Use fix_minus in format_data_short.

anntzer · anntzer · commit 8c4df3864386 · 2019-09-05T15:49:39.000+02:00
See changelog.  AFAICS, all GUI toolkits (at least qt5/gtk3/wx/tk)
display the unicode minus properly.

Moving the implementation of the replacement to the base Formatter class
is because it is otherwise confusing as to whether `self.fix_minus`
does the replacement or not -- one needs to check whether the current
class overrides the do-nothing fix_minus.  Instead, one can just have a
base-class implementation that performs the replacement, and not call
`self.fix_minus` if the replacement is not desired.

For example, LogFormatter.fix_minus used to do nothing; there are tests
that check that.  Just don't call fix_minus instead.
diff --git a/doc/api/next_api_changes/2019-08-01-AL.rst b/doc/api/next_api_changes/2019-08-01-AL.rst
@@ -0,0 +1,10 @@
+API changes
+```````````
+
+`.Formatter.fix_minus` now performs hyphen-to-unicode-minus replacement
+whenever :rc:`axes.unicode_minus` is True; i.e. its behavior matches the one
+of ``.ScalarFormatter.fix_minus`` (`.ScalarFormatter` now just inherits that
+implementation).
+
+This replacement is now used by the ``format_data_short`` method of the various
+builtin formatter classes, which affects the cursor value in the GUI toolbars.
diff --git a/lib/matplotlib/tests/test_ticker.py b/lib/matplotlib/tests/test_ticker.py
@@ -455,6 +455,14 @@ class TestScalarFormatter:
         (True, (6, 6), (-1e5, 1e5), 6, False),
     ]
 
+    @pytest.mark.parametrize('unicode_minus, result',
+                             [(True, "\N{MINUS SIGN}1"), (False, "-1")])
+    def test_unicode_minus(self, unicode_minus, result):
+        matplotlib.rcParams['axes.unicode_minus'] = unicode_minus
+        assert (
+            plt.gca().xaxis.get_major_formatter().format_data_short(-1).strip()
+            == result)
+
     @pytest.mark.parametrize('left, right, offset', offset_data)
     def test_offset_value(self, left, right, offset):
         fig, ax = plt.subplots()
diff --git a/lib/matplotlib/ticker.py b/lib/matplotlib/ticker.py
@@ -280,21 +280,23 @@ def get_offset(self):
     def set_locs(self, locs):
         self.locs = locs
 
-    def fix_minus(self, s):
-        """
-        Some classes may want to replace a hyphen for minus with the
-        proper unicode symbol (U+2212) for typographical correctness.
-        The default is to not replace it.
-
-        Note, if you use this method, e.g., in :meth:`format_data` or
-        call, you probably don't want to use it for
-        :meth:`format_data_short` since the toolbar uses this for
-        interactive coord reporting and I doubt we can expect GUIs
-        across platforms will handle the unicode correctly.  So for
-        now the classes that override :meth:`fix_minus` should have an
-        explicit :meth:`format_data_short` method
-        """
-        return s
+    @staticmethod
+    def fix_minus(s):
+        """
+        Some classes may want to replace a hyphen for minus with the proper
+        unicode symbol (U+2212) for typographical correctness.  This is a
+        helper method to perform such a replacement when it is enabled via
+        :rc:`axes.unicode_minus`.
+        """
+        # Additionally, we disable the replacement when using usetex without
+        # unicode support (this is deprecated, i.e., in a future version,
+        # unicode support will always be enabled).
+        if (rcParams['axes.unicode_minus']
+                and (rcParams['text.latex.unicode']
+                     or not rcParams['text.usetex'])):
+            return s.replace('-', '\N{MINUS SIGN}')
+        else:
+            return s
 
     def _set_locator(self, locator):
         """Subclasses may want to override this to set a locator."""
@@ -565,15 +567,6 @@ def set_useMathText(self, val):
 
     useMathText = property(fget=get_useMathText, fset=set_useMathText)
 
-    def fix_minus(self, s):
-        """
-        Replace hyphens with a unicode minus.
-        """
-        if rcParams['text.usetex'] or not rcParams['axes.unicode_minus']:
-            return s
-        else:
-            return s.replace('-', '\N{MINUS SIGN}')
-
     def __call__(self, x, pos=None):
         """
         Return the format for tick value *x* at position *pos*.
@@ -624,15 +617,12 @@ def set_powerlimits(self, lims):
         self._powerlimits = lims
 
     def format_data_short(self, value):
-        """
-        Return a short formatted string representation of a number.
-        """
-        if self._useLocale:
-            return locale.format_string('%-12g', (value,))
-        elif isinstance(value, np.ma.MaskedArray) and value.mask:
-            return ''
-        else:
-            return '%-12g' % value
+        # docstring inherited
+        return (
+            "" if isinstance(value, np.ma.MaskedArray) and value.mask else
+            self.fix_minus(
+                locale.format_string("%-12g", (value,)) if self._useLocale else
+                "%-12g" % value))
 
     def format_data(self, value):
         """
@@ -1026,7 +1016,7 @@ def __call__(self, x, pos=None):
         vmin, vmax = self.axis.get_view_interval()
         vmin, vmax = mtransforms.nonsingular(vmin, vmax, expander=0.05)
         s = self._num_to_string(x, vmin, vmax)
-        return self.fix_minus(s)
+        return s
 
     def format_data(self, value):
         b = self.labelOnlyBase
@@ -1036,9 +1026,7 @@ def format_data(self, value):
         return value
 
     def format_data_short(self, value):
-        """
-        Return a short formatted string representation of a number.
-        """
+        # docstring inherited
         return '%-12g' % value
 
     @cbook.deprecated("3.1")
@@ -1462,12 +1450,6 @@ def set_useMathText(self, val):
 
     useMathText = property(fget=get_useMathText, fset=set_useMathText)
 
-    def fix_minus(self, s):
-        """
-        Replace hyphens with a unicode minus.
-        """
-        return ScalarFormatter.fix_minus(self, s)
-
     def __call__(self, x, pos=None):
         s = "%s%s" % (self.format_eng(x), self.unit)
         # Remove the trailing separator when there is neither prefix nor unit
