Backport PR #15478: Make ConciseDateFormatter obey timezone

tacaswell · MeeseeksDev[bot] · commit 1ea831785c44 · 2019-11-01T19:49:20.000Z
diff --git a/lib/matplotlib/dates.py b/lib/matplotlib/dates.py
@@ -769,7 +769,7 @@ def __call__(self, x, pos=None):
         return formatter(x, pos=pos)
 
     def format_ticks(self, values):
-        tickdatetime = [num2date(value) for value in values]
+        tickdatetime = [num2date(value, tz=self._tz) for value in values]
         tickdate = np.array([tdt.timetuple()[:6] for tdt in tickdatetime])
 
         # basic algorithm:
@@ -835,7 +835,7 @@ def get_offset(self):
         return self.offset_string
 
     def format_data_short(self, value):
-        return num2date(value).strftime('%Y-%m-%d %H:%M:%S')
+        return num2date(value, tz=self._tz).strftime('%Y-%m-%d %H:%M:%S')
 
 
 class AutoDateFormatter(ticker.Formatter):
diff --git a/lib/matplotlib/tests/test_dates.py b/lib/matplotlib/tests/test_dates.py
@@ -512,6 +512,49 @@ def _create_auto_date_locator(date1, date2):
         assert strings == expected
 
 
+def test_concise_formatter_tz():
+    def _create_auto_date_locator(date1, date2, tz):
+        fig, ax = plt.subplots()
+
+        locator = mdates.AutoDateLocator(interval_multiples=True)
+        formatter = mdates.ConciseDateFormatter(locator, tz=tz)
+        ax.yaxis.set_major_locator(locator)
+        ax.yaxis.set_major_formatter(formatter)
+        ax.set_ylim(date1, date2)
+        fig.canvas.draw()
+        sts = []
+        for st in ax.get_yticklabels():
+            sts += [st.get_text()]
+        return sts, ax.yaxis.get_offset_text().get_text()
+
+    d1 = datetime.datetime(1997, 1, 1).replace(tzinfo=datetime.timezone.utc)
+    results = ([datetime.timedelta(hours=40),
+                ['03:00', '07:00', '11:00', '15:00', '19:00', '23:00',
+                 '03:00', '07:00', '11:00', '15:00', '19:00'],
+                "1997-Jan-02"
+                ],
+               [datetime.timedelta(minutes=20),
+                ['03:00', '03:05', '03:10', '03:15', '03:20'],
+                "1997-Jan-01"
+                ],
+               [datetime.timedelta(seconds=40),
+                ['03:00', '05', '10', '15', '20', '25', '30', '35', '40'],
+                "1997-Jan-01 03:00"
+                ],
+               [datetime.timedelta(seconds=2),
+                ['59.5', '03:00', '00.5', '01.0', '01.5', '02.0', '02.5'],
+                "1997-Jan-01 03:00"
+                ],
+               )
+
+    new_tz = datetime.timezone(datetime.timedelta(hours=3))
+    for t_delta, expected_strings, expected_offset in results:
+        d2 = d1 + t_delta
+        strings, offset = _create_auto_date_locator(d1, d2, new_tz)
+        assert strings == expected_strings
+        assert offset == expected_offset
+
+
 def test_auto_date_locator_intmult_tz():
     def _create_auto_date_locator(date1, date2, tz):
         locator = mdates.AutoDateLocator(interval_multiples=True, tz=tz)
