Move setup_layer() to plot build.

Author: clauswilke

R/layer.r

@@ -199,9 +199,10 @@ Layer <- ggproto("Layer", NULL,
     }
   },
 
-  # hook to allow a layer access to global plot data
-  # as the plot is constructed.
-  setup_layer = function(self, plot) {
+  # hook to allow a layer access to the final layer data
+  # in input form and to global plot info
+  setup_layer = function(self, data, plot) {
+    data
   },
 
   compute_aesthetics = function(self, data, plot) {

R/plot-build.r

@@ -39,10 +39,15 @@ ggplot_build.ggplot <- function(plot) {
     out
   }
 
+  # Allow all layers to make any final adjustments based
+  # on raw input data and plot info
+  data <- layer_data
+  data <- by_layer(function(l, d) l$setup_layer(d, plot))
+
   # Initialise panels, add extra data for margins & missing faceting
   # variables, and add on a PANEL variable to data
   layout <- create_layout(plot$facet, plot$coordinates)
-  data <- layout$setup(layer_data, plot$data, plot$plot_env)
+  data <- layout$setup(data, plot$data, plot$plot_env)
 
   # Compute aesthetics to produce data with generalised variable names
   data <- by_layer(function(l, d) l$compute_aesthetics(d, plot))

R/plot-construction.r

@@ -153,10 +153,6 @@ ggplot_add.list <- function(object, plot, object_name) {
 }
 #' @export
 ggplot_add.Layer <- function(object, plot, object_name) {
-  # allow the layer to modify itself based on plot object
-  # useful for layers that need to access the global data
-  object$setup_layer(plot)
-
   plot$layers <- append(plot$layers, object)
 
   # Add any new labels

R/sf.R

@@ -148,21 +148,20 @@ stat_sf <- function(mapping = NULL, data = NULL, geom = "rect",
 #' @usage NULL
 #' @format NULL
 LayerSf <- ggproto("LayerSf", Layer,
-  setup_layer = function(self, plot) {
-    # Automatically determine the name of the geometry column
-    # and add the mapping if it doesn't exist
-    data <- self$layer_data(plot$data)
+  setup_layer = function(self, data, plot) {
+    # process generic layer setup first
+    data <- ggproto_parent(Layer, self)$setup_layer(data, plot)
 
+    # automatically determine the name of the geometry column
+    # and add the mapping if it doesn't exist
     if ((isTRUE(self$inherit.aes) && is.null(self$mapping$geometry) && is.null(plot$mapping$geometry)) ||
         (!isTRUE(self$inherit.aes) && is.null(self$mapping$geometry))) {
-      if (!is.waive(data) && is_sf(data)) {
+      if (is_sf(data)) {
         geometry_col <- attr(data, "sf_column")
         self$mapping$geometry <- as.name(geometry_col)
       }
     }
-
-    # call parent for generic layer setup
-    ggproto_parent(Layer, self)$setup_layer(plot)
+    data
   }
 )