From 30eebc9bcf6b8ec671b94aa09bed43068ea84a2f Mon Sep 17 00:00:00 2001
From: Christoph Deil <Deil.Christoph@gmail.com>
Date: Sat, 15 Sep 2018 13:17:53 +0200
Subject: [PATCH] Add SkyRegion.plot method

---
 docs/plot_example.py            |  1 +
 regions/core/core.py            | 23 +++++++++++++++++++++++
 regions/core/tests/test_core.py | 16 ++++++++++++++++
 3 files changed, 40 insertions(+)
 create mode 100644 regions/core/tests/test_core.py

diff --git a/docs/plot_example.py b/docs/plot_example.py
index c650e9dc..753cff23 100644
--- a/docs/plot_example.py
+++ b/docs/plot_example.py
@@ -28,5 +28,6 @@
     pix_region = region.to_pixel(wcs=wcs)
 
     pix_region.plot(ax=ax, edgecolor='yellow', facecolor='yellow', alpha=0.5, lw=3)
+    region.plot(edgecolor='red', lw=1)
 
 plt.show()
diff --git a/regions/core/core.py b/regions/core/core.py
index 7315b49a..6c31bb0e 100644
--- a/regions/core/core.py
+++ b/regions/core/core.py
@@ -378,3 +378,26 @@ def to_pixel(self, wcs):
         pixel_region : `~regions.PixelRegion` object.
         """
         raise NotImplementedError
+
+    def plot(self, ax=None, **kwargs):
+        """
+        Plot region using matplotlib.
+
+        TODO: describe once we know what API we want.
+        """
+        import matplotlib.pyplot as plt
+
+        if ax is None:
+            ax = plt.gca()
+
+        if not hasattr(ax, 'wcs'):
+            raise TypeError(
+                'SkyRegion plot only works on WCSAxes. '
+                'Consider using WCSAxes or use sky_region.to_pixel(wcs).plot(...).'
+            )
+
+        pix_region = self.to_pixel(ax.wcs)
+        artist = pix_region.as_artist(**kwargs)
+        ax.add_artist(artist)
+
+        return ax
diff --git a/regions/core/tests/test_core.py b/regions/core/tests/test_core.py
new file mode 100644
index 00000000..58a90112
--- /dev/null
+++ b/regions/core/tests/test_core.py
@@ -0,0 +1,16 @@
+# Licensed under a 3-clause BSD style license - see LICENSE.rst
+from __future__ import absolute_import, division, print_function, unicode_literals
+import pytest
+from ...shapes import CircleSkyRegion, PointSkyRegion
+
+try:
+    import matplotlib
+
+    HAS_MATPLOTLIB = True
+except:
+    HAS_MATPLOTLIB = False
+
+
+@pytest.mark.skipif('not HAS_MATPLOTLIB')
+def test_sky_region_plot():
+    assert 'TODO'