Alpha affects both fill and colour.

Fixes #1371

Author: hadley

NEWS.md

@@ -154,6 +154,8 @@ All defunct functions have been removed.
     * Default margins scale with the theme font size, so the appearance at 
       larger font sizes should be considerably improved (#1228). 
 
+* `alpha` now affects both fill and colour aesthetics (#1371).
+
 * `element_text()` gains a margins argument which allows you to add additional
   padding around text elements. To help see what's going on use `debug = TRUE` 
   to display the text region and anchors.

R/aes-colour-fill-alpha.r

@@ -44,10 +44,6 @@
 #' h + geom_point(alpha = 0.5)
 #' h + geom_point(alpha = 1/10)
 #'
-#' #If a geom uses both fill and colour, alpha will only modify the fill colour
-#' c + geom_bar(fill = "dark grey", colour = "black")
-#' c + geom_bar(fill = "dark grey", colour = "black", alpha = 1/3)
-#'
 #' # Alpha can also be used to add shading
 #' j <- b + geom_line()
 #' j

R/geom-polygon.r

@@ -87,7 +87,7 @@ GeomPolygon <- ggproto("GeomPolygon", Geom,
       polygonGrob(munched$x, munched$y, default.units = "native",
         id = munched$group,
         gp = gpar(
-          col = first_rows$colour,
+          col = alpha(first_rows$colour, first_rows$alpha),
           fill = alpha(first_rows$fill, first_rows$alpha),
           lwd = first_rows$size * .pt,
           lty = first_rows$linetype

R/geom-rect.r

@@ -52,7 +52,7 @@ GeomRect <- ggproto("GeomRect", Geom,
         default.units = "native",
         just = c("left", "top"),
         gp = gpar(
-          col = coords$colour,
+          col = alpha(coords$colour, coords$alpha),
           fill = alpha(coords$fill, coords$alpha),
           lwd = coords$size * .pt,
           lty = coords$linetype,

R/geom-ribbon.r

@@ -92,7 +92,7 @@ GeomRibbon <- ggproto("GeomRibbon", Geom,
       default.units = "native",
       gp = gpar(
         fill = alpha(aes$fill, aes$alpha),
-        col = aes$colour,
+        col = alpha(aes$colour, aes$alpha),
         lwd = aes$size * .pt,
         lty = aes$linetype)
     ))