type_text(labeller = ...)

NEWS.md

@@ -153,6 +153,10 @@ Theme fixes:
     and drawing them as standalone bars. This is useful for Likert plots, where
     you want to show a neutral categories (e.g., "Unsure") apart from the 
     diverging stack. Thanks to @strengejacke for the suggestion.
+- `type_text()` (and `type = "text"`) gains a `labeller` argument that is passed
+  to `tinylabel()` for formatting the text labels. This is useful for ensuring
+  that text annotations match a formatted axis, e.g. `labeller = "%"` to display
+  the labels as percentages. (#620 @grantmcdermott)
 
 ### Bug fixes
 

R/type_text.R

@@ -6,6 +6,11 @@
 #' @param labels Character vector of length `1` or the same length as the
 #'   number of `x`,`y` coordinates. If left as `NULL`, then the labels will
 #'   automatically inherit the corresponding `y` values. See Examples.
+#' @param labeller A formatting function (or convenience string) passed to
+#'   [`tinylabel`] for formatting the `labels`. Useful for ensuring that the
+#'   text labels match the formatting of an axis, e.g. `labeller = "%"` to
+#'   display the labels as percentages. Default is `NULL`, i.e. no formatting.
+#'   See Examples.
 #' @param family The name of a font family. Default of `NULL` means that the
 #' family will be the same as the main plot text, following
 #' \code{\link[graphics]{par}}. Note that if a `family` argument is provided,
@@ -53,9 +58,15 @@
 #'   )
 #' )
 #'
+#' # use `labeller` to format the labels, e.g. to match a formatted axis
+#' d = data.frame(x = c("A", "B"), y = c(0.5, 0.8))
+#' tinyplot(y ~ x, data = d, type = "bar", ylim = c(0, 1), yaxl = "%")
+#' tinyplot_add(type = type_text(labeller = "%", adj = c(0.5, -0.5)))
+#'
 #' @export
 type_text = function(
   labels = NULL,
+  labeller = NULL,
   adj = NULL,
   pos = NULL,
   offset = 0.5,
@@ -77,27 +88,30 @@ type_text = function(
       xpd = xpd,
       srt = srt
     ),
-    data = data_text(labels = labels, clim = clim),
+    data = data_text(labels = labels, labeller = labeller, clim = clim),
     name = "text"
   )
   class(out) = "tinyplot_type"
   return(out)
 }
 
-data_text = function(labels = NULL, clim = c(0.5, 2.5)) {
+data_text = function(labels = NULL, labeller = NULL, clim = c(0.5, 2.5)) {
   fun = function(settings, ...) {
     env2env(settings, environment(), "datapoints")
-    
+
     # Store clim for bubble() function
     settings$clim = clim
-    
+
     if (is.null(labels)) {
       labels = datapoints$y
     }
     if (length(labels) != 1 && length(labels) != nrow(datapoints)) {
       msg = sprintf("`labels` must be of length 1 or %s.", nrow(datapoints))
       stop(msg, call. = FALSE)
     }
+    if (!is.null(labeller)) {
+      labels = tinylabel(labels, labeller)
+    }
     datapoints$labels = labels
     if (is.factor(datapoints$x)) {
       datapoints$x = as.numeric(datapoints$x)

inst/tinytest/test-type_text.R

@@ -29,3 +29,12 @@ f = function() {
   tinyplot(x, y, labels = z, type = "text")
 }
 expect_snapshot_plot(f, label = "text_single_character")
+
+
+# labeller arg formats text labels, e.g. to match a formatted axis (#617)
+f = function() {
+  d = data.frame(x = c("A", "B"), y = c(0.5, 0.8))
+  tinyplot(y ~ x, data = d, type = "bar", ylim = c(0, 1), yaxl = "%")
+  tinyplot_add(type = type_text(labeller = "%", adj = c(0.5, -0.5)))
+}
+expect_snapshot_plot(f, label = "text_labeller_percent")