

R/style_solarized_dark.R

@@ -226,6 +226,11 @@
 #'   `h1, h2, h3` elements. Accepts CSS
 #'   [font-weight](https://developer.mozilla.org/en-US/docs/Web/CSS/font-weight)
 #'   property values.
+#' @param header_font_family_fallback Header Font Family Fallback. Defaults to
+#'   Georgia, serif. Modifies the `h1, h2, h3` elements. The value of this
+#'   variable is also stored as a CSS variable that can be referenced with
+#'   `var(--header-font-family-fallback)` in any argument of a style function
+#'   or in custom CSS.
 #' @param header_font_url Header Font URL. Defaults to
 #'   `xaringanthemer_font_default("header_font_url")`. Modifies the
 #'   `@import url` elements.
@@ -309,6 +314,7 @@ style_solarized_dark <- function(
   header_font_google = NULL,
   header_font_family = xaringanthemer_font_default("header_font_family"),
   header_font_weight = xaringanthemer_font_default("header_font_weight"),
+  header_font_family_fallback = "Georgia, serif",
   header_font_url = xaringanthemer_font_default("header_font_url"),
   code_font_google = NULL,
   code_font_family = xaringanthemer_font_default("code_font_family"),

R/style_solarized_light.R

@@ -226,6 +226,11 @@
 #'   `h1, h2, h3` elements. Accepts CSS
 #'   [font-weight](https://developer.mozilla.org/en-US/docs/Web/CSS/font-weight)
 #'   property values.
+#' @param header_font_family_fallback Header Font Family Fallback. Defaults to
+#'   Georgia, serif. Modifies the `h1, h2, h3` elements. The value of this
+#'   variable is also stored as a CSS variable that can be referenced with
+#'   `var(--header-font-family-fallback)` in any argument of a style function
+#'   or in custom CSS.
 #' @param header_font_url Header Font URL. Defaults to
 #'   `xaringanthemer_font_default("header_font_url")`. Modifies the
 #'   `@import url` elements.
@@ -309,6 +314,7 @@ style_solarized_light <- function(
   header_font_google = NULL,
   header_font_family = xaringanthemer_font_default("header_font_family"),
   header_font_weight = xaringanthemer_font_default("header_font_weight"),
+  header_font_family_fallback = "Georgia, serif",
   header_font_url = xaringanthemer_font_default("header_font_url"),
   code_font_google = NULL,
   code_font_family = xaringanthemer_font_default("code_font_family"),