Merge pull request matplotlib#22140 from QuLogic/log-minus

Ensure log formatters use Unicode minus

Author: dstansby

lib/matplotlib/tests/baseline_images/test_axes/errorbar_mixed.pdf

@@ -2545,6 +2545,9 @@ def test_pyplot_axes():
 
 @image_comparison(['log_scales'])
 def test_log_scales():
+    # Remove this if regenerating the image.
+    plt.rcParams['axes.unicode_minus'] = False
+
     fig, ax = plt.subplots()
     ax.plot(np.log(np.linspace(0.1, 100)))
     ax.set_yscale('log', base=5.5)

lib/matplotlib/tests/baseline_images/test_axes/errorbar_mixed.png

@@ -577,7 +577,7 @@ def test_colorbar_format(fmt):
     im.set_norm(LogNorm(vmin=0.1, vmax=10))
     fig.canvas.draw()
     assert (cbar.ax.yaxis.get_ticklabels()[0].get_text() ==
-            r'$\mathdefault{10^{-2}}$')
+            '$\\mathdefault{10^{\N{Minus Sign}2}}$')
 
 
 def test_colorbar_scale_reset():

lib/matplotlib/tests/baseline_images/test_axes/errorbar_mixed.svg

@@ -637,6 +637,7 @@ def test_basic(self, labelOnlyBase, base, exponent, locs, positions,
         formatter.axis = FakeAxis(1, base**exponent)
         vals = base**locs
         labels = [formatter(x, pos) for (x, pos) in zip(vals, positions)]
+        expected = [label.replace('-', '\N{Minus Sign}') for label in expected]
         assert labels == expected
 
     def test_blank(self):
@@ -662,7 +663,7 @@ class TestLogFormatterMathtext:
     @pytest.mark.parametrize('min_exponent, value, expected', test_data)
     def test_min_exponent(self, min_exponent, value, expected):
         with mpl.rc_context({'axes.formatter.min_exponent': min_exponent}):
-            assert self.fmt(value) == expected
+            assert self.fmt(value) == expected.replace('-', '\N{Minus Sign}')
 
 
 class TestLogFormatterSciNotation:
@@ -691,7 +692,7 @@ def test_basic(self, base, value, expected):
         formatter = mticker.LogFormatterSciNotation(base=base)
         formatter.sublabel = {1, 2, 5, 1.2}
         with mpl.rc_context({'text.usetex': False}):
-            assert formatter(value) == expected
+            assert formatter(value) == expected.replace('-', '\N{Minus Sign}')
 
 
 class TestLogFormatter:
@@ -907,19 +908,21 @@ def logit_deformatter(string):
         float 1.41e-4, as '0.5' or as r'$\mathdefault{\frac{1}{2}}$' in float
         0.5,
         """
+        # Can inline the Unicode escapes to the raw strings in Python 3.8+
         match = re.match(
             r"[^\d]*"
-            r"(?P<comp>1-)?"
+            r"(?P<comp>1" "[-\N{Minus Sign}]" r")?"
             r"(?P<mant>\d*\.?\d*)?"
             r"(?:\\cdot)?"
-            r"(?:10\^\{(?P<expo>-?\d*)})?"
+            r"(?:10\^\{(?P<expo>" "[-\N{Minus Sign}]" r"?\d*)})?"
             r"[^\d]*$",
             string,
         )
         if match:
             comp = match["comp"] is not None
             mantissa = float(match["mant"]) if match["mant"] else 1
-            expo = int(match["expo"]) if match["expo"] is not None else 0
+            expo = (int(match["expo"].replace("\N{Minus Sign}", "-"))
+                    if match["expo"] is not None else 0)
             value = mantissa * 10 ** expo
             if match["mant"] or match["expo"] is not None:
                 if comp:
@@ -1044,8 +1047,8 @@ def test_use_overline(self):
         Test the parameter use_overline
         """
         x = 1 - 1e-2
-        fx1 = r"$\mathdefault{1-10^{-2}}$"
-        fx2 = r"$\mathdefault{\overline{10^{-2}}}$"
+        fx1 = "$\\mathdefault{1\N{Minus Sign}10^{\N{Minus Sign}2}}$"
+        fx2 = "$\\mathdefault{\\overline{10^{\N{Minus Sign}2}}}$"
         form = mticker.LogitFormatter(use_overline=False)
         assert form(x) == fx1
         form.use_overline(True)

lib/matplotlib/tests/test_axes.py

@@ -1000,7 +1000,7 @@ 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 s
+        return self.fix_minus(s)
 
     def format_data(self, value):
         with cbook._setattr_cm(self, labelOnlyBase=False):
@@ -1090,11 +1090,12 @@ def __call__(self, x, pos=None):
             base = '%s' % b
 
         if abs(fx) < min_exp:
-            return r'$\mathdefault{%s%g}$' % (sign_string, x)
+            s = r'$\mathdefault{%s%g}$' % (sign_string, x)
         elif not is_x_decade:
-            return self._non_decade_format(sign_string, base, fx, usetex)
+            s = self._non_decade_format(sign_string, base, fx, usetex)
         else:
-            return r'$\mathdefault{%s%s^{%d}}$' % (sign_string, base, fx)
+            s = r'$\mathdefault{%s%s^{%d}}$' % (sign_string, base, fx)
+        return self.fix_minus(s)
 
 
 class LogFormatterSciNotation(LogFormatterMathtext):
@@ -1296,7 +1297,7 @@ def __call__(self, x, pos=None):
             s = self._one_minus(self._format_value(1-x, 1-self.locs))
         else:
             s = self._format_value(x, self.locs, sci_notation=False)
-        return r"$\mathdefault{%s}$" % s
+        return r"$\mathdefault{%s}$" % self.fix_minus(s)
 
     def format_data_short(self, value):
         # docstring inherited