From c2229c1829233860886502b18473ea7f15186da6 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Fri, 31 May 2024 14:16:13 +0200
Subject: [PATCH 1/7] `reverse` plumbing for `position_dodge()

---
 R/position-dodge.R | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/R/position-dodge.R b/R/position-dodge.R
index 17bd607324..4baf10ad27 100644
--- a/R/position-dodge.R
+++ b/R/position-dodge.R
@@ -82,11 +82,14 @@
 #'
 #' ggplot(mtcars, aes(factor(cyl), fill = factor(vs))) +
 #'   geom_bar(position = position_dodge2(preserve = "total"))
-position_dodge <- function(width = NULL, preserve = "total", orientation = "x") {
+position_dodge <- function(width = NULL, preserve = "total", orientation = "x",
+                           reverse = TRUE) {
+  check_bool(reverse)
   ggproto(NULL, PositionDodge,
     width = width,
     preserve = arg_match0(preserve, c("total", "single")),
-    orientation = arg_match0(orientation, c("x", "y"))
+    orientation = arg_match0(orientation, c("x", "y")),
+    reverse = reverse
   )
 }
 
@@ -98,6 +101,7 @@ PositionDodge <- ggproto("PositionDodge", Position,
   width = NULL,
   preserve = "total",
   orientation = "x",
+  reverse = NULL,
   setup_params = function(self, data) {
     flipped_aes <- has_flipped_aes(data, default = self$orientation == "y")
     data <- flip_data(data, flipped_aes)
@@ -119,7 +123,8 @@ PositionDodge <- ggproto("PositionDodge", Position,
     list(
       width = self$width,
       n = n,
-      flipped_aes = flipped_aes
+      flipped_aes = flipped_aes,
+      reverse = self$reverse %||% TRUE
     )
   },
 
@@ -139,7 +144,8 @@ PositionDodge <- ggproto("PositionDodge", Position,
       name = "position_dodge",
       strategy = pos_dodge,
       n = params$n,
-      check.width = FALSE
+      check.width = FALSE,
+      reverse = params$reverse
     )
     flip_data(collided, params$flipped_aes)
   }

From e0976b34f35b6ad78fd3dc7a396723d3fcccb740 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Fri, 31 May 2024 14:16:27 +0200
Subject: [PATCH 2/7] `reverse` plumbing in `position_jitterdodge()`

---
 R/position-jitterdodge.R | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/R/position-jitterdodge.R b/R/position-jitterdodge.R
index fba28a47fa..1f9b4a7192 100644
--- a/R/position-jitterdodge.R
+++ b/R/position-jitterdodge.R
@@ -11,6 +11,7 @@
 #' @param dodge.width the amount to dodge in the x direction. Defaults to 0.75,
 #'   the default `position_dodge()` width.
 #' @inheritParams position_jitter
+#' @inheritParams position_dodge
 #' @export
 #' @examples
 #' set.seed(596)
@@ -19,15 +20,18 @@
 #'   geom_boxplot(outlier.size = 0) +
 #'   geom_point(pch = 21, position = position_jitterdodge())
 position_jitterdodge <- function(jitter.width = NULL, jitter.height = 0,
-                                 dodge.width = 0.75, seed = NA) {
+                                 dodge.width = 0.75, reverse = TRUE,
+                                 seed = NA) {
   if (!is.null(seed) && is.na(seed)) {
     seed <- sample.int(.Machine$integer.max, 1L)
   }
+  check_bool(reverse)
 
   ggproto(NULL, PositionJitterdodge,
     jitter.width = jitter.width,
     jitter.height = jitter.height,
     dodge.width = dodge.width,
+    reverse = reverse,
     seed = seed
   )
 }
@@ -40,6 +44,7 @@ PositionJitterdodge <- ggproto("PositionJitterdodge", Position,
   jitter.width = NULL,
   jitter.height = NULL,
   dodge.width = NULL,
+  reverse = NULL,
 
