From f2235abf08cca48209954c7378075e55efd3f7f2 Mon Sep 17 00:00:00 2001
From: Daniel Schwabeneder <daniel.schwabeneder@openmailbox.org>
Date: Mon, 6 Mar 2017 23:52:59 +0100
Subject: [PATCH] Added logic to choose *round* DateTime tick positions

---
 src/axes.jl    | 7 +++++++
 src/recipes.jl | 7 +++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/axes.jl b/src/axes.jl
index b9840e7a..dd36f824 100644
--- a/src/axes.jl
+++ b/src/axes.jl
@@ -156,6 +156,13 @@ function optimal_ticks_and_labels(axis::Axis, ticks = nothing)
     scale = axis[:scale]
     sf = scalefunc(scale)
 
+    # If the axis input was a Date or DateTime use a special logic to find
+    # "round" Date(Time)s as ticks
+    # TODO: maybe: non-trivial scale (:ln, :log2, :log10) for date/datetime
+    if axis[:formatter] in (dateformatter, datetimeformatter) && scale == :identity
+        return optimize_datetime_ticks(amin, amax; k_min = 2, k_max = 4)
+    end
+
     # get a list of well-laid-out ticks
     scaled_ticks = if ticks == nothing
         optimize_ticks(
diff --git a/src/recipes.jl b/src/recipes.jl
index 3fa7a46e..a4f576a3 100644
--- a/src/recipes.jl
+++ b/src/recipes.jl
@@ -792,8 +792,11 @@ abline!(args...; kw...) = abline!(current(), args...; kw...)
 # -------------------------------------------------
 # Dates
 
-@recipe f(::Type{Date}, dt::Date) = (dt -> convert(Int,dt), dt -> string(convert(Date,dt)))
-@recipe f(::Type{DateTime}, dt::DateTime) = (dt -> convert(Int,dt), dt -> string(convert(DateTime,dt)))
+dateformatter(dt) = string(convert(Date, convert(DateTime, dt)))
+datetimeformatter(dt) = string(convert(DateTime, dt))
+
+@recipe f(::Type{Date}, dt::Date) = (dt -> convert(Int, convert(DateTime, dt)), dateformatter)
+@recipe f(::Type{DateTime}, dt::DateTime) = (dt -> convert(Int,dt), datetimeformatter)
 
 # -------------------------------------------------
 # Complex Numbers