From 3e97bd9aefb329ebc00e7d3deb823f4426136411 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <49372158+teunbrand@users.noreply.github.com>
Date: Wed, 20 Sep 2023 15:55:52 +0200
Subject: [PATCH 1/8] coords append information to layout

---
 R/coord-.R     | 2 ++
 R/coord-flip.R | 1 +
 2 files changed, 3 insertions(+)

diff --git a/R/coord-.R b/R/coord-.R
index 8944c812ee..154e8331f1 100644
--- a/R/coord-.R
+++ b/R/coord-.R
@@ -191,6 +191,8 @@ Coord <- ggproto("Coord",
   },
 
   setup_layout = function(layout, params) {
+    scales <- layout[c("SCALE_X", "SCALE_Y")]
+    layout$COORD <- vec_match(scales, unique0(scales))
     layout
   },
 
diff --git a/R/coord-flip.R b/R/coord-flip.R
index 1f3848fb8a..cef43b3ee1 100644
--- a/R/coord-flip.R
+++ b/R/coord-flip.R
@@ -86,6 +86,7 @@ CoordFlip <- ggproto("CoordFlip", CoordCartesian,
   },
 
   setup_layout = function(layout, params) {
+    layout <- Coord$setup_layout(layout, params)
     # Switch the scales
     layout[c("SCALE_X", "SCALE_Y")] <- layout[c("SCALE_Y", "SCALE_X")]
     layout

From ec21dc3667e25d06597f0ac295248686d903a49e Mon Sep 17 00:00:00 2001
From: Teun van den Brand <49372158+teunbrand@users.noreply.github.com>
Date: Wed, 20 Sep 2023 16:45:51 +0200
Subject: [PATCH 2/8] compute panel params/guides once per scale combination

---
 R/layout.R | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/R/layout.R b/R/layout.R
index 6e2124e8be..8f4d75537c 100644
--- a/R/layout.R
+++ b/R/layout.R
@@ -209,20 +209,27 @@ Layout <- ggproto("Layout", NULL,
     # scales is not elegant, but it is pragmatic
     self$coord$modify_scales(self$panel_scales_x, self$panel_scales_y)
 
-    scales_x <- self$panel_scales_x[self$layout$SCALE_X]
-    scales_y <- self$panel_scales_y[self$layout$SCALE_Y]
+    index <- vec_unique_loc(self$layout$COORD)
+    order <- vec_match(self$layout$COORD, self$layout$COORD[index])
+
+    scales_x <- self$panel_scales_x[self$layout$SCALE_X[index]]
+    scales_y <- self$panel_scales_y[self$layout$SCALE_Y[index]]
 
     setup_panel_params <- function(scale_x, scale_y) {
       self$coord$setup_panel_params(scale_x, scale_y, params = self$coord_params)
     }
-    self$panel_params <- Map(setup_panel_params, scales_x, scales_y)
+    self$panel_params <- Map(setup_panel_params, scales_x, scales_y)[order]
 
     invisible()
   },
 
   setup_panel_guides = function(self, guides, layers) {
+
+    index <- vec_unique_loc(self$layout$COORD)
+    order <- vec_match(self$layout$COORD, self$layout$COORD[index])
+
     self$panel_params <- lapply(
-      self$panel_params,
+      self$panel_params[index],
       self$coord$setup_panel_guides,
       guides,
       self$coord_params
@@ -233,7 +240,7 @@ Layout <- ggproto("Layout", NULL,
       self$coord$train_panel_guides,
       layers,
       self$coord_params
-    )
+    )[order]
 
     invisible()
   },

From b0dec256cc688403b73e954884f717417cc8ba76 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <49372158+teunbrand@users.noreply.github.com>
Date: Thu, 21 Sep 2023 09:26:20 +0200
Subject: [PATCH 3/8] Facets render axes once per x/y combination

---
 R/facet-grid-.R | 15 ++++++++++++++-
 R/facet-wrap.R  | 10 +++++++++-
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/R/facet-grid-.R b/R/facet-grid-.R
index 3fa73f98f3..09ad3a815b 100644
--- a/R/facet-grid-.R
+++ b/R/facet-grid-.R
@@ -306,9 +306,22 @@ FacetGrid <- ggproto("FacetGrid", Facet,
       cli::cli_abort("{.fn {snake_class(coord)}} doesn't support free scales")
     }
 