   required_aes = c("x", "y"),
 
@@ -64,14 +69,15 @@ PositionJitterdodge <- ggproto("PositionJitterdodge", Position,
       jitter.height = self$jitter.height,
       jitter.width = width / (ndodge + 2),
       seed = self$seed,
-      flipped_aes = flipped_aes
+      flipped_aes = flipped_aes,
+      reverse = self$reverse %||% TRUE
     )
   },
 
   compute_panel = function(data, params, scales) {
     data <- flip_data(data, params$flipped_aes)
     data <- collide(data, params$dodge.width, "position_jitterdodge", pos_dodge,
-      check.width = FALSE)
+                    check.width = FALSE, reverse = params$reverse)
 
     trans_x <- if (params$jitter.width > 0) function(x) jitter(x, amount = params$jitter.width)
     trans_y <- if (params$jitter.height > 0) function(x) jitter(x, amount = params$jitter.height)

From 6e61a363836fef9fdc9da30240142dfa44a596e9 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Fri, 31 May 2024 14:16:57 +0200
Subject: [PATCH 3/7] do not internally sort groups in `position_dodge()`

---
 R/position-dodge.R | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/R/position-dodge.R b/R/position-dodge.R
index 4baf10ad27..7b28b2e6bd 100644
--- a/R/position-dodge.R
+++ b/R/position-dodge.R
@@ -170,7 +170,7 @@ pos_dodge <- function(df, width, n = NULL) {
 
   # Have a new group index from 1 to number of groups.
   # This might be needed if the group numbers in this set don't include all of 1:n
-  groupidx <- match(df$group, sort(unique0(df$group)))
+  groupidx <- match(df$group, unique0(df$group))
 
   # Find the center for each group, then use that to calculate xmin and xmax
   df$x <- df$x + width * ((groupidx - 0.5) / n - .5)

From ea5d9dab82421830f309ee4c7e1029abe3066791 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Fri, 31 May 2024 14:24:09 +0200
Subject: [PATCH 4/7] add test

---
 tests/testthat/test-position_dodge.R | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/tests/testthat/test-position_dodge.R b/tests/testthat/test-position_dodge.R
index 51d7b54cce..4aa66afb71 100644
--- a/tests/testthat/test-position_dodge.R
+++ b/tests/testthat/test-position_dodge.R
@@ -23,3 +23,17 @@ test_that("position_dodge() can dodge points vertically", {
   expect_equal(layer_data(vertical)$y,   c(0.75, 1.25, 1.75, 2.25), ignore_attr = "class")
 
 })
+
+test_that("position_dodge() can reverse the dodge order", {
+
+  df <- data.frame(x = c(1, 2, 2, 3, 3), group = c("A", "A", "B", "B", "C"))
+
+  # Use label as easy to track identifier
+  p <- ggplot(df, aes(x, y = 1, fill = group, label = group))
+
+  ld <- get_layer_data(p + geom_col(position = position_dodge(reverse = FALSE)))
+  expect_equal(ld$label[order(ld$x)], c("A", "B", "A", "C", "B"))
+
+  ld <- get_layer_data(p + geom_col(position = position_dodge(reverse = TRUE)))
+  expect_equal(ld$label[order(ld$x)], c("A", "A", "B", "B", "C"))
+})

From 93f88b02f5e5fc560ada339baa9a64afe8974aac Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Fri, 31 May 2024 14:24:53 +0200
Subject: [PATCH 5/7] add news bullet

---
 NEWS.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/NEWS.md b/NEWS.md
index de3e87cee3..ee368aea40 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,7 @@
 # ggplot2 (development version)
 
+* `position_dodge()` and `position_jitterdodge()` now have a `reverse` argument 
+  (@teunbrand, #3610)
 * The `arrow.fill` parameter is now applied to more line-based functions: 
   `geom_path()`, `geom_line()`, `geom_step()` `geom_function()`, line 
    geometries in `geom_sf()` and `element_line()`.

