Add apply_alpha and choose_dark_or_light functions

NAMESPACE

 # Generated by roxygen2: do not edit by hand
 
+export(apply_alpha)
+export(choose_dark_or_light)
 export(darken_color)
 export(duo_theme)
 export(google_font)

R/mono_accent.R

 #' @param title_slide_text_color Title Slide Text Color, defaults to `inverse_text_color`
 #' @param title_slide_background_color Title Slide Background Color, defaults to `inverse_background_color`
 #' @param title_slide_background_image Title Slide Background Image URL, defaults to NA
-#' @param left_column_subtle_color Left Column Text (not last), defaults to `lighten_color(base_color, 0.5)`
+#' @param left_column_subtle_color Left Column Text (not last), defaults to `apply_alpha(base_color, 0.6)`
 #' @param left_column_selected_color Left Column Current Selection, defaults to `base_color`
-#' @param blockquote_left_color Blockquote Left Border Color, defaults to `lighten_color(base_color, 0.5)`
+#' @param blockquote_left_color Blockquote Left Border Color, defaults to `apply_alpha(base_color, 0.5)`
 #' @param table_border_color Table top/bottom border, defaults to #666
 #' @param table_row_border_color Table row inner bottom border, defaults to #ddd
 #' @param table_row_even_background_color Table Even Row Background Color, defaults to `lighten_color(base_color, 0.7)`
   title_slide_text_color = inverse_text_color,
   title_slide_background_color = inverse_background_color,
   title_slide_background_image = NA,
-  left_column_subtle_color = lighten_color(base_color, 0.5),
+  left_column_subtle_color = apply_alpha(base_color, 0.6),
   left_column_selected_color = base_color,
-  blockquote_left_color = lighten_color(base_color, 0.5),
+  blockquote_left_color = apply_alpha(base_color, 0.5),
   table_border_color = "#666",
   table_row_border_color = "#ddd",
   table_row_even_background_color = lighten_color(base_color, 0.7),

R/mono_accent_inverse.R

 #' @param title_slide_text_color Title Slide Text Color, defaults to `inverse_text_color`
 #' @param title_slide_background_color Title Slide Background Color, defaults to `inverse_background_color`
 #' @param title_slide_background_image Title Slide Background Image URL, defaults to NA
-#' @param left_column_subtle_color Left Column Text (not last), defaults to `darken_color(base_color, 0.5)`
+#' @param left_column_subtle_color Left Column Text (not last), defaults to `apply_alpha(base_color, 0.6)`
 #' @param left_column_selected_color Left Column Current Selection, defaults to `base_color`
-#' @param blockquote_left_color Blockquote Left Border Color, defaults to `darken_color(base_color, 0.5)`
+#' @param blockquote_left_color Blockquote Left Border Color, defaults to `apply_alpha(base_color, 0.5)`
 #' @param table_border_color Table top/bottom border, defaults to #666
 #' @param table_row_border_color Table row inner bottom border, defaults to #ddd
 #' @param table_row_even_background_color Table Even Row Background Color, defaults to `darken_color(base_color, 0.7)`
   title_slide_text_color = inverse_text_color,
   title_slide_background_color = inverse_background_color,
   title_slide_background_image = NA,
-  left_column_subtle_color = darken_color(base_color, 0.5),
+  left_column_subtle_color = apply_alpha(base_color, 0.6),
   left_column_selected_color = base_color,
-  blockquote_left_color = darken_color(base_color, 0.5),
+  blockquote_left_color = apply_alpha(base_color, 0.5),
   table_border_color = "#666",
   table_row_border_color = "#ddd",
   table_row_even_background_color = darken_color(base_color, 0.7),

R/mono_dark.R

 #' @param title_slide_text_color Title Slide Text Color, defaults to `inverse_text_color`
 #' @param title_slide_background_color Title Slide Background Color, defaults to `inverse_background_color`
 #' @param title_slide_background_image Title Slide Background Image URL, defaults to NA
-#' @param left_column_subtle_color Left Column Text (not last), defaults to `darken_color(base_color, 0.5)`
+#' @param left_column_subtle_color Left Column Text (not last), defaults to `apply_alpha(base_color, 0.6)`
 #' @param left_column_selected_color Left Column Current Selection, defaults to `base_color`
-#' @param blockquote_left_color Blockquote Left Border Color, defaults to `darken_color(base_color, 0.5)`
+#' @param blockquote_left_color Blockquote Left Border Color, defaults to `apply_alpha(base_color, 0.5)`
 #' @param table_border_color Table top/bottom border, defaults to #666
 #' @param table_row_border_color Table row inner bottom border, defaults to #ddd
 #' @param table_row_even_background_color Table Even Row Background Color, defaults to `darken_color(base_color, 0.7)`
   title_slide_text_color = inverse_text_color,
   title_slide_background_color = inverse_background_color,
   title_slide_background_image = NA,
-  left_column_subtle_color = darken_color(base_color, 0.5),
+  left_column_subtle_color = apply_alpha(base_color, 0.6),
   left_column_selected_color = base_color,
-  blockquote_left_color = darken_color(base_color, 0.5),
+  blockquote_left_color = apply_alpha(base_color, 0.5),
   table_border_color = "#666",
   table_row_border_color = "#ddd",
   table_row_even_background_color = darken_color(base_color, 0.7),

