Add arrow to line params

Author: JakeRuss

R/geom-sf.R

@@ -128,14 +128,15 @@ GeomSf <- ggproto("GeomSf", Geom,
 
   draw_panel = function(data, panel_params, coord, legend = NULL,
                         lineend = "butt", linejoin = "round", linemitre = 10,
-                        na.rm = TRUE) {
+                        arrow = NULL, na.rm = TRUE) {
     if (!inherits(coord, "CoordSf")) {
       abort("geom_sf() must be used with coord_sf()")
     }
 
     # Need to refactor this to generate one grob per geometry type
     coord <- coord$transform(data, panel_params)
-    sf_grob(coord, lineend = lineend, linejoin = linejoin, linemitre = linemitre, na.rm = na.rm)
+    sf_grob(coord, lineend = lineend, linejoin = linejoin, linemitre = linemitre,
+            arrow = arrow, na.rm = na.rm)
   },
 
   draw_key = function(data, params, size) {
@@ -160,7 +161,8 @@ default_aesthetics <- function(type) {
   }
 }
 
-sf_grob <- function(x, lineend = "butt", linejoin = "round", linemitre = 10, na.rm = TRUE) {
+sf_grob <- function(x, lineend = "butt", linejoin = "round", linemitre = 10,
+                    arrow = NULL, na.rm = TRUE) {
   type <- sf_types[sf::st_geometry_type(x$geometry)]
   is_point <- type == "point"
   is_line <- type == "line"
@@ -208,7 +210,8 @@ sf_grob <- function(x, lineend = "butt", linejoin = "round", linemitre = 10, na.
   lty <- x$linetype %||% defaults$linetype[type_ind]
   gp <- gpar(
     col = col, fill = fill, fontsize = fontsize, lwd = lwd, lty = lty,
-    lineend = lineend, linejoin = linejoin, linemitre = linemitre
+    lineend = lineend, linejoin = linejoin, linemitre = linemitre,
+    arrow = arrow
   )
   sf::st_as_grob(x$geometry, pch = pch, gp = gp)
 }