make axis aware of reverse settings

Author: teunbrand

R/guide-axis.R

@@ -167,32 +167,36 @@ GuideAxis <- ggproto(
     }
 
     opposite <- setdiff(c("x", "y"), aesthetic)
-    opposite_value <- if (position %in% c("top", "right")) -Inf else Inf
 
-    data_frame(
-      !!aesthetic := value,
-      !!opposite  := opposite_value
-    )
+    data_frame(!!aesthetic := value)
   },
 
   transform = function(self, params, coord, panel_params) {
     key <- params$key
     position <- params$position
     check <- FALSE
 
+    aesthetic <- names(key)[!grepl("^\\.", names(key))]
+    ortho     <- setdiff(c("x", "y"), params$aesthetic)
+    override  <- switch(position %||% "", bottom = , left = -Inf, Inf)
+
+    if (!(panel_params$reverse %||% "none") %in% c("xy", ortho)) {
+      override <- -override
+    }
+
     if (!(is.null(position) || nrow(key) == 0)) {
       check <- TRUE
-      aesthetics <- names(key)[!grepl("^\\.", names(key))]
-      if (!all(c("x", "y") %in% aesthetics)) {
-        other_aesthetic <- setdiff(c("x", "y"), aesthetics)
-        override_value <- if (position %in% c("bottom", "left")) -Inf else Inf
-        key[[other_aesthetic]] <- override_value
+      if (!all(c("x", "y") %in% aesthetic)) {
+        key[[ortho]] <- override
       }
       key <- coord$transform(key, panel_params)
       params$key <- key
     }
 
     if (!is.null(params$decor)) {
+      if (!ortho %in% names(params$decor)) {
+        params$decor[[ortho]] <- override
+      }
       params$decor <- coord_munch(coord, params$decor, panel_params)
 
       if (!coord$is_linear()) {