check if axis is present before adding padding to facet_grid (#4669)

Author: thomasp85

NEWS.md

@@ -1,5 +1,8 @@
 # ggplot2 (development version)
 
+* Strip padding in `facet_grid()` is now only in effect if `strip.placement = "outside"`
+  _and_ an axis is present between the strip and the panel (@thomasp85, #4610)
+
 * Aesthetics of length 1 are now recycled to 0 if the length of the data is 0 
   (@thomasp85, #4588)
 

R/facet-grid-.r

@@ -356,10 +356,14 @@ FacetGrid <- ggproto("FacetGrid", Facet,
       theme$panel.spacing.y %||% theme$panel.spacing)
 
     # Add axes
-    panel_table <- gtable_add_rows(panel_table, max_height(axes$x$top), 0)
-    panel_table <- gtable_add_rows(panel_table, max_height(axes$x$bottom), -1)
-    panel_table <- gtable_add_cols(panel_table, max_width(axes$y$left), 0)
-    panel_table <- gtable_add_cols(panel_table, max_width(axes$y$right), -1)
+    axis_height_top <- max_height(axes$x$top)
+    axis_height_bottom <- max_height(axes$x$bottom)
+    axis_width_left <- max_width(axes$y$left)
+    axis_width_right <- max_width(axes$y$right)
+    panel_table <- gtable_add_rows(panel_table, axis_height_top, 0)
+    panel_table <- gtable_add_rows(panel_table, axis_height_bottom, -1)
+    panel_table <- gtable_add_cols(panel_table, axis_width_left, 0)
+    panel_table <- gtable_add_cols(panel_table, axis_width_right, -1)
     panel_pos_col <- panel_cols(panel_table)
     panel_pos_rows <- panel_rows(panel_table)
 
@@ -377,7 +381,7 @@ FacetGrid <- ggproto("FacetGrid", Facet,
     panel_pos_col <- panel_cols(panel_table)
     if (switch_x) {
       if (!is.null(strips$x$bottom)) {
-        if (inside_x) {
+        if (inside_x || as.numeric(axis_height_bottom) == 0) {
           panel_table <- gtable_add_rows(panel_table, max_height(strips$x$bottom), -2)
           panel_table <- gtable_add_grob(panel_table, strips$x$bottom, -2, panel_pos_col$l, clip = "on", name = paste0("strip-b-", seq_along(strips$x$bottom)), z = 2)
         } else {
@@ -388,7 +392,7 @@ FacetGrid <- ggproto("FacetGrid", Facet,
       }
     } else {
       if (!is.null(strips$x$top)) {
-        if (inside_x) {
+        if (inside_x || as.numeric(axis_height_top) == 0) {
           panel_table <- gtable_add_rows(panel_table, max_height(strips$x$top), 1)
           panel_table <- gtable_add_grob(panel_table, strips$x$top, 2, panel_pos_col$l, clip = "on", name = paste0("strip-t-", seq_along(strips$x$top)), z = 2)
         } else {
@@ -401,7 +405,7 @@ FacetGrid <- ggproto("FacetGrid", Facet,
     panel_pos_rows <- panel_rows(panel_table)
     if (switch_y) {
       if (!is.null(strips$y$left)) {
-        if (inside_y) {
+        if (inside_y || as.numeric(axis_width_left) == 0) {
           panel_table <- gtable_add_cols(panel_table, max_width(strips$y$left), 1)
           panel_table <- gtable_add_grob(panel_table, strips$y$left, panel_pos_rows$t, 2, clip = "on", name = paste0("strip-l-", seq_along(strips$y$left)), z = 2)
         } else {
@@ -412,7 +416,7 @@ FacetGrid <- ggproto("FacetGrid", Facet,
       }
     } else {
       if (!is.null(strips$y$right)) {
-        if (inside_y) {
+        if (inside_y || as.numeric(axis_width_right) == 0) {
           panel_table <- gtable_add_cols(panel_table, max_width(strips$y$right), -2)
           panel_table <- gtable_add_grob(panel_table, strips$y$right, panel_pos_rows$t, -2, clip = "on", name = paste0("strip-r-", seq_along(strips$y$right)), z = 2)
         } else {

tests/testthat/test-facet-strips.r

@@ -131,6 +131,32 @@ test_that("strips can be removed", {
   expect_true(all(sapply(strip_grobs, inherits, 'zeroGrob')))
 })
 
+test_that("strips can be removed", {
+  dat <- data_frame(a = rep(LETTERS[1:10], 10), x = rnorm(100), y = rnorm(100))
+  g <- ggplot(dat, aes(x = x, y = y)) +
+    geom_point() +
+    facet_wrap(~a) +
+    theme(strip.background = element_blank(), strip.text = element_blank())
+  g_grobs <- ggplotGrob(g)
+  strip_grobs <- g_grobs$grobs[grepl('strip-', g_grobs$layout$name)]
+  expect_true(all(sapply(strip_grobs, inherits, 'zeroGrob')))
+})
+
+test_that("padding is only added if axis is present", {
+  p <- ggplot(data = mpg, aes(x = displ, y = hwy)) +
+    facet_grid(. ~ drv) +
+    theme(
+      strip.placement = "outside",
+      strip.switch.pad.grid = unit(10, "mm")
+    )
+  pg <- ggplotGrob(p)
+  expect_equal(length(pg$heights), 13)
+
+  pg <- ggplotGrob(p + scale_x_continuous(position = "top"))
+  expect_equal(length(pg$heights), 14)
+  expect_equal(as.character(pg$heights[7]), "1cm")
+})
+
 test_that("y strip labels are rotated when strips are switched", {
   switched <- p + facet_grid(am ~ cyl, switch = "both")