sample ticks if too many discrete values; use get_ticks in plotly to fix discrete ticks; allow ticks==false in pyplot; closes #356

src/axes.jl

@@ -122,7 +122,14 @@ function get_ticks(axis::Axis)
     ticks = axis[:ticks]
     dvals = axis[:discrete_values]
     if !isempty(dvals) && ticks == :auto
-        axis[:continuous_values], dvals
+        cv, dv = axis[:continuous_values], dvals
+        # TODO: better/smarter cutoff values for sampling ticks
+        if length(cv) > 30
+            rng = Int[round(Int,i) for i in linspace(1, length(cv), 15)]
+            cv[rng], dv[rng]
+        else
+            cv, dv
+        end
     else
         ticks
     end

src/backends/plotly.jl

@@ -190,7 +190,7 @@ function plotly_axis(axis::Axis, sp::Subplot)
         end
 
         # ticks
-        ticks = axis[:ticks]
+        ticks = get_ticks(axis)
         if ticks != :auto
             ttype = ticksType(ticks)
             if ttype == :ticks

src/backends/pyplot.jl

@@ -935,7 +935,7 @@ end
 function py_set_ticks(ax, ticks, letter)
     ticks == :auto && return
     axis = ax[Symbol(letter,"axis")]
-    if ticks == :none || ticks == nothing
+    if ticks == :none || ticks == nothing || ticks == false
         kw = KW()
         for dir in (:top,:bottom,:left,:right)
             kw[dir] = kw[Symbol(:label,dir)] = "off"