Backport PR #12507: FIX: make minor ticks formatted with science formatter as well (#12517)

meeseeksmachine · timhoffm · commit a5ecb156e15d · 2018-10-13T16:53:26.000+02:00
diff --git a/lib/matplotlib/colorbar.py b/lib/matplotlib/colorbar.py
@@ -235,12 +235,12 @@ def __init__(self, colorbar):
         self._colorbar = colorbar
         nbins = 'auto'
         steps = [1, 2, 2.5, 5, 10]
-        ticker.MaxNLocator.__init__(self, nbins=nbins, steps=steps)
+        super().__init__(nbins=nbins, steps=steps)
 
     def tick_values(self, vmin, vmax):
         vmin = max(vmin, self._colorbar.norm.vmin)
         vmax = min(vmax, self._colorbar.norm.vmax)
-        ticks = ticker.MaxNLocator.tick_values(self, vmin, vmax)
+        ticks = super().tick_values(vmin, vmax)
         return ticks[(ticks >= vmin) & (ticks <= vmax)]
 
 
@@ -261,12 +261,12 @@ def __init__(self, colorbar, n=None):
         """
         self._colorbar = colorbar
         self.ndivs = n
-        ticker.AutoMinorLocator.__init__(self, n=None)
+        super().__init__(n=None)
 
     def __call__(self):
         vmin = self._colorbar.norm.vmin
         vmax = self._colorbar.norm.vmax
-        ticks = ticker.AutoMinorLocator.__call__(self)
+        ticks = super().__call__()
         rtol = (vmax - vmin) * 1e-10
         return ticks[(ticks >= vmin - rtol) & (ticks <= vmax + rtol)]
 
@@ -291,12 +291,12 @@ def __init__(self, colorbar, *args, **kwargs):
         same as `~.ticker.LogLocator`.
         """
         self._colorbar = colorbar
-        ticker.LogLocator.__init__(self, *args, **kwargs)
+        super().__init__(*args, **kwargs)
 
     def tick_values(self, vmin, vmax):
         vmin = self._colorbar.norm.vmin
         vmax = self._colorbar.norm.vmax
-        ticks = ticker.LogLocator.tick_values(self, vmin, vmax)
+        ticks = super().tick_values(vmin, vmax)
         return ticks[(ticks >= vmin) & (ticks <= vmax)]
 
 
@@ -462,7 +462,6 @@ def config_axis(self):
         long_axis.set_ticks_position(self.ticklocation)
         short_axis.set_ticks([])
         short_axis.set_ticks([], minor=True)
-
         self._set_label()
 
     def _get_ticker_locator_formatter(self):
@@ -537,7 +536,7 @@ def update_ticks(self):
                 long_axis.set_minor_locator(_ColorbarLogLocator(self,
                             base=10., subs='auto'))
                 long_axis.set_minor_formatter(
-                    ticker.LogFormatter()
+                    ticker.LogFormatterSciNotation()
                 )
         else:
             _log.debug('Using fixed locator on colorbar')
diff --git a/lib/matplotlib/tests/test_colorbar.py b/lib/matplotlib/tests/test_colorbar.py
@@ -396,3 +396,18 @@ def test_colorbar_axes_kw():
     plt.imshow(([[1, 2], [3, 4]]))
     plt.colorbar(orientation='horizontal', fraction=0.2, pad=0.2, shrink=0.5,
                  aspect=10, anchor=(0., 0.), panchor=(0., 1.))
+
+
+def test_colorbar_log_minortick_labels():
+    with rc_context({'_internal.classic_mode': False}):
+        fig, ax = plt.subplots()
+        pcm = ax.imshow([[10000, 50000]], norm=LogNorm())
+        cb = fig.colorbar(pcm)
+        fig.canvas.draw()
+        lb = cb.ax.yaxis.get_ticklabels(which='both')
+        expected = [r'$\mathdefault{10^{4}}$',
+                    r'$\mathdefault{2\times10^{4}}$',
+                    r'$\mathdefault{3\times10^{4}}$',
+                    r'$\mathdefault{4\times10^{4}}$']
+        for l, exp in zip(lb, expected):
+            assert l.get_text() == exp