+    # Because within a row or column the scales are static, we only need to
+    # render one set of axes per row/column. If scales are fixed, we only need
+    # to render one set of axes, that we can repeat for other panels.
     cols <- which(layout$ROW == 1)
     rows <- which(layout$COL == 1)
-    axes <- render_axes(ranges[cols], ranges[rows], coord, theme, transpose = TRUE)
+    # Figure out unique x/y scale combinations
+    col_idx <- cols[!duplicated(layout$COORD[cols])]
+    row_idx <- rows[!duplicated(layout$COORD[rows])]
+    # Map all combinations to unique ones
+    col_ord <- vec_match(layout$COORD[cols], layout$COORD[col_idx])
+    row_ord <- vec_match(layout$COORD[rows], layout$COORD[row_idx])
+    # Render the axes for unique combinations
+    axes <- render_axes(ranges[col_idx], ranges[row_idx], coord, theme, transpose = TRUE)
+    # Repeat axes for all combinations
+    axes$x <- lapply(axes$x, `[`, i = col_ord)
+    axes$y <- lapply(axes$y, `[`, i = row_ord)
 
     col_vars <- unique0(layout[names(params$cols)])
     row_vars <- unique0(layout[names(params$rows)])
diff --git a/R/facet-wrap.R b/R/facet-wrap.R
index b7c19a05f3..38f6b4ffcb 100644
--- a/R/facet-wrap.R
+++ b/R/facet-wrap.R
@@ -241,7 +241,15 @@ FacetWrap <- ggproto("FacetWrap", Facet,
     panels <- panels[panel_order]
     panel_pos <- convertInd(layout$ROW, layout$COL, nrow)
 
-    axes <- render_axes(ranges, ranges, coord, theme, transpose = TRUE)
+    # If scales are fixed, we only need to render one set of axes which can be
+    # repeated. Below, we find the unique combinations of scales, and map all
+    # combinations to the unique ones.
+    index <- vec_unique_loc(layout$COORD)
+    order <- vec_match(layout$COORD, layout$COORD[index])
+
+    # Render axes and repeat them for all combinations
+    axes <- render_axes(ranges[index], ranges[index], coord, theme, transpose = TRUE)
+    axes <- lapply(axes, lapply, function(x) x[order])
 
     if (length(params$facets) == 0) {
       # Add a dummy label

From b819fa90c3dcf09fc21ba9951ed9c306176f7cf1 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <49372158+teunbrand@users.noreply.github.com>
Date: Thu, 21 Sep 2023 09:35:31 +0200
Subject: [PATCH 4/8] anonymous function to `MoreArgs`

---
 R/layout.R | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/R/layout.R b/R/layout.R
index 8f4d75537c..245630653f 100644
--- a/R/layout.R
+++ b/R/layout.R
@@ -215,10 +215,11 @@ Layout <- ggproto("Layout", NULL,
     scales_x <- self$panel_scales_x[self$layout$SCALE_X[index]]
     scales_y <- self$panel_scales_y[self$layout$SCALE_Y[index]]
 
-    setup_panel_params <- function(scale_x, scale_y) {
-      self$coord$setup_panel_params(scale_x, scale_y, params = self$coord_params)
-    }
-    self$panel_params <- Map(setup_panel_params, scales_x, scales_y)[order]
+    self$panel_params <- Map(
+      self$coord$setup_panel_params,
+      scales_x, scales_y,
+      MoreArgs = list(params = self$coord_params)
+    )[order]
 
     invisible()
   },

From c33512fce69edcf6781dcd67cea00eebea506795 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <49372158+teunbrand@users.noreply.github.com>
Date: Thu, 21 Sep 2023 09:49:25 +0200
Subject: [PATCH 5/8] Sprinkle some comments

---
 R/coord-.R | 3 +++
 R/layout.R | 6 +++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/R/coord-.R b/R/coord-.R
index 154e8331f1..d83b501cb5 100644
--- a/R/coord-.R
+++ b/R/coord-.R
@@ -191,6 +191,9 @@ Coord <- ggproto("Coord",
   },
 
   setup_layout = function(layout, params) {
+    # We're appending a COORD variable to the layout that determines the
+    # uniqueness of panel parameters. The layout uses this to prevent redundant
+    # setups of these parameters.
     scales <- layout[c("SCALE_X", "SCALE_Y")]
     layout$COORD <- vec_match(scales, unique0(scales))
     layout
diff --git a/R/layout.R b/R/layout.R
index 245630653f..8661d60e67 100644
--- a/R/layout.R
+++ b/R/layout.R
@@ -209,6 +209,8 @@ Layout <- ggproto("Layout", NULL,
     # scales is not elegant, but it is pragmatic
     self$coord$modify_scales(self$panel_scales_x, self$panel_scales_y)
 
