Update plot_image.py's interpolation extraction for Matplotlib 0.91.2.

I'd written it for v1.0.1, but the department server is still running
0.91.2, which only sets the interpolation dictionary for AxesImage
instances (not for the class itself).

diff --git a/src/plot_image/plot_image.py b/src/plot_image/plot_image.py
index 8c0a33806af9147b32fc0469a9cb4e57f7420266..dd772a0476c21d4d6cd8786666101956d27c1a46 100755 (executable)
--- a/src/plot_image/plot_image.py
+++ b/src/plot_image/plot_image.py
@@ -174,6 +174,17 @@ def plot(X, Y, Z, full=False, title=None, contours=None, interpolation=None,
     return fig
 
 
+def get_possible_interpolations():
+    try:  # Matplotlib v1.0.1
+        return sorted(matplotlib.image.AxesImage._interpd.keys())
+    except AttributeError:
+        try:  # Matplotlib v0.91.2
+            return sorted(matplotlib.image.AxesImage(None)._interpd.keys())
+        except AttributeError:
+            # give up ;)
+            pass
+    return ['nearest']
+
 def test():
     import doctest
     results = doctest.testmod()
@@ -231,7 +242,7 @@ def main(argv=None):
                  help='Title (%default)')
     p.add_option('--test', dest='test', action='store_true',
                  help='Run internal tests and exit.')
-    interpolations = sorted(matplotlib.image.AxesImage._interpd.keys())
+    interpolations = get_possible_interpolations()
     p.add_option('--interpolation', dest='interpolation', default='nearest',
                  help=('Interpolation scheme (for false color images) from %s '
                        '(%%default)') % ', '.join(interpolations))