prevent subticks from being added to center zero label

Raab70 · Raab70 · commit b26b59848ead · 2017-12-30T09:22:08.000-06:00
diff --git a/lib/matplotlib/ticker.py b/lib/matplotlib/ticker.py
@@ -1063,6 +1063,7 @@ class LogFormatterMathtext(LogFormatter):
     """
     Format values for log axis using ``exponent = log_base(value)``.
     """
+    _min_zero_pos = None
 
     def _non_decade_format(self, sign_string, base, fx, usetex):
         'Return string for non-decade locations'
@@ -1076,16 +1077,21 @@ def __call__(self, x, pos=None):
         """
         Return the format for tick value `x`.
 
-        The position `pos` is ignored.
+        The position `pos` is used for SymLogNorm for ensuring
+        only one zero entry is present.
         """
         usetex = rcParams['text.usetex']
         min_exp = rcParams['axes.formatter.min_exponent']
 
         if x == 0:  # Symlog
-            if usetex:
-                return '$0$'
+            if self._min_zero_pos is None:
+                self._min_zero_pos = pos
+                if usetex:
+                    return '$0$'
+                else:
+                    return '$%s$' % _mathdefault('0')
             else:
-                return '$%s$' % _mathdefault('0')
+                return ''
 
         sign_string = '-' if x < 0 else ''
         x = abs(x)
@@ -2315,7 +2321,7 @@ def get_log_range(lo, hi):
 
         if has_c:
             if has_b:
-                c_range = get_log_range(t, vmax + 1)
+                c_range = get_log_range(t, vmax + 1)  # Why the +1?
             else:
                 c_range = get_log_range(vmin, vmax + 1)
         else:
@@ -2346,7 +2352,10 @@ def get_log_range(lo, hi):
         if len(subs) > 1 or subs[0] != 1.0:
             ticklocs = []
             for decade in decades:
-                ticklocs.extend(subs * decade)
+                if decade == 0:
+                    ticklocs.append(decade)
+                else:
+                    ticklocs.extend(subs * decade)
         else:
             ticklocs = decades
 
