Support width and height aesthetics in geom_tile

Thanks to @malcolmbarrett. Closes #2510

Author: hadley

NEWS.md

@@ -244,6 +244,9 @@ up correct aspect ratio, and draws a graticule.
   to pass pre-computed values without manual ordering (@izahn, #2028).
   It also now knows it has `ymin` and `ymax` aesthetics (#1939).
 
+* `geom_tile()` now once again interprets `width` and `height` correctly 
+  (@malcolmbarrett, #2510)
+
 * `position_dodge()` gains an `preserve` argument that allows you to control
   whether the `total` width at each `x` value is preserved (the current 
   default), or ensure that the width of a `single` element is preserved

R/geom-tile.r

@@ -30,7 +30,7 @@
 #'   w = rep(diff(c(0, 4, 6, 8, 10, 14)), 2)
 #' )
 #' ggplot(df, aes(x, y)) +
-#'   geom_tile(aes(fill = z))
+#'   geom_tile(aes(fill = z), colour = "grey50")
 #' ggplot(df, aes(x, y)) +
 #'   geom_tile(aes(fill = z, width = w), colour = "grey50")
 #' ggplot(df, aes(xmin = x - w / 2, xmax = x + w / 2, ymin = y, ymax = y + 1)) +
@@ -81,7 +81,7 @@ geom_tile <- function(mapping = NULL, data = NULL,
 #' @export
 #' @include geom-rect.r
 GeomTile <- ggproto("GeomTile", GeomRect,
-  extra_params = c("na.rm", "width", "height"),
+  extra_params = c("na.rm"),
 
   setup_data = function(data, params) {
     data$width <- data$width %||% params$width %||% resolution(data$x, FALSE)
@@ -94,7 +94,7 @@ GeomTile <- ggproto("GeomTile", GeomRect,
   },
 
   default_aes = aes(fill = "grey20", colour = NA, size = 0.1, linetype = 1,
-    alpha = NA),
+    alpha = NA, width = NA, height = NA),
 
   required_aes = c("x", "y"),
 

man/geom_tile.Rd

@@ -11,3 +11,18 @@ test_that("accepts width and height params", {
   expect_equal(out2$xmin, c(0.75, 1.75))
   expect_equal(out2$xmax, c(1.25, 2.25))
 })
+
+test_that("accepts width and height aesthetics", {
+  df <- data.frame(x = 0, y = 0, width = c(2, 4), height = c(2, 4))
+
+  p <- ggplot(df, aes(x, y, width = width, height = height)) +
+    geom_tile(fill = NA, colour = "black", size = 1)
+  out <- layer_data(p)
+
+  boundary <- as.data.frame(tibble::tribble(
+    ~xmin, ~xmax, ~ymin, ~ymax,
+       -1,    1,     -1,    1,
+       -2,    2,     -2,    2
+  ))
+  expect_equal(out[c("xmin", "xmax", "ymin", "ymax")], boundary)
+})