Fixes matplotlib#7742 - axhline rescale issue

sughandj · sughandj · commit 7cf097d78846 · 2017-03-06T21:48:39.000-05:00
Modified axhline() function to save state of ignoring limits and restore after plotting the line
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -724,8 +724,12 @@ def axhline(self, y=0, xmin=0, xmax=1, **kwargs):
 
         trans = self.get_yaxis_transform(which='grid')
         l = mlines.Line2D([xmin, xmax], [y, y], transform=trans, **kwargs)
+
+        # Save state for ignoring existing data limits and set it back later
+        ignore = self.ignore_existing_data_limits
         self.add_line(l)
         self.autoscale_view(scalex=False, scaley=scaley)
+        self.ignore_existing_data_limits = ignore
         return l
 
     @docstring.dedent_interpd
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -4972,3 +4972,32 @@ def test_bar_single_height():
     ax.bar(range(4), 1)
     # Check that a horizontal chart with one width works
     ax.bar(0, 1, bottom=range(4), width=1, orientation='horizontal')
+
+
+def test_axhline_datetime_limits():
+    # Plot horizontal line with other lines in
+    # different order and check if they have the same limits
+    date1 = datetime.datetime(2016, 1, 1, 0, 0, 0)
+    date2 = datetime.datetime(2016, 1, 30, 0, 0, 0)
+    date3 = datetime.datetime(2016, 1, 10, 0, 0, 0)
+
+    dates1 = [date1, date2]
+    values1 = [1, 2]
+
+    dates2 = [date1, date3]
+    values2 = [0, 5]
+
+    fig, (ax1, ax2) = plt.subplots(2, 1)
+
+    ax1.axhline(1.5)
+    ax1.plot(dates1, values1)
+
+    ax2.plot(dates1, values1)
+    ax2.axhline(1.5)
+
+    assert ax1.get_xlim() == ax2.get_xlim()
+
+    ax1.plot(dates2, values2)
+    ax2.plot(dates2, values2)
+
+    assert ax1.get_xlim() == ax2.get_xlim()
