use scalars below a min exponent in LogFormatterMathtext

zblz · zblz · commit dc6194079c31 · 2016-08-23T09:54:00.000+01:00
diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
@@ -1083,6 +1083,7 @@ 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
@@ -304,6 +304,20 @@ 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 test_LogFormatterSciNotation():
     test_cases = {
diff --git a/lib/matplotlib/ticker.py b/lib/matplotlib/ticker.py
@@ -1007,6 +1007,7 @@ 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:
@@ -1019,6 +1020,8 @@ def __call__(self, x, pos=None):
         is_decade = is_close_to_int(fx)
         exponent = np.round(fx) if is_decade else np.floor(fx)
         coeff = np.round(x / b ** exponent)
+        if is_decade:
+            fx = nearest_long(fx)
 
         sign_string = '-' if x < 0 else ''
 
@@ -1031,6 +1034,12 @@ def __call__(self, x, pos=None):
         if coeff in self.sublabel:
             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:
                 return self._non_decade_format(sign_string, base, fx, usetex)
             else:
diff --git a/matplotlibrc.template b/matplotlibrc.template
@@ -314,6 +314,7 @@ 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
