element inheritance in themes

NEWS.md

@@ -129,6 +129,13 @@
 * Fixed a compatibility issue with `ggproto` and R versions prior to 3.1.2.
   (#1444)
 
+<<<<<<< HEAD
+* All elements should now inherit correctly for all themes except theme_void(). (@Katiedaisey, #1555) 
+
+* Inheritance of elements pull from default if parent is element_blank(). (@Katiedaisey, #1565) 
+
+=======
+>>>>>>> hadley/master
 # ggplot2 2.0.0
 
 ## Major changes

R/theme-defaults.r

@@ -77,8 +77,6 @@ theme_grey <- function(base_size = 11, base_family = "") {
                          ),
 
     axis.line =          element_line(),
-    axis.line.x =        element_blank(),
-    axis.line.y =        element_blank(),
     axis.text =          element_text(size = rel(0.8), colour = "grey30"),
     axis.text.x =        element_text(margin = margin(t = 0.8 * half_line / 2), vjust = 1),
     axis.text.y =        element_text(margin = margin(r = 0.8 * half_line / 2), hjust = 1),
@@ -221,8 +219,6 @@ theme_minimal <- function(base_size = 12, base_family = "") {
       strip.background  = element_blank(),
       plot.background   = element_blank(),
       axis.ticks        = element_line(),
-      axis.ticks.x      = element_blank(),
-      axis.ticks.y      = element_blank(),
       axis.ticks.length = unit(1, "lines")
     )
 }
@@ -234,12 +230,8 @@ theme_classic <- function(base_size = 12, base_family = ""){
     theme(
       panel.border     = element_blank(),
       axis.line        = element_line(colour = "black"),
-      panel.grid.major   = element_line(),
-      panel.grid.major.x = element_blank(),
-      panel.grid.major.y = element_blank(),
-      panel.grid.minor   = element_line(),
-      panel.grid.minor.x = element_blank(),
-      panel.grid.minor.y = element_blank(),
+      panel.grid.major = element_blank(),
+      panel.grid.minor = element_blank(),
       strip.background = element_rect(colour = "black", size = 0.5),
       legend.key       = element_blank()
     )
@@ -284,13 +276,18 @@ theme_void <- function(base_size = 12, base_family = "") {
                             margin = margin(), debug = FALSE
                          ),
     plot.margin =        unit(c(0, 0, 0, 0), "lines"),
+    panel.background =   element_blank(),
+    panel.grid.major =   element_blank(),
+    axis.line =          element_blank(),
+    axis.ticks =          element_blank(),
     axis.text.x =        element_blank(),
     axis.text.y =        element_blank(),
     axis.title.x =       element_blank(),
     axis.title.y =       element_blank(),
     legend.text =        element_text(size = rel(0.8)),
     legend.title =       element_blank(),
     strip.text =         element_text(size = rel(0.8)),
+    strip.background =   element_blank(),
 
     complete = TRUE
   )

R/theme-elements.r

@@ -255,7 +255,7 @@ el_def <- function(class = NULL, inherit = NULL, description = NULL) {
   legend.title.align  = el_def("character"),
   legend.position     = el_def("character"),  # Need to also accept numbers
   legend.direction    = el_def("character"),
-  legend.justification = el_def("character"),
+  legend.justification = el_def("character"), # Need to also accept numbers
   legend.box          = el_def("character"),
   legend.box.just     = el_def("character"),
 

R/theme.r

@@ -451,6 +451,11 @@ add_theme <- function(t1, t2, t2name) {
     t1[item] <- list(x)
   }
 
+  # Update inherited items
+  for (item in names(t2)) {
+    t1[[item]] <- calc_element(item, t1)
+  }
+
   # If either theme is complete, then the combined theme is complete
   attr(t1, "complete") <- attr(t1, "complete") || attr(t2, "complete")
   t1
@@ -537,6 +542,12 @@ calc_element <- function(element, theme, verbose = FALSE) {
   # it is of the class specified in .element_tree
   if (!is.null(theme[[element]]) &&
       !inherits(theme[[element]], .element_tree[[element]]$class)) {
+    if (element != "legend.position" && element != "legend.justification")  {
+      stop(element, " should have class ", .element_tree[[element]]$class)
+    }
+  }
+
+  if ((element == "legend.position" || element == "legend.justification") && (class(theme[[element]])[1] != "character" && class(theme[[element]])[1] != "numeric")) {
     stop(element, " should have class ", .element_tree[[element]]$class)
   }
 
@@ -571,20 +582,49 @@ calc_element <- function(element, theme, verbose = FALSE) {
 # @param e2 An element object which e1 inherits from
 combine_elements <- function(e1, e2) {
 
-  # If e2 is NULL, nothing to inherit
-  if (is.null(e2))  return(e1)
+  # If e1 is NULL or element_blank, inherit everything
+  if (is.null(e1) || inherits(e1, "element_blank"))  {e1 <- e2}
+
+  # If e1 is not NULL or blank and e2 is element_blank, inherit everything from root
+  if ((!is.null(e1) || !inherits(e1, "element_blank")) && (is.null(e2) || inherits(e2, "element_blank"))) {
+    e3 <- base_class(e1)
+    n <- vapply(e1[names(e3)], is.null, logical(1))
+    e1[n] <- e3[n]
+  }
 
-  # If e1 is NULL, or if e2 is element_blank, inherit everything from e2
-  if (is.null(e1) || inherits(e2, "element_blank"))  return(e2)
+  # If e1 and e2 are not NULL or blank, inherit from e2 then root
+  if ((!is.null(e1) && !inherits(e1, "element_blank")) && (!is.null(e2) && !inherits(e2, "element_blank"))) {
+    # inherit from e2
+    n <- vapply(e1[names(e2)], is.null, logical(1))
+    e1[n] <- e2[n]
 
-  # If e1 has any NULL properties, inherit them from e2
-  n <- vapply(e1[names(e2)], is.null, logical(1))
-  e1[n] <- e2[n]
+    # inherit missing from base
+    e3 <- base_class(e1 = e1)
+    n <- vapply(e1[names(e3)], is.null, logical(1))
+    e1[n] <- e3[n]
+  }
 
   # Calculate relative sizes
-  if (is.rel(e1$size)) {
+  if (is.rel(e1$size) && !is.null(e2$size)) {
     e1$size <- e2$size * unclass(e1$size)
+  } else if (is.rel(e1$size) && !is.null(e3$size)) {
+    e1$size <- e3$size * unclass(e1$size)
   }
 
-  e1
+  return(e1)
+}
+
+# Fine default properities of element
+#
+# @param e1 An element object
+base_class <- function(e1) {
+  line = element_line(colour = "black", size = 0.5, linetype = 1,lineend = "butt")
+  rect = element_rect(fill = "white", colour = "black",size = 0.5, linetype = 1)
+  text = element_text(family = "", face = "plain",colour = "black", size = 11, lineheight = 0.9, hjust = 0.5, vjust = 0.5, angle = 0, margin = margin(), debug = FALSE)
+  e3 <- class(e1)[1]
+  if (e3 == "element_line") {e3 <- line}
+  else if (e3 == "element_rect") {e3 <- rect}
+  else if (e3 == "element_text") {e3 <- text}
+
+  return(e3)
 }