Add a new kwarg to the image_comparison decorator, remove_text, which…

… removes titles and ticks from a figure before comparison. Use this throughout to make more of the tests less dependent on text differences.

lib/matplotlib/testing/decorators.py

@@ -6,6 +6,7 @@
 import matplotlib
 import matplotlib.tests
 import matplotlib.units
+from matplotlib import ticker
 from matplotlib import pyplot as plt
 from matplotlib import ft2font
 import numpy as np
@@ -99,6 +100,16 @@ def setup_class(cls):
 
         cls._func()
 
+    @staticmethod
+    def remove_text(figure):
+        figure.suptitle("")
+        for ax in figure.get_axes():
+            ax.set_title("")
+            ax.xaxis.set_major_formatter(ticker.NullFormatter())
+            ax.xaxis.set_minor_formatter(ticker.NullFormatter())
+            ax.yaxis.set_major_formatter(ticker.NullFormatter())
+            ax.yaxis.set_minor_formatter(ticker.NullFormatter())
+
     def test(self):
         baseline_dir, result_dir = _image_directories(self._func)
 
@@ -128,6 +139,9 @@ def test(self):
                     will_fail, fail_msg,
                     known_exception_class=ImageComparisonFailure)
                 def do_test():
+                    if self._remove_text:
+                        self.remove_text(figure)
+
                     figure.savefig(actual_fname)
 
                     err = compare_images(expected_fname, actual_fname,
@@ -151,7 +165,8 @@ def do_test():
 
                 yield (do_test,)
 
-def image_comparison(baseline_images=None, extensions=None, tol=1e-3, freetype_version=None):
+def image_comparison(baseline_images=None, extensions=None, tol=1e-3,
+                     freetype_version=None, remove_text=False):
     """
     call signature::
 
@@ -179,6 +194,11 @@ def image_comparison(baseline_images=None, extensions=None, tol=1e-3, freetype_v
       *freetype_version*: str or tuple
         The expected freetype version or range of versions for this
         test to pass.
+
+      *remove_text*: bool
+        Remove the title and tick text from the figure before
+        comparison.  This does not remove other, more deliberate,
+        text, such as legends and annotations.
     """
 
     if baseline_images is None:
@@ -210,7 +230,8 @@ def compare_images_decorator(func):
              '_baseline_images': baseline_images,
              '_extensions': extensions,
              '_tol': tol,
-             '_freetype_version': freetype_version})
+             '_freetype_version': freetype_version,
+             '_remove_text': remove_text})
 
         return new_class
     return compare_images_decorator
@@ -242,4 +263,3 @@ def _image_directories(func):
         os.makedirs(result_dir)
 
     return baseline_dir, result_dir
-