POC: ignore() for aesthetic evaluation.

R/aes-evaluation.R

@@ -204,6 +204,12 @@ stage_scaled <- function(start = NULL, after_stat = NULL, after_scale = NULL) {
   after_scale
 }
 
+#' @rdname aes_eval
+#' @export
+ignore <- function(x) {
+  x
+}
+
 # Regex to determine if an identifier refers to a calculated aesthetic
 match_calculated_aes <- "^\\.\\.([a-zA-Z._]+)\\.\\.$"
 
@@ -221,6 +227,10 @@ is_scaled_aes <- function(aesthetics) {
 is_staged_aes <- function(aesthetics) {
   vapply(aesthetics, is_staged, logical(1), USE.NAMES = FALSE)
 }
+is_ignored_aes <- function(aesthetics) {
+  vapply(aesthetics, is_ignored, logical(1), USE.NAMES = FALSE)
+}
+
 is_calculated <- function(x, warn = FALSE) {
   if (is_call(get_expr(x), "after_stat")) {
     return(TRUE)
@@ -263,6 +273,9 @@ is_scaled <- function(x) {
 is_staged <- function(x) {
   is_call(get_expr(x), "stage")
 }
+is_ignored <- function(x) {
+  is_call(get_expr(x), "ignore")
+}
 
 # Strip dots from expressions
 strip_dots <- function(expr, env, strip_pronoun = FALSE) {

R/annotation.R

@@ -70,8 +70,17 @@ annotate <- function(geom, x = NULL, y = NULL, xmin = NULL, xmax = NULL,
     details <- paste0(names(aesthetics)[bad], " (", lengths[bad], ")")
     cli::cli_abort("Unequal parameter lengths: {details}")
   }
-
   data <- data_frame0(!!!position, .size = n)
+
+  # Re-inject potential `ignore()` expressions
+  mapping <- aes_all(names(data))
+  call <- call_match(fn = annotate)
+  aesthetics <- intersect(names(call), names(mapping))
+  for (aes in aesthetics[is_ignored_aes(call[aesthetics])]) {
+    expr <- quo_get_expr(mapping[[aes]])
+    mapping[[aes]] <- quo(ignore(!!expr))
+  }
+
   layer(
     geom = geom,
     params = list(
@@ -81,7 +90,7 @@ annotate <- function(geom, x = NULL, y = NULL, xmin = NULL, xmax = NULL,
     stat = StatIdentity,
     position = PositionIdentity,
     data = data,
-    mapping = aes_all(names(data)),
+    mapping = mapping,
     inherit.aes = FALSE,
     show.legend = FALSE
   )

R/layer.R

@@ -344,7 +344,8 @@ Layer <- ggproto("Layer", NULL,
     aesthetics <- defaults(aesthetics, self$stat$default_aes)
     aesthetics <- compact(aesthetics)
 
-    new <- strip_dots(aesthetics[is_calculated_aes(aesthetics) | is_staged_aes(aesthetics)])
+    new <- aesthetics[!is_ignored_aes(aesthetics)]
+    new <- strip_dots(new[is_calculated_aes(new) | is_staged_aes(new)])
     if (length(new) == 0) return(data)
 
