matplotlylib - change showline==True default to track
from https://github.com/plotly/python-api/issues/46

diff --git a/plotly/matplotlylib/mpltools.py b/plotly/matplotlylib/mpltools.py
index 644d2aa42..71eccaf24 100644
--- a/plotly/matplotlylib/mpltools.py
+++ b/plotly/matplotlylib/mpltools.py
@@ -194,6 +194,17 @@ def get_axes_bounds(fig):
     return (x_min, x_max), (y_min, y_max)
 
 
+def get_axis_mirror(main_spine, mirror_spine):
+    if main_spine and mirror_spine:
+        return 'ticks'
+    elif main_spine and not mirror_spine:
+        return False
+    elif not main_spine and mirror_spine:
+        return False  # can't handle this case yet!
+    else:
+        return False  # nuttin'!
+
+
 def get_bar_gap(bar_starts, bar_ends, tol=1e-10):
     if len(bar_starts) == len(bar_ends) and len(bar_starts) > 1:
         sides1 = bar_starts[1:]
@@ -224,6 +235,24 @@ def get_rect_ymax(data):
     """Find maximum y value from four (x,y) vertices."""
     return max(data[0][1], data[1][1], data[2][1], data[3][1])
 
+def get_spine_visible(ax, spine_key):
+    """Return some spine parameters for the spine, `spine_key`."""
+    spine = ax.spines[spine_key]
+    ax_frame_on = ax.get_frame_on()
+    spine_frame_like = spine.is_frame_like()
+    if not spine.get_visible():
+        return False
+    elif not spine._edgecolor[-1]:  # user's may have set edgecolor alpha==0
+        return False
+    elif not ax_frame_on and spine_frame_like:
+        return False
+    elif ax_frame_on and spine_frame_like:
+        return True
+    elif not ax_frame_on and not spine_frame_like:
+        return True  # we've already checked for that it's visible.
+    else:
+        return False # oh man, and i thought we exhausted the options...
+
 
 def is_bar(**props):
     """A test to decide whether a path is a bar from a vertical bar chart."""
diff --git a/plotly/matplotlylib/renderer.py b/plotly/matplotlylib/renderer.py
index 1f1feeccc..10bfa7479 100644
--- a/plotly/matplotlylib/renderer.py
+++ b/plotly/matplotlylib/renderer.py
@@ -133,14 +133,10 @@ class PlotlyRenderer(Renderer):
         xaxis = XAxis(
             anchor='y{}'.format(self.axis_ct),
             zeroline=False,
-            showline=True,
-            mirror='ticks',
             ticks='inside')
         yaxis = YAxis(
             anchor='x{}'.format(self.axis_ct),
             zeroline=False,
-            showline=True,
-            mirror='ticks',
             ticks='inside')
         # update defaults with things set in mpl
         mpl_xaxis, mpl_yaxis = mpltools.prep_xy_axis(ax=ax,
@@ -149,6 +145,16 @@ class PlotlyRenderer(Renderer):
                                                      y_bounds=self.mpl_y_bounds)
         xaxis.update(mpl_xaxis)
         yaxis.update(mpl_yaxis)
+        bottom_spine = mpltools.get_spine_visible(ax, 'bottom')
+        top_spine = mpltools.get_spine_visible(ax, 'top')
+        left_spine = mpltools.get_spine_visible(ax, 'left')
+        right_spine = mpltools.get_spine_visible(ax, 'right')
+        xaxis['mirror'] = mpltools.get_axis_mirror(bottom_spine, top_spine)
+        yaxis['mirror'] = mpltools.get_axis_mirror(left_spine, right_spine)
+        xaxis['showline'] = bottom_spine
+        yaxis['showline'] = top_spine
+
+
         # put axes in our figure
         self.plotly_fig['layout']['xaxis{}'.format(self.axis_ct)] = xaxis
         self.plotly_fig['layout']['yaxis{}'.format(self.axis_ct)] = yaxis
['plotly/matplotlylib/renderer.py', 'plotly/matplotlylib/mpltools.py']