R/mono_light.R

 #' @param title_slide_text_color Title Slide Text Color, defaults to `inverse_text_color`
 #' @param title_slide_background_color Title Slide Background Color, defaults to `inverse_background_color`
 #' @param title_slide_background_image Title Slide Background Image URL, defaults to NA
-#' @param left_column_subtle_color Left Column Text (not last), defaults to `lighten_color(base_color, 0.5)`
+#' @param left_column_subtle_color Left Column Text (not last), defaults to `apply_alpha(base_color, 0.6)`
 #' @param left_column_selected_color Left Column Current Selection, defaults to `base_color`
-#' @param blockquote_left_color Blockquote Left Border Color, defaults to `lighten_color(base_color, 0.5)`
+#' @param blockquote_left_color Blockquote Left Border Color, defaults to `apply_alpha(base_color, 0.5)`
 #' @param table_border_color Table top/bottom border, defaults to #666
 #' @param table_row_border_color Table row inner bottom border, defaults to #ddd
 #' @param table_row_even_background_color Table Even Row Background Color, defaults to `lighten_color(base_color, 0.8)`
   title_slide_text_color = inverse_text_color,
   title_slide_background_color = inverse_background_color,
   title_slide_background_image = NA,
-  left_column_subtle_color = lighten_color(base_color, 0.5),
+  left_column_subtle_color = apply_alpha(base_color, 0.6),
   left_column_selected_color = base_color,
-  blockquote_left_color = lighten_color(base_color, 0.5),
+  blockquote_left_color = apply_alpha(base_color, 0.5),
   table_border_color = "#666",
   table_row_border_color = "#ddd",
   table_row_even_background_color = lighten_color(base_color, 0.8),

R/theme_settings.R

   inverse_background_color        = "{base_color}",
   inverse_text_color              = "{white_color}",
   inverse_header_color            = "{white_color}",
-  left_column_subtle_color        = "{lighten_color(base_color, 0.5)}",
+  left_column_subtle_color        = "{apply_alpha(base_color, 0.6)}",
   left_column_selected_color      = "{base_color}",
-  blockquote_left_color           = "{lighten_color(base_color, 0.5)}",
+  blockquote_left_color           = "{apply_alpha(base_color, 0.5)}",
   table_row_even_background_color = "{lighten_color(base_color, 0.8)}")
 
 template_mono_dark <- tibble::tribble(
   inverse_background_color        = "{base_color}",
   inverse_text_color              = "{black_color}",
   inverse_header_color            = "{black_color}",
-  left_column_subtle_color        = "{darken_color(base_color, 0.5)}",
+  left_column_subtle_color        = "{apply_alpha(base_color, 0.6)}",
   left_column_selected_color      = "{base_color}",
-  blockquote_left_color           = "{darken_color(base_color, 0.5)}",
+  blockquote_left_color           = "{apply_alpha(base_color, 0.5)}",
   table_row_even_background_color = "{darken_color(base_color, 0.7)}")
 
 template_mono_accent <- tibble::tribble(
   inverse_background_color        = "{base_color}",
   inverse_text_color              = "{white_color}",
   inverse_header_color            = "{white_color}",
-  left_column_subtle_color        = "{lighten_color(base_color, 0.5)}",
+  left_column_subtle_color        = "{apply_alpha(base_color, 0.6)}",
   left_column_selected_color      = "{base_color}",
-  blockquote_left_color           = "{lighten_color(base_color, 0.5)}",
+  blockquote_left_color           = "{apply_alpha(base_color, 0.5)}",
   table_row_even_background_color = "{lighten_color(base_color, 0.7)}")
 
 template_mono_accent_inverse <- tibble::tribble(
   inverse_background_color        = "{base_color}",
   inverse_text_color              = "{black_color}",
   inverse_header_color            = "{black_color}",
-  left_column_subtle_color        = "{darken_color(base_color, 0.5)}",
+  left_column_subtle_color        = "{apply_alpha(base_color, 0.6)}",
   left_column_selected_color      = "{base_color}",
-  blockquote_left_color           = "{darken_color(base_color, 0.5)}",
+  blockquote_left_color           = "{apply_alpha(base_color, 0.5)}",
   table_row_even_background_color = "{darken_color(base_color, 0.7)}")

