use scalars below a min exponent in LogFormatterMathtext

zblz · zblz · commit a6b5299336a1 · 2016-07-26T08:57:25.000+01:00
diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
@@ -1082,6 +1082,7 @@ def validate_animation_writer_path(p):
     'axes.formatter.use_locale': [False, validate_bool],
                                # Use the current locale to format ticks
     'axes.formatter.use_mathtext': [False, validate_bool],
+    'axes.formatter.min_exponent': [0, validate_int],  # minimum exponent to format in scientific notation
     'axes.formatter.useoffset': [True, validate_bool],
     'axes.unicode_minus': [True, validate_bool],
     'axes.color_cycle': [
diff --git a/lib/matplotlib/tests/test_ticker.py b/lib/matplotlib/tests/test_ticker.py
@@ -251,6 +251,20 @@ def get_view_interval(self):
         formatter.axis = FakeAxis(1, base**50)
         yield _logfe_helper, formatter, base, locs, i, expected_result
 
+def test_LogFormatterMathtext_min_exponent():
+    fmt = mticker.LogFormatterMathtext()
+
+    with matplotlib.rc_context({'axes.formatter.min_exponent': 0}):
+        assert fmt(1) == '${10^{0}}$'
+        assert fmt(1e-2) == '${10^{-2}}$'
+        assert fmt(1e2) == '${10^{2}}$'
+
+    with matplotlib.rc_context({'axes.formatter.min_exponent': 3}):
+        assert fmt(1) == '${1}$'
+        assert fmt(1e-2) == '${0.01}$'
+        assert fmt(1e2) == '${100}$'
+        assert fmt(1e-3) == '${10^{-3}}$'
+        assert fmt(1e3) == '${10^{3}}$'
 
 def _pprint_helper(value, domain, expected):
     fmt = mticker.LogFormatter()
diff --git a/lib/matplotlib/ticker.py b/lib/matplotlib/ticker.py
@@ -959,6 +959,7 @@ def __call__(self, x, pos=None):
         """
         b = self._base
         usetex = rcParams['text.usetex']
+        min_exp = rcParams['axes.formatter.min_exponent']
 
         # only label the decades
         if x == 0:
@@ -969,6 +970,8 @@ def __call__(self, x, pos=None):
 
         fx = math.log(abs(x)) / math.log(b)
         is_decade = is_close_to_int(fx)
+        if is_decade:
+            fx = nearest_long(fx)
 
         sign_string = '-' if x < 0 else ''
 
@@ -980,6 +983,12 @@ def __call__(self, x, pos=None):
 
         if not is_decade and self.labelOnlyBase:
             return ''
+        elif np.abs(fx) < min_exp:
+            if usetex:
+                return r'${0}{1:g}$'.format(sign_string, x)
+            else:
+                return '${0}$'.format(_mathdefault(
+                    '{0}{1:g}'.format(sign_string, x)))
         elif not is_decade:
             if usetex:
                 return (r'$%s%s^{%.2f}$') % \
diff --git a/matplotlibrc.template b/matplotlibrc.template
@@ -315,6 +315,7 @@ backend      : $TEMPLATE_BACKEND
                                    # separator in the fr_FR locale.
 #axes.formatter.use_mathtext : False # When True, use mathtext for scientific
                                      # notation.
+#axes.formatter.min_exponent: 0 # minimum exponent to format in scientific notation
 #axes.formatter.useoffset      : True    # If True, the tick label formatter
                                          # will default to labeling ticks relative
                                          # to an offset when the data range is very
