Support empty plots (type = "n")

NEWS.md

@@ -6,6 +6,14 @@ where the formatting is also better._
 
 ## 0.1.0.99 (dev version)
 
+New features:
+
+- Support for `type = "n"` (empty) plots. (#157 @grantmcdermott)
+
+Misc:
+
+- Various documentation improvements.
+
 ## 0.1.0
 
 Our first CRAN submission! This v0.1.0 release includes the following new

R/draw_legend.R

@@ -175,6 +175,9 @@ draw_legend = function(
     if (is.null(legend_args[["y.intersp"]])) legend_args[["y.intersp"]] = 1.25
     if (is.null(legend_args[["seg.len"]])) legend_args[["seg.len"]] = 1.25
   }
+  if (type == "n" && isFALSE(gradient)) {
+    if (is.null(legend_args[["pch"]])) legend_args[["pch"]] = par("pch")
+  }
 
 
   if (is.null(legend_args[["legend"]])) {

R/tinyplot.R

@@ -70,9 +70,9 @@
 #' @param type character string giving the type of plot desired. Options are:
 #'   - The same set of 1-character values supported by plot: "p" for points, "l"
 #'   for lines, "b" for both points and lines, "c" for empty points joined by
-#'   lines, "o" for overplotted points and lines, "s" and "S" for stair steps
-#'   and "h" for histogram-like vertical lines. "n" does not produce
-#'   any points or lines.
+#'   lines, "o" for overplotted points and lines, "s" and "S" for stair steps,
+#'   and "h" for histogram-like vertical lines. Specifying "n" produces an empty
+#'   plot over the extent of the data, but with no internal elements.
 #'   - Additional tinyplot types: "density" for densities, "polygon" for
 #'   polygons,  "pointrange" or "errorbar" for segment intervals, and "polygon",
 #'   "ribbon" or "area" for polygon intervals (where area plots are a special
@@ -1372,6 +1372,8 @@ tinyplot.default = function(
           lty = ilty,
           lwd = ilwd
         )
+      } else if (type == "n") {
+        # Blank plot
       } else {
         stop("`type` argument not supported.", call. = FALSE)
       }

inst/tinytest/test-misc.R

@@ -1,6 +1,18 @@
 source("helpers.R")
 using("tinysnapshot")
 
+# empty plot(s)
+f = function () {
+  tinyplot(Sepal.Length ~ Petal.Length, data = iris, type = "n")
+}
+expect_snapshot_plot(f, label = "type_n")
+# empty plot(s)
+f = function () {
+  tinyplot(Sepal.Length ~ Petal.Length | Species, data = iris, type = "n")
+}
+expect_snapshot_plot(f, label = "type_n_by")
+
+# log axes
 f = function() {
   op = tpar(mfrow = c(1, 2))
   plot(Temp ~ Day, data = airquality, log = "x")
@@ -33,9 +45,6 @@ f = function() {
 } 
 expect_snapshot_plot(f, label = "arg_log_yx")
 
-## https://bugs.r-project.org/show_bug.cgi?id=18337
-# exit_if_not(getRversion() >= "4.4.0")
-
 f = function() {
   op = tpar(mfrow = c(1, 1))
   m = transform(mtcars, cyl = factor(cyl))