Fix #148

CHANGELOG

@@ -3,6 +3,8 @@ V 2.0.0 UNRELEASED
 	Refactor maps
 	Add swiss cantons map (thanks sergedroz)
 	Add inverse_y_axis options to reverse graph (#24)
+	Fix DateTimeLine time data loss (#193)
+	Fix no data for graphs with only zeroes (#148)
 
 V 1.7.0
 	Remove DateY and replace it by real XY datetime, date, time and timedelta support. (#188)

pygal/graph/graph.py

@@ -22,6 +22,7 @@ Commmon graphing functions
 """
 
 from __future__ import division
+from pygal._compat import is_list_like
 from pygal.interpolate import INTERPOLATIONS
 from pygal.graph.base import BaseGraph
 from pygal.view import View, LogView, XYLogView, ReverseView
@@ -710,13 +711,14 @@ class Graph(BaseGraph):
         self._post_compute()
         self._compute_margin()
         self._decorate()
-        if self.series and self._has_data():
+        if self.series and self._has_data() and self._values:
             self._plot()
         else:
             self.svg.draw_no_data()
 
     def _has_data(self):
         """Check if there is any data"""
-        return sum(
-            map(len, map(lambda s: s.safe_values, self.series))) != 0 and (
-            sum(map(abs, self._values)) != 0)
+        return any([
+            len([v for v in (s[1] if is_list_like(s) else [s]) if v is not None])
+            for s in self.raw_series
+        ])