Added an {figure,.pyplot}.encode_as feature to encode a figure as a b…

…ytestring (not writing it to file), which can be practical in combination with the base64-package. Also addded a {figure,pyplot}.subplots_iterator which returns an iterator over subplots, which can be practical in for example ipynb's, where one wants to make many graphs and likes them to be 3 (or 5 or whatever) on a line.
matplotlib · prhbrt · May 11, 2016 · May 11, 2016 · May 11, 2016 · Jul 19, 2016
commit 5a3a8827b685c49853f4bedb9484d8ef4fae9c98
diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
@@ -1513,6 +1513,7 @@ def _jupyter_nbextension_paths():
     'matplotlib.tests.test_streamplot',
     'matplotlib.tests.test_style',
     'matplotlib.tests.test_subplots',
+    'matplotlib.tests.test_subplots_iterator',
     'matplotlib.tests.test_table',
     'matplotlib.tests.test_text',
     'matplotlib.tests.test_texmanager',
@@ -1553,7 +1554,12 @@ def _init_tests():
         warnings.warn(
             "matplotlib is not built with the correct FreeType version to run "
             "tests.  Set local_freetype=True in setup.cfg and rebuild. "
-            "Expect many image comparison failures below.")
+            "Expect many image comparison failures below. "
+            "Expected {0} != found {1}".format(
+                ft2font.__freetype_version__,
+                LOCAL_FREETYPE_VERSION
+            )
+        )
 
     try:
         import nose

diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
@@ -49,6 +49,8 @@
                                    TransformedBbox)
 from matplotlib.backend_bases import NonGuiException
 
+import io
+
 docstring.interpd.update(projection_names=get_projection_names())
 
 
@@ -1082,7 +1084,7 @@ def subplots(self, nrows=1, ncols=1, sharex=False, sharey=False,
         --------
         pyplot.subplots : pyplot API; docstring includes examples.
         """
-
+        
         # for backwards compatibility
         if isinstance(sharex, bool):
             sharex = "all" if sharex else "none"
@@ -1144,6 +1146,29 @@ def subplots(self, nrows=1, ncols=1, sharex=False, sharey=False,
             # Returned axis array will be always 2-d, even if nrows=ncols=1.
             return axarr
 
+
+    def subplots_iterator(self, nrows=1, ncols=1, show_in_between=False,
+                          sharex=False, sharey=False, squeeze=True,
+                          subplot_kw=None, gridspec_kw=None):
+        """ Iteratively yields the axis object of a rows x cols subplot and creates new subplots when needed"""
+        while True:
+            axes = self.subplots(
+                nrows=nrows,
+                ncols=ncols,
+                sharex=sharex,
+                sharey=sharey,
+                squeeze=False,
+                subplot_kw=subplot_kw,
+                gridspec_kw=gridspec_kw
+            )
+            assert axes.shape == (nrows, ncols), "Matplotlib panic: the returned shape of subplots() is not what was expected: {0} != {1}".format(axes.shape, (nrows, ncols))
+            for row in range(nrows):
+                for col in range(ncols):
+                    yield axes[row, col]
+            if show_in_between:
+                self.show(block=False)
+
+
     def __remove_ax(self, ax):
         def _reset_loc_form(axis):
             axis.set_major_formatter(axis.get_major_formatter())
@@ -1673,6 +1698,17 @@ def savefig(self, *args, **kwargs):
                 ax.patch.set_facecolor(cc[0])
                 ax.patch.set_edgecolor(cc[1])
 
+    def encode_as(self, **kwargs):
+        """ Equivalent of savefig, but does not store to a file, but returns a bytestring
+        using io.BytesIO. All kwargs are passed to savefig."""
+        assert 'format' in kwargs, "Make sure to specify the format"
+        assert 'fname' not in kwargs, "Do not provide a filename, this method returns a bytestring and does not write to a file"
+
+        in_memory_file = io.BytesIO()
+        self.savefig(in_memory_file, **kwargs)
+        in_memory_file.seek(0)
+        return in_memory_file.getvalue()
+
     @docstring.dedent_interpd
     def colorbar(self, mappable, cax=None, ax=None, use_gridspec=True, **kw):
         """

diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
@@ -21,6 +21,7 @@
 from matplotlib.externals import six
 
 import sys
+import io
 import warnings
 import types
 
@@ -688,6 +689,18 @@ def savefig(*args, **kwargs):
     return res
 
 
+
+def encode_as(**kwargs):
+    """ Equivalent of savefig, but does not store to a file, but returns a bytestring
+    using io.BytesIO. All kwargs are passed to savefig."""
+    assert 'format' in kwargs, "Make sure to specify the format"
+    assert 'fname' not in kwargs, "Do not provide a filename, this function returns a bytestring and does not write to a file"
+
+    in_memory_file = io.BytesIO()
+    savefig(in_memory_file, **kwargs)
+    in_memory_file.seek(0)
+    return in_memory_file.getvalue()
+
 @docstring.copy_dedent(Figure.ginput)
 def ginput(*args, **kwargs):
     """
@@ -1146,6 +1159,23 @@ def subplots(nrows=1, ncols=1, sharex=False, sharey=False, squeeze=True,
                        gridspec_kw=gridspec_kw)
     return fig, axs
 
+def subplots_iterator(nrows=1, ncols=1, show_in_between=False, sharex=False,
+                      sharey=False, squeeze=True, subplot_kw=None,
+                      gridspec_kw=None, **fig_kw):
+    """ Iteratively yields the axis object of a rows x cols subplot and creates new subplots when needed"""
+    for axis in (
+        figure(**fig_kw).subplots_iterator(
+            nrows=nrows,
+            ncols=ncols,
+            sharex=sharex,
+            sharey=sharey,
+            squeeze=squeeze,
+            subplot_kw=subplot_kw,
+            gridspec_kw=gridspec_kw
+        )
+    ):
+            yield axis
+
 
 def subplot2grid(shape, loc, rowspan=1, colspan=1, fig=None, **kwargs):
     """

diff --git a/lib/matplotlib/testing/decorators.py b/lib/matplotlib/testing/decorators.py
@@ -232,7 +232,7 @@ def test(self):
                     shutil.copyfile(orig_expected_fname, expected_fname)
                 else:
                     will_fail = True
-                    fail_msg = 'Do not have baseline image %s' % expected_fname
+                    fail_msg = 'Do not have baseline image {0} because this file does not exist: {1}'.format(expected_fname, orig_expected_fname)
 
                 @knownfailureif(
                     will_fail, fail_msg,

diff --git a/lib/matplotlib/tests/__init__.py b/lib/matplotlib/tests/__init__.py
@@ -10,6 +10,7 @@
 
 _multiprocess_can_split_ = True
 
+import pyparsing;
 
 # Check that the test directories exist
 if not os.path.exists(os.path.join(

diff --git a/lib/matplotlib/tests/baseline_images/test_subplots_iterator/subplots_offset_text.pdf b/lib/matplotlib/tests/baseline_images/test_subplots_iterator/subplots_offset_text.pdf
diff --git a/...atplotlib/tests/baseline_images/test_subplots_iterator/subplots_offset_text.png b/...atplotlib/tests/baseline_images/test_subplots_iterator/subplots_offset_text.png