fallback for unit margins

Author: teunbrand

R/margins.R

@@ -30,6 +30,27 @@ margin_auto <- function(t = 0, r = t, b = t, l = r, unit = "pt") {
   margin(t = t, r = r, b = b, l = l, unit)
 }
 
+as_margin <- function(x, x_arg = caller_arg(x), call = caller_env()) {
+  if (is_margin(x)) {
+    return(x)
+  }
+  if (!is.unit(x)) {
+    cli::cli_abort(
+      "{.arg {x_arg}} must be a {.cls margin} class, \\
+      not {.obj_type_friendly {x}}."
+    )
+  }
+  if (length(x) != 4) {
+    x <- rep(x, length.out = 4)
+  }
+  type <- unitType(x)
+  if (is_unique(type)) {
+    type <- type[1]
+  }
+  x <- as.numeric(x)
+  margin(x[1], x[2], x[3], x[4], unit = type)
+}
+
 #' Create a text grob with the proper location and margins
 #'
 #' `titleGrob()` is called when creating titles and labels for axes, legends,

R/theme-elements.R

@@ -236,6 +236,13 @@ element_text <- S7::new_class(
         "i" = "Results may be unexpected or may change in future versions of ggplot2."
       ))
     }
+    if (!is_margin(margin) && !is.null(margin)) {
+      margin <- as_margin(margin)
+      cli::cli_warn(
+        "The {.arg margin} argument should be constructed using the \\
+        {.fn margin} function."
+      )
+    }
 
     colour <- color %||% colour
     obj <- S7::new_object(

tests/testthat/_snaps/theme.md

@@ -78,6 +78,23 @@
 
     Ignoring unknown `theme()` elements: foo and bar.
 
+# element_text throws appropriate conditions
+
+    Vectorized input to `element_text()` is not officially supported.
+    i Results may be unexpected or may change in future versions of ggplot2.
+
+---
+
+    The `margin` argument should be constructed using the `margin()` function.
+
+---
+
+    Code
+      element_text(margin = 5)
+    Condition
+      Error in `as_margin()`:
+      ! `margin` must be a <margin> class, not a number.
+
 # Theme validation behaves as expected
 
     The `aspect.ratio` theme element must be a <numeric/integer> object.

tests/testthat/test-theme.R

@@ -546,6 +546,19 @@ test_that("subtheme functions rename arguments as intended", {
   )
 })
 
+test_that("element_text throws appropriate conditions", {
+  expect_snapshot_warning(
+    element_text(colour = c("red", "blue"))
+  )
+  expect_snapshot_warning(
+    element_text(margin = unit(1, "cm"))
+  )
+  expect_snapshot(
+    element_text(margin = 5),
+    error = TRUE
+  )
+})
+
 test_that("Theme validation behaves as expected", {
   tree <- get_element_tree()
   expect_silent(check_element(1,  "aspect.ratio", tree))