Legend: support title = FALSE

NEWS.md

@@ -265,6 +265,8 @@ Theme fixes:
   - Model-fit and various distribution types gain a `weights` argument; although
     this is best provided from the top-level `tinyplot()`/`plt()` call. See
     above.
+- `legend = list(title = FALSE)` now suppresses the legend title, matching the
+  existing `title = NULL` behaviour. (#653 @grantmcdermott)
 
 ### Bug fixes
 

R/legend.R

@@ -574,6 +574,8 @@ build_legend_args = function(
 
   # Set defaults
   if (!exists("title", where = legend_args)) legend_args[["title"]] = by_dep
+  # Treat title = FALSE the same as NULL, i.e. suppress the title (#652).
+  if (isFALSE(legend_args[["title"]])) legend_args[["title"]] = NULL
   legend_args[["pch"]] = legend_args[["pch"]] %||% pch
   legend_args[["lty"]] = legend_args[["lty"]] %||% lty
   legend_args[["col"]] = legend_args[["col"]] %||% col

R/tinyplot.R

@@ -166,7 +166,9 @@
 #'    effect as specifying NULL) and FALSE turns the legend off (same effect as
 #'    specifying "none").
 #'    - A list or, equivalently, a dedicated `legend()` function with supported
-#'    legend arguments, e.g. "bty", "horiz", and so forth.
+#'    legend arguments, e.g. "bty", "horiz", and so forth. To suppress the
+#'    legend title, set `title = NULL` or `title = FALSE`, e.g.
+#'    `legend = list(title = FALSE)`.
 #' @param main a main title for the plot, see also `title`.
 #' @param sub a subtitle for the plot.
 #' @param cap a caption for the plot, drawn at the bottom. Useful for

inst/tinytest/test-legend.R

@@ -124,6 +124,13 @@ f = function() tinyplot(
 )
 expect_snapshot_plot(f, label = "legend_title_null")
 
+# title = FALSE should suppress the title, just like title = NULL (#652)
+f = function() tinyplot(
+  Temp ~ Day | Month, data = aq,
+  legend = list(title = FALSE)
+)
+expect_snapshot_plot(f, label = "legend_title_null")
+
 f = function() tinyplot(
   Temp ~ Day | Month, data = aq,
   legend = legend(legend = month.abb[5:9])

vignettes/gallery_figs/ellipse-penguins.R

@@ -6,7 +6,7 @@ plt(
   main = 'A waddle of penguins',
   sub = 'Species stick together',
   theme = 'web',
-  legend = list('top!', title = NULL)
+  legend = list('top!', title = FALSE)
 )
 plt_add(type = 'ellipse', fill = 0.1)
 # plt_add(type = 'chull', fill = 0.1, col = NA) ## another option

vignettes/gallery_figs/likert.R

@@ -21,7 +21,7 @@ plt(
   share ~ question | response, data = lik,
   type = "barplot", center = TRUE, offset = "Unsure",
   flip = TRUE, xlab = NA, ylab = NA, yaxl = "percent",
-  legend = list("top!", title = NULL),
+  legend = list("top!", title = FALSE),
   theme = list("clean2", palette.qualitative = pal),
   main = "Likert example with \"Unsure\" category offset"
 )