consider fillrange in step recipes

src/recipes.jl

@@ -140,11 +140,32 @@ function make_steps(x, y, st)
     newx, newy
 end
 
+make_steps(x, st) = x
+function make_steps(x::AbstractArray, st)
+    n = length(x)
+    n == 0 && return zeros(0)
+    newx = zeros(2n - 1)
+    for i in 1:n
+        idx = 2i - 1
+        newx[idx] = x[i]
+        if i > 1
+            newx[idx - 1] = x[st == :pre ? i : i - 1]
+        end
+    end
+    return newx
+end
+make_steps(t::Tuple, st) = Tuple(make_steps(ti, st) for ti in t)
+
+
 # create a path from steps
 @recipe function f(::Type{Val{:steppre}}, x, y, z)
-    plotattributes[:x], plotattributes[:y] = make_steps(x, y, :steppre)
+    plotattributes[:x] = make_steps(x, :post)
+    plotattributes[:y] = make_steps(y, :pre)
     seriestype := :path
 
+    # handle fillrange
+    plotattributes[:fillrange] = make_steps(plotattributes[:fillrange], :pre)
+
     # create a secondary series for the markers
     if plotattributes[:markershape] != :none
         @series begin
@@ -163,9 +184,13 @@ end
 
 # create a path from steps
 @recipe function f(::Type{Val{:steppost}}, x, y, z)
-    plotattributes[:x], plotattributes[:y] = make_steps(x, y, :steppost)
+    plotattributes[:x] = make_steps(x, :pre)
+    plotattributes[:y] = make_steps(y, :post)
     seriestype := :path
 
+    # handle fillrange
+    plotattributes[:fillrange] = make_steps(plotattributes[:fillrange], :post)
+
     # create a secondary series for the markers
     if plotattributes[:markershape] != :none
         @series begin