Use auto locator & formater.

With (hopefully) appropriate settings.

apachedex/__init__.py

@@ -52,13 +52,7 @@ except ImportError:
 else:
   matplotlib.use('Agg')
   import matplotlib.pyplot as pyplot
-  from matplotlib.dates import (
-    DateFormatter,
-    DayLocator,
-    HourLocator,
-    AutoDateLocator,
-    AutoDateFormatter,
-  )
+  from matplotlib.dates import AutoDateLocator, AutoDateFormatter
 
 
 MONTH_VALUE_DICT = dict((y, x) for (x, y) in enumerate(('Jan', 'Feb', 'Mar',
@@ -537,17 +531,14 @@ def main():
         daily_data = data.getApdexData()
         date_list = [datetime.strptime(x[0], '%Y/%m/%d' + {'day': ' %H'}.get(
           args.period, '')) for x in daily_data]
-        date_range = date_list[-1] - date_list[0]
-        if date_range < timedelta(2):
-          date_formatter = DateFormatter('%Y-%m-%dT%H')
-          date_locator = HourLocator(
-            interval=int((date_range / 4).total_seconds() / 3600))
-        elif date_range < timedelta(6):
-          date_formatter = DateFormatter('%Y-%m-%d')
-          date_locator = DayLocator()
-        else:
-          date_locator = AutoDateLocator()
+        date_locator = AutoDateLocator(minticks=3, maxticks=5)
         date_formatter = AutoDateFormatter(date_locator)
+        date_formatter.scaled = {
+          365.: '%Y',
+          30.: '%Y/%m',
+          1.: '%Y/%m/%d',
+          1. / 24: '%Y/%m/%d\n%H:%M',
+        }
         apdex_plot = pyplot.subplot(2, 1, 1)
         apdex_plot.xaxis.set_major_locator(date_locator)
         apdex_plot.xaxis.set_major_formatter(date_formatter)