Merge pull request #10129 from Raab70/bug-fix/logsymnorm-zero-labels

dstansby · web-flow · commit a1e9db1212b5 · 2018-01-04T20:02:56.000Z
Fix multiple zero labels when using SymLogNorm
diff --git a/lib/matplotlib/tests/test_colors.py b/lib/matplotlib/tests/test_colors.py
@@ -247,6 +247,18 @@ def test_SymLogNorm_colorbar():
     plt.close(fig)
 
 
+def test_SymLogNorm_single_zero():
+    """
+    Test SymLogNorm to ensure it is not adding sub-ticks to zero label
+    """
+    fig = plt.figure()
+    norm = mcolors.SymLogNorm(1e-5, vmin=-1, vmax=1)
+    cbar = mcolorbar.ColorbarBase(fig.add_subplot(111), norm=norm)
+    ticks = cbar.get_ticks()
+    assert sum(ticks == 0) == 1
+    plt.close(fig)
+
+
 def _inverse_tester(norm_instance, vals):
     """
     Checks if the inverse of the given normalization is working.
diff --git a/lib/matplotlib/ticker.py b/lib/matplotlib/ticker.py
@@ -2346,7 +2346,10 @@ 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
 
