Fix #538

vignettes/articles/3_go_further-Rmd.Rmd

@@ -284,35 +284,47 @@ p1 / p2
 
 ### 8. Add auto-contrast text on polygons
 
-Text labels can be coloured based on the lightness/darkness of underlying polygons using a trick documented by [@teunbrand](https://github.com/teunbrand/ggplot_tricks). It requires `geom_text` to include the `show.legend = FALSE` argument. 
+Text labels can be coloured based on the lightness/darkness of underlying polygons using code developed by [@teunbrand](https://github.com/teunbrand/ggplot_tricks). It requires `geom_text` to include the `show.legend = FALSE` argument. 
 
 ```{r}
-contrast <- function(colour) {
-  out   <- rep("#121b24", length(colour)) #use "#bbccdd" for dark_mode
-  light <- farver::get_channel(colour, "l", space = "hcl")
-  out[light < 50] <- "#fcfdfe" #use "#1f2f3e" for dark_mode 
-  out
+contrast <-
+  function(pal,
+           pal_dark = "#121b24",
+           pal_light = "#fcfdfe") {
+    
+    out   <- rep(pal_dark, length(pal))
+    light <- farver::get_channel(pal, "l", space = "hcl")
+    out[light < 50] <- pal_light
+    out
+  }
+
+aes_contrast <- {
+  aes(colour = after_scale(contrast(fill)))
 }
 
-penguins2 |>
-  group_by(sex, species) |>
-  summarise(across(flipper_length_mm, \(x) mean(x, na.rm = TRUE))) |>
-  ungroup() |>
+palmerpenguins::penguins |>
+  count(species, sex) |> 
   gg_col(
-    x = flipper_length_mm,
-    y = sex,
+    x = sex,
+    y = n,
     col = species,
-    position = "dodge",
-    width = 0.75) +
+    pal = c("#0095A8", "#112E51", "#FF7043"),
+    width = 0.75, 
+    position = position_dodge2(preserve = "single"),
+    x_labels = \(x) str_to_sentence(x), 
+    col_legend_place = "right",
+  ) +
   geom_text(
     aes(
-      x = flipper_length_mm - (max(flipper_length_mm) * 0.05),
-      label = round(flipper_length_mm, 0), 
-      !!!aes(colour = after_scale(contrast((fill))))
+      y = n - (max(n * 0.04)),
+      label = n, 
+      !!!aes_contrast, 
+      # !!!aes(colour = after_scale(contrast(fill))),
     ),
-    show.legend = FALSE,
+    position = position_dodge2(width = 0.75, preserve = "single"),
     size = 3.53,
-    position = position_dodge(width = 0.75)) 
+    show.legend = FALSE,
+  ) 
 ```
 
 ```{r}
@@ -334,8 +346,11 @@ mtcars |>
     col_title = "r") +
   geom_text(
     aes(label = round(r, 1),
-        !!!aes(colour = after_scale(contrast(fill)))), 
+      !!!aes_contrast, 
+      # !!!aes(colour = after_scale(contrast(fill))),
+    ),
+    size = 3.53,
     show.legend = FALSE,
-    size = 3.53)
+  )
 ```