Add default_anim_opts()

Lets us define default animation options by animation family that can be overridden by the user at runtime. Demonstration of usage with animate_gather() and animate_spread()

R/animate_tidyr.R

@@ -1,4 +1,3 @@
-
 #' Animates the gather function
 #'
 #' @param w a data_frame in the wide format
@@ -29,7 +28,8 @@
 #'   # if you want to have a less detailed animation, you can also use
 #'   animate_gather(wide, "person", "sales", -year, export = "gif", detailed = FALSE)
 #' }
-animate_gather <- function(w, key, value, ..., export = "gif", detailed = TRUE, anim_opts = anim_options()) {
+animate_gather <- function(w, key, value, ..., export = "gif", detailed = TRUE, anim_opts = NULL) {
+  anim_opts <- default_anim_opts("gather", anim_opts)
   lhs <- w
   rhs <- tidyr::gather(w, !!key, !!value, ...)
 
@@ -88,7 +88,8 @@ animate_gather <- function(w, key, value, ..., export = "gif", detailed = TRUE,
 #'   # if you want to have a less detailed animation, you can also use
 #'   animate_spread(long, key = "person", value = "sales", export = "gif", detailed = FALSE)
 #' }
-animate_spread <- function(l, key, value, export = "gif", detailed = TRUE, ..., anim_opts = anim_options()) {
+animate_spread <- function(l, key, value, export = "gif", detailed = TRUE, ..., anim_opts = NULL) {
+  anim_opts <- default_anim_opts("spread", anim_opts)
 
   lhs <- l
   rhs <- tidyr::spread(l, key = key, value = value)

R/plot_helpers.R

@@ -89,6 +89,23 @@ remove_default_anim_opts <- function(ao) {
   ao[!same]
 }
 
+default_anim_opts <- function(family, ao_custom = NULL) {
+  family_options <- c("join", "set", "gather", "spread")
+  family <- match.arg(family, family_options, several.ok = FALSE)
+  ao_default <- switch(
+    family,
+    "gather" = anim_options(enter = enter_fade(), exit = exit_fade(),
+                            ease_default = "sine-in-out",
+                            ease_other = list(y = "cubic-out", x = "cubic-in")),
+    "spread" = anim_options(enter = enter_fade(), exit = exit_fade(),
+                            ease_default = "sine-in-out",
+                            ease_other = list(y = "cubic-out", x = "cubic-in")),
+    anim_options()
+  )
+  if (is.null(ao_custom)) return(ao_default)
+  merge(ao_custom, ao_default)
+}
+
 #' Animates a plot
 #'
 #' @param d a processed dataset