From a6588daa3e92312261129f2bbe85ebb9b858306d Mon Sep 17 00:00:00 2001
From: Daniel Schwabeneder <daschw@disroot.org>
Date: Fri, 26 Apr 2019 13:17:29 +0200
Subject: [PATCH] allow negative radii in polar plots for pyplot

---
 src/backends/pyplot.jl | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/backends/pyplot.jl b/src/backends/pyplot.jl
index d3e0e091..3618412f 100644
--- a/src/backends/pyplot.jl
+++ b/src/backends/pyplot.jl
@@ -376,6 +376,18 @@ function py_add_series(plt::Plot{PyPlotBackend}, series::Series)
     elseif st == :shape
         x, y = shape_data(series)
     end
+
+    if ispolar(series)
+        # make negative radii positive and flip the angle
+        # (PyPlot ignores negative radii)
+        for i in eachindex(y)
+            if y[i] < 0
+                y[i] = -y[i]
+                x[i] -= π
+            end
+        end
+    end
+
     xyargs = (st in _3dTypes ? (x,y,z) : (x,y))
 
     # handle zcolor and get c/cmap