Add handling of polar axes.

src/axes.jl

@@ -239,8 +239,13 @@ function get_ticks(axis::Axis)
         # discrete ticks...
         axis[:continuous_values], dvals
     elseif ticks == :auto
-        # compute optimal ticks and labels
-        optimal_ticks_and_labels(axis)
+        if ispolar(axis.sps[1]) && axis[:letter] == :x
+            #force theta axis to be full circle
+            (collect(0:pi/4:7pi/4), string.(0:45:315))
+        else
+            # compute optimal ticks and labels
+            optimal_ticks_and_labels(axis)
+        end
     elseif typeof(ticks) <: Union{AVec, Int}
         # override ticks, but get the labels
         optimal_ticks_and_labels(axis, ticks)
@@ -427,7 +432,16 @@ function axis_limits(axis::Axis, should_widen::Bool = default_should_widen(axis)
     if !isfinite(amin) && !isfinite(amax)
         amin, amax = 0.0, 1.0
     end
-    if should_widen
+    if ispolar(axis.sps[1])
+        if axis[:letter] == :x
+            amin, amax = 0, 2pi
+        elseif lims == :auto
+            #widen max radius so ticks dont overlap with theta axis
+            amin, 1.1*amax
+        else
+            amin, amax
+        end
+    elseif should_widen
         widen(amin, amax)
     else
         amin, amax

src/backends/pgfplots.jl

@@ -220,6 +220,8 @@ function pgf_series(sp::Subplot, series::Series)
         # If a marker_z is used pass it as third coordinate to a 2D plot.
         # See "Scatter Plots" in PGFPlots documentation
         d[:x], d[:y], d[:marker_z]
+    elseif ispolar(sp)
+        rad2deg.(d[:x]), d[:y]
     else
         d[:x], d[:y]
     end
@@ -297,14 +299,15 @@ function pgf_axis(sp::Subplot, letter)
     # limits
     # TODO: support zlims
     if letter != :z
-        lims = axis_limits(axis)
+        lims = ispolar(sp) && letter == :x ? rad2deg.(axis_limits(axis)) : axis_limits(axis)
         kw[Symbol(letter,:min)] = lims[1]
         kw[Symbol(letter,:max)] = lims[2]
     end
 
     if !(axis[:ticks] in (nothing, false, :none)) && framestyle != :none
         ticks = get_ticks(axis)
-        push!(style, string(letter, "tick = {", join(ticks[1],","), "}"))
+        tick_values = ispolar(sp) && letter == :x ? rad2deg.(ticks[1]) : ticks[1]
+        push!(style, string(letter, "tick = {", join(tick_values,","), "}"))
         if axis[:showaxis] && axis[:scale] in (:ln, :log2, :log10) && axis[:ticks] == :auto
             # wrap the power part of label with }
             tick_labels = String[begin

src/backends/plotly.jl

@@ -291,6 +291,22 @@ function plotly_axis(axis::Axis, sp::Subplot)
     ax
 end
 
+function plotly_polaraxis(axis::Axis)
+    ax = KW(
+        :visible => axis[:grid],
+        :showline => axis[:grid],
+    )
+
+    if axis[:letter] == :x
+        ax[:range] = rad2deg.(axis_limits(axis))
+    else
+        ax[:range] = axis_limits(axis)
+        ax[:orientation] = 0
+    end
+
+    ax
+end
+
 function plotly_layout(plt::Plot)
     d_out = KW()
 
@@ -345,6 +361,9 @@ function plotly_layout(plt::Plot)
                     ),
                 ),
             )
+        elseif ispolar(sp)
+            d_out[Symbol("angularaxis$spidx")] = plotly_polaraxis(sp[:xaxis])
+            d_out[Symbol("radialaxis$spidx")] = plotly_polaraxis(sp[:yaxis])
         else
             d_out[Symbol("xaxis$spidx")] = plotly_axis(sp[:xaxis], sp)
             d_out[Symbol("yaxis$spidx")] = plotly_axis(sp[:yaxis], sp)

src/backends/pyplot.jl

@@ -1054,6 +1054,9 @@ function _before_layout_calcs(plt::Plot{PyPlotBackend})
             end
             py_set_scale(ax, axis)
             py_set_lims(ax, axis)
+            if ispolar(sp) && letter == :y
+                ax[:set_rlabel_position](0)
+            end
             ticks = sp[:framestyle] == :none ? nothing : get_ticks(axis)
             # don't show the 0 tick label for the origin framestyle
             if sp[:framestyle] == :origin && length(ticks) > 1
@@ -1080,6 +1083,8 @@ function _before_layout_calcs(plt::Plot{PyPlotBackend})
                     linewidth = axis[:gridlinewidth],
                     alpha = axis[:gridalpha])
                 ax[:set_axisbelow](true)
+            else
+                pyaxis[:grid](false)
             end
             py_set_axis_colors(sp, ax, axis)
         end