From 01243456b2ffa86d58e0c7a85e1942510e56ac72 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Fri, 31 May 2024 14:38:56 +0200
Subject: [PATCH 6/7] Align interpretation with `position_dodge2()`

---
 R/position-dodge.R                   |  6 +++---
 R/position-jitterdodge.R             | 14 ++++++++++----
 tests/testthat/test-position_dodge.R |  4 ++--
 3 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/R/position-dodge.R b/R/position-dodge.R
index 7b28b2e6bd..84578c6b5d 100644
--- a/R/position-dodge.R
+++ b/R/position-dodge.R
@@ -83,7 +83,7 @@
 #' ggplot(mtcars, aes(factor(cyl), fill = factor(vs))) +
 #'   geom_bar(position = position_dodge2(preserve = "total"))
 position_dodge <- function(width = NULL, preserve = "total", orientation = "x",
-                           reverse = TRUE) {
+                           reverse = FALSE) {
   check_bool(reverse)
   ggproto(NULL, PositionDodge,
     width = width,
@@ -124,7 +124,7 @@ PositionDodge <- ggproto("PositionDodge", Position,
       width = self$width,
       n = n,
       flipped_aes = flipped_aes,
-      reverse = self$reverse %||% TRUE
+      reverse = self$reverse %||% FALSE
     )
   },
 
@@ -145,7 +145,7 @@ PositionDodge <- ggproto("PositionDodge", Position,
       strategy = pos_dodge,
       n = params$n,
       check.width = FALSE,
-      reverse = params$reverse
+      reverse = !params$reverse # for consistency with `position_dodge2()`
     )
     flip_data(collided, params$flipped_aes)
   }
diff --git a/R/position-jitterdodge.R b/R/position-jitterdodge.R
index 1f9b4a7192..2641cdd443 100644
--- a/R/position-jitterdodge.R
+++ b/R/position-jitterdodge.R
@@ -20,7 +20,7 @@
 #'   geom_boxplot(outlier.size = 0) +
 #'   geom_point(pch = 21, position = position_jitterdodge())
 position_jitterdodge <- function(jitter.width = NULL, jitter.height = 0,
-                                 dodge.width = 0.75, reverse = TRUE,
+                                 dodge.width = 0.75, reverse = FALSE,
                                  seed = NA) {
   if (!is.null(seed) && is.na(seed)) {
     seed <- sample.int(.Machine$integer.max, 1L)
@@ -70,14 +70,20 @@ PositionJitterdodge <- ggproto("PositionJitterdodge", Position,
       jitter.width = width / (ndodge + 2),
       seed = self$seed,
       flipped_aes = flipped_aes,
-      reverse = self$reverse %||% TRUE
+      reverse = self$reverse %||% FALSE
     )
   },
 
   compute_panel = function(data, params, scales) {
     data <- flip_data(data, params$flipped_aes)
-    data <- collide(data, params$dodge.width, "position_jitterdodge", pos_dodge,
-                    check.width = FALSE, reverse = params$reverse)
+    data <- collide(
+      data,
+      params$dodge.width,
+      "position_jitterdodge",
+      strategy = pos_dodge,
+      check.width = FALSE,
+      reverse = !params$reverse # for consistency with `position_dodge2()`
+    )
 
     trans_x <- if (params$jitter.width > 0) function(x) jitter(x, amount = params$jitter.width)
     trans_y <- if (params$jitter.height > 0) function(x) jitter(x, amount = params$jitter.height)
diff --git a/tests/testthat/test-position_dodge.R b/tests/testthat/test-position_dodge.R
index 4aa66afb71..1d7127a239 100644
--- a/tests/testthat/test-position_dodge.R
+++ b/tests/testthat/test-position_dodge.R
@@ -31,9 +31,9 @@ test_that("position_dodge() can reverse the dodge order", {
   # Use label as easy to track identifier
   p <- ggplot(df, aes(x, y = 1, fill = group, label = group))
 
-  ld <- get_layer_data(p + geom_col(position = position_dodge(reverse = FALSE)))
+  ld <- get_layer_data(p + geom_col(position = position_dodge(reverse = TRUE)))
   expect_equal(ld$label[order(ld$x)], c("A", "B", "A", "C", "B"))
 
-  ld <- get_layer_data(p + geom_col(position = position_dodge(reverse = TRUE)))
+  ld <- get_layer_data(p + geom_col(position = position_dodge(reverse = FALSE)))
   expect_equal(ld$label[order(ld$x)], c("A", "A", "B", "B", "C"))
 })

