Ensure correct positioning of dots in geom_dotplot

NEWS.md

@@ -1,5 +1,8 @@
 # ggplot2 (development version)
 
+* Fix bug in `geom_dotplot()` where dots would be positioned wrong with 
+  `stackgroups = TRUE` (@thomasp85, #1745)
+
 * Make sure position_jitter creates the same jittering independent of whether it
   is called by name or with constructor (@thomasp85, #2507)
 

R/geom-dotplot.r

@@ -208,25 +208,31 @@ GeomDotplot <- ggproto("GeomDotplot", Geom,
       stackdots <- function(a)  a - 1 - floor(max(a - 1) / 2)
       stackaxismin <- -.5
       stackaxismax <- .5
+    } else {
+      abort(glue('{params$stackdir} is not a recognized value for `stackdir`. Use "up", "down", "center", or "centerwhole"'))
     }
 
-
     # Fill the bins: at a given x (or y), if count=3, make 3 entries at that x
     data <- data[rep(1:nrow(data), data$count), ]
 
     # Next part will set the position of each dot within each stack
     # If stackgroups=TRUE, split only on x (or y) and panel; if not stacking, also split by group
     plyvars <- params$binaxis %||% "x"
+    stackaxis <- setdiff(c("x", "y"), plyvars)
     plyvars <- c(plyvars, "PANEL")
     if (is.null(params$stackgroups) || !params$stackgroups)
       plyvars <- c(plyvars, "group")
 
+    if (stackaxis == "x") {
+      plyvars <- c(plyvars, "x")
+    }
+
     # Within each x, or x+group, set countidx=1,2,3, and set stackpos according to stack function
     data <- dapply(data, plyvars, function(xx) {
-            xx$countidx <- 1:nrow(xx)
-            xx$stackpos <- stackdots(xx$countidx)
-            xx
-          })
+      xx$countidx <- 1:nrow(xx)
+      xx$stackpos <- stackdots(xx$countidx)
+      xx
+    })
 
 
     # Set the bounding boxes for the dots

tests/figs/deps.txt

@@ -1,3 +1,3 @@
 - vdiffr-svg-engine: 1.0
 - vdiffr: 0.3.3
-- freetypeharfbuzz: 0.2.5
+- freetypeharfbuzz: 0.2.6