Merge pull request #12681 from meeseeksmachine/auto-backport-of-pr-12656-on-v3.0.x

dstansby · web-flow · commit bfeb569d58a5 · 2018-10-31T09:44:14.000+01:00
Backport PR #12656 on branch v3.0.x (FIX: fix error in colorbar.get_ticks not having valid data)
diff --git a/lib/matplotlib/colorbar.py b/lib/matplotlib/colorbar.py
@@ -387,6 +387,7 @@ def __init__(self, ax, cmap=None,
         self.outline = None
         self.patch = None
         self.dividers = None
+        self._manual_tick_data_values = None
 
         if ticklocation == 'auto':
             ticklocation = 'bottom' if orientation == 'horizontal' else 'right'
@@ -574,7 +575,17 @@ def set_ticks(self, ticks, update_ticks=True):
 
     def get_ticks(self, minor=False):
         """Return the x ticks as a list of locations"""
-        return self._tick_data_values
+        if self._manual_tick_data_values is None:
+            ax = self.ax
+            if self.orientation == 'vertical':
+                long_axis, short_axis = ax.yaxis, ax.xaxis
+            else:
+                long_axis, short_axis = ax.xaxis, ax.yaxis
+            return long_axis.get_majorticklocs()
+        else:
+            # We made the axes manually, the old way, and the ylim is 0-1,
+            # so the majorticklocs are in those units, not data units.
+            return self._manual_tick_data_values
 
     def set_ticklabels(self, ticklabels, update_ticks=True):
         """
@@ -756,7 +767,7 @@ def _ticker(self, locator, formatter):
         else:
             eps = (intv[1] - intv[0]) * 1e-10
             b = b[(b <= intv[1] + eps) & (b >= intv[0] - eps)]
-        self._tick_data_values = b
+        self._manual_tick_data_values = b
         ticks = self._locate(b)
         formatter.set_locs(b)
         ticklabels = [formatter(t, i) for i, t in enumerate(b)]
diff --git a/lib/matplotlib/tests/test_colorbar.py b/lib/matplotlib/tests/test_colorbar.py
@@ -436,3 +436,13 @@ def test_colorbar_renorm():
     cbar.update_normal(im)
     assert np.isclose(cbar.vmin, z.min() * 1000)
     assert np.isclose(cbar.vmax, z.max() * 1000)
+
+
+def test_colorbar_get_ticks():
+    with rc_context({'_internal.classic_mode': False}):
+
+        fig, ax = plt. subplots()
+        np.random.seed(19680801)
+        pc = ax.pcolormesh(np.random.rand(30, 30))
+        cb = fig.colorbar(pc)
+        np.testing.assert_allclose(cb.get_ticks(), [0.2, 0.4, 0.6, 0.8])
