use fortify.grouped_df() instead of ggplot.grouped_df() (#2623)

* use fortify.grouped_df() instead of ggplot.grouped_df()

* fix the signature of fortify.grouped_df()

Author: yutannihilation

NAMESPACE

@@ -35,14 +35,13 @@ S3method(fortify,confint.glht)
 S3method(fortify,data.frame)
 S3method(fortify,default)
 S3method(fortify,glht)
+S3method(fortify,grouped_df)
 S3method(fortify,lm)
 S3method(fortify,map)
 S3method(fortify,summary.glht)
 S3method(fortify,tbl)
 S3method(ggplot,"function")
-S3method(ggplot,data.frame)
 S3method(ggplot,default)
-S3method(ggplot,grouped_df)
 S3method(ggplot_add,"NULL")
 S3method(ggplot_add,Coord)
 S3method(ggplot_add,Facet)

R/fortify.r

@@ -20,6 +20,11 @@ fortify.NULL <- function(model, data, ...) waiver()
 #' @export
 fortify.function <- function(model, data, ...) model
 #' @export
+fortify.grouped_df <- function(model, data, ...) {
+  model$.group <- dplyr::group_indices(model)
+  model
+}
+#' @export
 fortify.default <- function(model, data, ...) {
   msg <- paste0(
     "`data` must be a data frame, or other object coercible by `fortify()`, ",

R/plot.r

@@ -77,23 +77,12 @@ ggplot <- function(data = NULL, mapping = aes(), ...,
 #' @export
 ggplot.default <- function(data = NULL, mapping = aes(), ...,
                            environment = parent.frame()) {
-  ggplot.data.frame(fortify(data, ...), mapping, environment = environment)
-}
-
-#' @export
-ggplot.function <- function(data = NULL, mapping = aes(), ...,
-                           environment = parent.frame()) {
-  # Added to avoid functions end in ggplot.default
-  stop("You're passing a function as global data.\nHave you misspelled the `data` argument in `ggplot()`", call. = FALSE)
-}
-
-#' @export
-ggplot.data.frame <- function(data, mapping = aes(), ...,
-                              environment = parent.frame()) {
   if (!missing(mapping) && !inherits(mapping, "uneval")) {
     stop("Mapping should be created with `aes() or `aes_()`.", call. = FALSE)
   }
 
+  data <- fortify(data, ...)
+
   p <- structure(list(
     data = data,
     layers = list(),
@@ -112,11 +101,10 @@ ggplot.data.frame <- function(data, mapping = aes(), ...,
 }
 
 #' @export
-ggplot.grouped_df <- function(data, mapping = aes(), ...,
-                               environment = parent.frame()) {
-
-  data$.group <- dplyr::group_indices(data)
-  ggplot.data.frame(data, mapping = mapping, ..., environment = environment)
+ggplot.function <- function(data = NULL, mapping = aes(), ...,
+                            environment = parent.frame()) {
+  # Added to avoid functions end in ggplot.default
+  stop("You're passing a function as global data.\nHave you misspelled the `data` argument in `ggplot()`", call. = FALSE)
 }
 
 plot_clone <- function(plot) {