From 05de68b07c4f848545cff13578aabb77dbe4c3e1 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Fri, 31 May 2024 15:06:05 +0200
Subject: [PATCH 7/7] document

---
 R/position-dodge.R          |  2 ++
 R/position-dodge2.R         |  2 --
 man/position_dodge.Rd       | 13 +++++++++----
 man/position_jitterdodge.Rd |  4 ++++
 4 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/R/position-dodge.R b/R/position-dodge.R
index 84578c6b5d..4fcee78d70 100644
--- a/R/position-dodge.R
+++ b/R/position-dodge.R
@@ -16,6 +16,8 @@
 #' @param orientation Fallback orientation when the layer or the data does not
 #'    indicate an explicit orientation, like `geom_point()`. Can be `"x"`
 #'    (default) or `"y"`.
+#' @param reverse If `TRUE`, will reverse the default stacking order.
+#'   This is useful if you're rotating both the plot and legend.
 #' @family position adjustments
 #' @export
 #' @examples
diff --git a/R/position-dodge2.R b/R/position-dodge2.R
index a4c5fdc8ba..bf5f18c56d 100644
--- a/R/position-dodge2.R
+++ b/R/position-dodge2.R
@@ -2,8 +2,6 @@
 #' @rdname position_dodge
 #' @param padding Padding between elements at the same position. Elements are
 #'   shrunk by this proportion to allow space between them. Defaults to 0.1.
-#' @param reverse If `TRUE`, will reverse the default stacking order.
-#'   This is useful if you're rotating both the plot and legend.
 position_dodge2 <- function(width = NULL, preserve = "total",
                             padding = 0.1, reverse = FALSE) {
   ggproto(NULL, PositionDodge2,
diff --git a/man/position_dodge.Rd b/man/position_dodge.Rd
index 3efb462168..e4f9211110 100644
--- a/man/position_dodge.Rd
+++ b/man/position_dodge.Rd
@@ -5,7 +5,12 @@
 \alias{position_dodge2}
 \title{Dodge overlapping objects side-to-side}
 \usage{
-position_dodge(width = NULL, preserve = "total", orientation = "x")
+position_dodge(
+  width = NULL,
+  preserve = "total",
+  orientation = "x",
+  reverse = FALSE
+)
 
 position_dodge2(
   width = NULL,
@@ -26,11 +31,11 @@ at a position, or the width of a \code{"single"} element?}
 indicate an explicit orientation, like \code{geom_point()}. Can be \code{"x"}
 (default) or \code{"y"}.}
 
-\item{padding}{Padding between elements at the same position. Elements are
-shrunk by this proportion to allow space between them. Defaults to 0.1.}
-
 \item{reverse}{If \code{TRUE}, will reverse the default stacking order.
 This is useful if you're rotating both the plot and legend.}
+
+\item{padding}{Padding between elements at the same position. Elements are
+shrunk by this proportion to allow space between them. Defaults to 0.1.}
 }
 \description{
 Dodging preserves the vertical position of an geom while adjusting the
diff --git a/man/position_jitterdodge.Rd b/man/position_jitterdodge.Rd
index d158162211..ca5bb8e30c 100644
--- a/man/position_jitterdodge.Rd
+++ b/man/position_jitterdodge.Rd
@@ -8,6 +8,7 @@ position_jitterdodge(
   jitter.width = NULL,
   jitter.height = 0,
   dodge.width = 0.75,
+  reverse = FALSE,
   seed = NA
 )
 }
@@ -20,6 +21,9 @@ resolution of the data.}
 \item{dodge.width}{the amount to dodge in the x direction. Defaults to 0.75,
 the default \code{position_dodge()} width.}
 
+\item{reverse}{If \code{TRUE}, will reverse the default stacking order.
+This is useful if you're rotating both the plot and legend.}
+
 \item{seed}{A random seed to make the jitter reproducible.
 Useful if you need to apply the same jitter twice, e.g., for a point and
 a corresponding label.