     # data needs to be non-scaled
@@ -428,7 +429,38 @@ Layer <- ggproto("Layer", NULL,
     }
 
     data <- self$geom$handle_na(data, self$computed_geom_params)
+
+    ignored <- self$ignored_aesthetics()
+    if (any(ignored %in% c(ggplot_global$x_aes, ggplot_global$y_aes))) {
+      # We temporarily redefine x/y aesthetics to have coords skip
+      # transformation of ignored aesthetics
+      local_bindings(
+        x_aes = setdiff(ggplot_global$x_aes, ignored),
+        y_aes = setdiff(ggplot_global$y_aes, ignored),
+        .env = ggplot_global
+      )
+    }
+
     self$geom$draw_layer(data, self$computed_geom_params, layout, layout$coord)
+  },
+
+  ignored_aesthetics = function(self) {
+    aesthetics <- self$computed_mapping
+    names(aesthetics)[is_ignored_aes(aesthetics)]
+  },
+
+  apply_ignore = function(self, data) {
+    ignored <- self$ignored_aesthetics()
+    ignored <- names(data) %in% ignored
+    names(data)[ignored] <- paste0(".ignored_", names(data)[ignored])
+    data
+  },
+
+  undo_ignore = function(self, data) {
+    ignored <- self$ignored_aesthetics()
+    ignored <- names(data) %in% paste0(".ignored_", ignored)
+    names(data)[ignored] <- gsub("^\\.ignored_", "", names(data)[ignored])
+    data
   }
 )
 

R/plot-build.R

@@ -51,6 +51,7 @@ ggplot_build.ggplot <- function(plot) {
 
   # Compute aesthetics to produce data with generalised variable names
   data <- by_layer(function(l, d) l$compute_aesthetics(d, plot), layers, data, "computing aesthetics")
+  data <- by_layer(function(l, d) l$apply_ignore(d), layers, data, "ignoring aesthetics")
 
   # Transform all scales
   data <- lapply(data, scales$transform_df)
@@ -62,6 +63,7 @@ ggplot_build.ggplot <- function(plot) {
 
   layout$train_position(data, scale_x(), scale_y())
   data <- layout$map_position(data)
+  data <- by_layer(function(l, d) l$undo_ignore(d), layers, data, "unignoring aesthetics")
 
   # Apply and map statistics
   data <- by_layer(function(l, d) l$compute_statistic(d, layout), layers, data, "computing stat")
@@ -79,6 +81,7 @@ ggplot_build.ggplot <- function(plot) {
   # Reset position scales, then re-train and map.  This ensures that facets
   # have control over the range of a plot: is it generated from what is
   # displayed, or does it include the range of underlying data
+  data <- by_layer(function(l, d) l$apply_ignore(d), layers, data, "ignoring aesthetics")
   layout$reset_scales()
   layout$train_position(data, scale_x(), scale_y())
   layout$setup_panel_params()
@@ -90,6 +93,7 @@ ggplot_build.ggplot <- function(plot) {
     lapply(data, npscales$train_df)
     data <- lapply(data, npscales$map_df)
   }
+  data <- by_layer(function(l, d) l$undo_ignore(d), layers, data, "unignoring aesthetics")
 
   # Fill in defaults etc.
   data <- by_layer(function(l, d) l$compute_geom_2(d), layers, data, "setting up geom aesthetics")

R/position-.R

@@ -78,13 +78,14 @@ transform_position <- function(df, trans_x = NULL, trans_y = NULL, ...) {
   # Treat df as list during transformation for faster set/get
   oldclass <- class(df)
   df <- unclass(df)
-  scales <- aes_to_scale(names(df))
 
   if (!is.null(trans_x)) {
-    df[scales == "x"] <- lapply(df[scales == "x"], trans_x, ...)
+    is_x <- names(df) %in% ggplot_global$x_aes
+    df[is_x] <- lapply(df[is_x], trans_x, ...)
   }
   if (!is.null(trans_y)) {
-    df[scales == "y"] <- lapply(df[scales == "y"], trans_y, ...)
+    is_y <- names(df) %in% ggplot_global$y_aes
+    df[is_y] <- lapply(df[is_y], trans_y, ...)
   }
 
   class(df) <- oldclass

R/scales-.R

@@ -145,6 +145,7 @@ ScalesList <- ggproto("ScalesList", NULL,
     if (is.null(aesthetics)) {
       return()
     }
+    aesthetics <- aesthetics[!is_ignored_aes(aesthetics)]
     names(aesthetics) <- unlist(lapply(names(aesthetics), aes_to_scale))
 
     new_aesthetics <- setdiff(names(aesthetics), self$input())