Support size and linetype in geom_hex (#2488) (#2670)

* Support size and linetype in geom_hex (#2488)

* Add unit test for geom_hex size and linetype

* Update NEWS with new geom_hex() aesthetics

Author: mikmart

NEWS.md

@@ -1,5 +1,8 @@
 # ggplot2 3.0.0.9000
 
+* `geom_hex()` now understands the `size` and `linetype` aesthetics
+  (@mikmart, #2488).
+  
 # ggplot2 3.0.0
 
 ## Breaking changes

R/geom-hex.r

@@ -59,16 +59,27 @@ GeomHex <- ggproto("GeomHex", Geom,
       stop("geom_hex() only works with Cartesian coordinates", call. = FALSE)
     }
 
-    coord <- coord$transform(data, panel_params)
+    coords <- coord$transform(data, panel_params)
     ggname("geom_hex", hexGrob(
-      coord$x, coord$y, colour = coord$colour,
-      fill = alpha(coord$fill, coord$alpha)
+      coords$x, coords$y,
+      gp = gpar(
+        col = coords$colour,
+        fill = alpha(coords$fill, coords$alpha),
+        lwd = coords$size * .pt,
+        lty = coords$linetype
+      )
     ))
   },
 
   required_aes = c("x", "y"),
 
-  default_aes = aes(colour = NA, fill = "grey50", size = 0.5, alpha = NA),
+  default_aes = aes(
+    colour = NA,
+    fill = "grey50",
+    size = 0.5,
+    linetype = 1,
+    alpha = NA
+  ),
 
   draw_key = draw_key_polygon
 )
@@ -79,11 +90,10 @@ GeomHex <- ggproto("GeomHex", Geom,
 #
 # @param x positions of hex centres
 # @param y positions
-# @param vector of hex sizes
-# @param border colour
-# @param fill colour
+# @param size vector of hex sizes
+# @param gp graphical parameters
 # @keyword internal
-hexGrob <- function(x, y, size = rep(1, length(x)), colour = "grey50", fill = "grey90") {
+hexGrob <- function(x, y, size = rep(1, length(x)), gp = gpar()) {
   stopifnot(length(y) == length(x))
 
   dx <- resolution(x, FALSE)
@@ -97,6 +107,6 @@ hexGrob <- function(x, y, size = rep(1, length(x)), colour = "grey50", fill = "g
     x = rep.int(hexC$x, n) * rep(size, each = 6) + rep(x, each = 6),
     y = rep.int(hexC$y, n) * rep(size, each = 6) + rep(y, each = 6),
     default.units = "native",
-    id.lengths = rep(6, n), gp = gpar(col = colour, fill = fill)
+    id.lengths = rep(6, n), gp = gp
   )
 }

man/geom_hex.Rd

@@ -10,3 +10,13 @@ test_that("density and value summaries are available", {
   expect_equal(out$density, c(0.75, 0.25), tolerance = 1e-7)
   expect_equal(out$count, c(3, 1), tolerance = 1e-7)
 })
+
+test_that("size and linetype are applied", {
+  df <- data.frame(x = c(1, 1, 1, 2), y = c(1, 1, 1, 2))
+  plot <- ggplot(df, aes(x, y)) +
+    geom_hex(color = "red", size = 4, linetype = 2)
+
+  gpar <- layer_grob(plot)[[1]]$children[[1]]$gp
+  expect_equal(gpar$lwd, c(4, 4) * .pt, tolerance = 1e-7)
+  expect_equal(gpar$lty, c(2, 2), tolerance = 1e-7)
+})