R/utils.R

   rgb(color_rgb[1], color_rgb[2], color_rgb[3], maxColorValue = 255)
 }
 
-adjust_value_color <- function(color_hext, strength = 0.5) {
+#' @export
+apply_alpha <- function(color_hex, opacity = 0.5) {
+  paste0(color_hex, as.hexmode(round(255*opacity, 0)))
+}
+
+adjust_value_color <- function(color_hex, strength = 0.5) {
   color_hsv <- rgb2hsv(col2rgb(color_hex))[, 1]
   color_hsv['v'] <- strength
   hsv(color_hsv[1], color_hsv[2], color_hsv[3])
 }
 
+#' Choose dark or light color
+#'
+#' Takes a color input as `x` and returns either the black or white color (or
+#' expression) if dark or light text should be used over the input color for
+#' best contrast. Follows W3C Recommendations.
+#'
+#' @references <https://stackoverflow.com/a/3943023/2022615>
+#' @param x The background color
+#' @param black Text or foreground color, e.g. "#222" or
+#' `substitute(darken_color(x, 0.8))`, if black text provides the best contrast.
+#' @param white Text or foreground color or expression, e.g. "#EEE" or
+#' `substitute(lighten_color(x, 0.8))`, if white text provides the best contrast.
+#' @export
+choose_dark_or_light <- function(x, black = "#000", white = "#FFF") {
+  # x = color_hex
+  # black <- substitute(black)
+  # white <- substitute(white)
+  color_rgb <- col2rgb(x)[, 1]
+  # from https://stackoverflow.com/a/3943023/2022615
+  color_rgb <- color_rgb / 255
+  color_rgb[color_rgb <= 0.03928] <- color_rgb[color_rgb <= 0.03928]/12.92
+  color_rgb[color_rgb > 0.03928] <- ((color_rgb[color_rgb > 0.03928] + 0.055)/1.055)^2.4
+  lum <- t(c(0.2126, 0.7152, 0.0722)) %*% color_rgb
+  if (lum[1, 1] > 0.179) eval(black) else eval(white)
+}
+
 #' @keywords internal
 call_write_xaringan_theme <- function() {
   paste0("write_xaringan_theme(",

man/choose_dark_or_light.Rd

+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/utils.R
+\name{choose_dark_or_light}
+\alias{choose_dark_or_light}
+\title{Choose dark or light color}
+\usage{
+choose_dark_or_light(x, black = "#000", white = "#FFF")
+}
+\arguments{
+\item{x}{The background color}
+
+\item{black}{Text or foreground color, e.g. "#222" or
+\code{substitute(darken_color(x, 0.8))}, if black text provides the best contrast.}
+
+\item{white}{Text or foreground color or expression, e.g. "#EEE" or
+\code{substitute(lighten_color(x, 0.8))}, if white text provides the best contrast.}
+}
+\description{
+Takes a color input as \code{x} and returns either the black or white color (or
+expression) if dark or light text should be used over the input color for
+best contrast. Follows W3C Recommendations.
+}
+\references{
+\url{https://stackoverflow.com/a/3943023/2022615}
+}

man/mono_accent.Rd

   title_slide_text_color = inverse_text_color,
   title_slide_background_color = inverse_background_color,
   title_slide_background_image = NA,
-  left_column_subtle_color = lighten_color(base_color, 0.5),
+  left_column_subtle_color = apply_alpha(base_color, 0.6),
   left_column_selected_color = base_color,
-  blockquote_left_color = lighten_color(base_color, 0.5),
+  blockquote_left_color = apply_alpha(base_color, 0.5),
   table_border_color = "#666", table_row_border_color = "#ddd",
   table_row_even_background_color = lighten_color(base_color, 0.7),
   text_font_google = NULL, text_font_family = "'Droid Serif'",
 
 \item{title_slide_background_image}{Title Slide Background Image URL, defaults to NA}
 
-\item{left_column_subtle_color}{Left Column Text (not last), defaults to \code{lighten_color(base_color, 0.5)}}
+\item{left_column_subtle_color}{Left Column Text (not last), defaults to \code{apply_alpha(base_color, 0.6)}}
 
 \item{left_column_selected_color}{Left Column Current Selection, defaults to \code{base_color}}
 