+    # We only need to setup panel params once for unique combinations of x/y
+    # scales. These will be repeated for duplicated combinations.
     index <- vec_unique_loc(self$layout$COORD)
     order <- vec_match(self$layout$COORD, self$layout$COORD[index])
 
@@ -219,13 +221,15 @@ Layout <- ggproto("Layout", NULL,
       self$coord$setup_panel_params,
       scales_x, scales_y,
       MoreArgs = list(params = self$coord_params)
-    )[order]
+    )[order] # `[order]` does the repeating
 
     invisible()
   },
 
   setup_panel_guides = function(self, guides, layers) {
 
+    # Like in `setup_panel_params`, we only need to setup guides for unique
+    # combinations of x/y scales.
     index <- vec_unique_loc(self$layout$COORD)
     order <- vec_match(self$layout$COORD, self$layout$COORD[index])
 

From 28b334179508a5505dbebfec4880845499f73fce Mon Sep 17 00:00:00 2001
From: Teun van den Brand <49372158+teunbrand@users.noreply.github.com>
Date: Thu, 21 Sep 2023 09:52:09 +0200
Subject: [PATCH 6/8] Add news bullet

---
 NEWS.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/NEWS.md b/NEWS.md
index 5b4d074c57..ee5a22ebef 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,8 @@
 # ggplot2 (development version)
 
+* (internal) The plot's layout now has a coord parameters that is used to 
+  prevent setting up identical panel parameters (#5427)
+
 * `ScaleContinuous$get_breaks()` now only calls `scales::zero_range()` on limits
   in transformed space, rather than in data space (#5304).
 

From 88b61562206da1a5b49fcae102b5e51100c80731 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <49372158+teunbrand@users.noreply.github.com>
Date: Thu, 21 Sep 2023 09:56:10 +0200
Subject: [PATCH 7/8] add test

---
 tests/testthat/test-coord-.R | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/tests/testthat/test-coord-.R b/tests/testthat/test-coord-.R
index ca7f62c06e..b372478981 100644
--- a/tests/testthat/test-coord-.R
+++ b/tests/testthat/test-coord-.R
@@ -53,3 +53,26 @@ test_that("check coord limits errors only on bad inputs", {
   # Should raise error if vector of wrong length is passed
   expect_error(check_coord_limits(1:3))
 })
+
+test_that("coords append a column to the layout correctly", {
+  layout <- data_frame0(SCALE_X = c(1, 1, 1), SCALE_Y = c(1, 1, 1))
+  test <- Coord$setup_layout(layout)
+  expect_equal(test$COORD, c(1, 1, 1))
+
+  layout <- data_frame0(SCALE_X = c(1, 1, 1), SCALE_Y = c(1, 2, 2))
+  test <- Coord$setup_layout(layout)
+  expect_equal(test$COORD, c(1, 2, 2))
+
+  layout <- data_frame0(SCALE_X = c(1, 2, 3), SCALE_Y = c(1, 1, 1))
+  test <- Coord$setup_layout(layout)
+  expect_equal(test$COORD, c(1, 2, 3))
+
+  layout <- data_frame0(SCALE_X = c(1, 2, 3), SCALE_Y = c(1, 2, 3))
+  test <- Coord$setup_layout(layout)
+  expect_equal(test$COORD, c(1, 2, 3))
+
+  layout <- data_frame0(SCALE_X = c(1, 1, 1), SCALE_Y = c(1, 2, 1))
+  test <- Coord$setup_layout(layout)
+  expect_equal(test$COORD, c(1, 2, 1))
+})
+

From 41cfd5fe12373542aff134b6009144d9084a7a77 Mon Sep 17 00:00:00 2001
From: Teun van den Brand <tahvdbrand@gmail.com>
Date: Mon, 20 May 2024 14:08:34 +0200
Subject: [PATCH 8/8] format bullet

---
 NEWS.md | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index bb9ed2ee44..01d225cf97 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -2,9 +2,6 @@
 
 * (internal) The plot's layout now has a coord parameters that is used to 
   prevent setting up identical panel parameters (#5427)
-
-* Legend titles no longer take up space if they've been removed by setting 
-  `legend.title = element_blank()` (@teunbrand, #3587).
 * Discrete position scales now expose the `palette` argument, which can be used 
   to customise spacings between levels (@teunbrand, #5770).
 * The default `se` parameter in layers with `geom = "smooth"` will be `TRUE`