-\item{blockquote_left_color}{Blockquote Left Border Color, defaults to \code{lighten_color(base_color, 0.5)}}
+\item{blockquote_left_color}{Blockquote Left Border Color, defaults to \code{apply_alpha(base_color, 0.5)}}
 
 \item{table_border_color}{Table top/bottom border, defaults to #666}
 

man/mono_accent_inverse.Rd

   title_slide_text_color = inverse_text_color,
   title_slide_background_color = inverse_background_color,
   title_slide_background_image = NA,
-  left_column_subtle_color = darken_color(base_color, 0.5),
+  left_column_subtle_color = apply_alpha(base_color, 0.6),
   left_column_selected_color = base_color,
-  blockquote_left_color = darken_color(base_color, 0.5),
+  blockquote_left_color = apply_alpha(base_color, 0.5),
   table_border_color = "#666", table_row_border_color = "#ddd",
   table_row_even_background_color = darken_color(base_color, 0.7),
   text_font_google = NULL, text_font_family = "'Droid Serif'",
 
 \item{title_slide_background_image}{Title Slide Background Image URL, defaults to NA}
 
-\item{left_column_subtle_color}{Left Column Text (not last), defaults to \code{darken_color(base_color, 0.5)}}
+\item{left_column_subtle_color}{Left Column Text (not last), defaults to \code{apply_alpha(base_color, 0.6)}}
 
 \item{left_column_selected_color}{Left Column Current Selection, defaults to \code{base_color}}
 
-\item{blockquote_left_color}{Blockquote Left Border Color, defaults to \code{darken_color(base_color, 0.5)}}
+\item{blockquote_left_color}{Blockquote Left Border Color, defaults to \code{apply_alpha(base_color, 0.5)}}
 
 \item{table_border_color}{Table top/bottom border, defaults to #666}
 

man/mono_dark.Rd

   title_slide_text_color = inverse_text_color,
   title_slide_background_color = inverse_background_color,
   title_slide_background_image = NA,
-  left_column_subtle_color = darken_color(base_color, 0.5),
+  left_column_subtle_color = apply_alpha(base_color, 0.6),
   left_column_selected_color = base_color,
-  blockquote_left_color = darken_color(base_color, 0.5),
+  blockquote_left_color = apply_alpha(base_color, 0.5),
   table_border_color = "#666", table_row_border_color = "#ddd",
   table_row_even_background_color = darken_color(base_color, 0.7),
   text_font_google = NULL, text_font_family = "'Droid Serif'",
 
 \item{title_slide_background_image}{Title Slide Background Image URL, defaults to NA}
 
-\item{left_column_subtle_color}{Left Column Text (not last), defaults to \code{darken_color(base_color, 0.5)}}
+\item{left_column_subtle_color}{Left Column Text (not last), defaults to \code{apply_alpha(base_color, 0.6)}}
 
 \item{left_column_selected_color}{Left Column Current Selection, defaults to \code{base_color}}
 
-\item{blockquote_left_color}{Blockquote Left Border Color, defaults to \code{darken_color(base_color, 0.5)}}
+\item{blockquote_left_color}{Blockquote Left Border Color, defaults to \code{apply_alpha(base_color, 0.5)}}
 
 \item{table_border_color}{Table top/bottom border, defaults to #666}
 

man/mono_light.Rd

   title_slide_text_color = inverse_text_color,
   title_slide_background_color = inverse_background_color,
   title_slide_background_image = NA,
-  left_column_subtle_color = lighten_color(base_color, 0.5),
+  left_column_subtle_color = apply_alpha(base_color, 0.6),
   left_column_selected_color = base_color,
-  blockquote_left_color = lighten_color(base_color, 0.5),
+  blockquote_left_color = apply_alpha(base_color, 0.5),
   table_border_color = "#666", table_row_border_color = "#ddd",
   table_row_even_background_color = lighten_color(base_color, 0.8),
   text_font_google = NULL, text_font_family = "'Droid Serif'",
 
 \item{title_slide_background_image}{Title Slide Background Image URL, defaults to NA}
 
-\item{left_column_subtle_color}{Left Column Text (not last), defaults to \code{lighten_color(base_color, 0.5)}}
+\item{left_column_subtle_color}{Left Column Text (not last), defaults to \code{apply_alpha(base_color, 0.6)}}
 
 \item{left_column_selected_color}{Left Column Current Selection, defaults to \code{base_color}}
 
-\item{blockquote_left_color}{Blockquote Left Border Color, defaults to \code{lighten_color(base_color, 0.5)}}
+\item{blockquote_left_color}{Blockquote Left Border Color, defaults to \code{apply_alpha(base_color, 0.5)}}
 
 \item{table_border_color}{Table top/bottom border, defaults to #666}