Fix stacked lines

pygal/graph/base.py

@@ -177,6 +177,10 @@ class BaseGraph(object):
                 diff = self._len - len(serie.values)
                 serie.metadata += diff * [self.__value__(0)]
 
+            for metadata in serie.metadata:
+                if metadata.value == None:
+                    metadata.value = 0
+
     def _render(self):
         """Make the graph internally"""
         self.reinit()

pygal/graph/line.py

@@ -99,11 +99,12 @@ class Line(Graph):
         ] if self._len != 1 else [.5]  # Center if only one value
 
         for serie in self.series:
-            serie.points = [
-                (x_pos[i], v)
-                for i, v in enumerate(serie.values)]
-            if self.interpolate:
-                serie.interpolated = self._interpolate(serie.values, x_pos)
+            if not hasattr(serie, 'points'):
+                serie.points = [
+                    (x_pos[i], v)
+                    for i, v in enumerate(serie.values)]
+                if self.interpolate:
+                    serie.interpolated = self._interpolate(serie.values, x_pos)
 
         if self.include_x_axis:
             self._box.ymin = min(self._min, 0)

pygal/graph/stackedline.py

@@ -46,10 +46,7 @@ class StackedLine(Line):
         ] if self._len != 1 else [.5]  # Center if only one value
         accumulation = [0] * self._len
         for serie in self.series:
-            accumulation = map(sum, izip_longest(
-                accumulation, [val
-                               if val != None else 0
-                               for val in serie.values], fillvalue=0))
+            accumulation = map(sum, zip(accumulation, serie.values))
             serie.points = [
                 (x_pos[i], v)
                 for i, v in enumerate(accumulation)]

pygal/style.py

@@ -34,10 +34,10 @@ class Style(object):
         opacity_hover='.9',
         transition='250ms',
         colors=(
-                '#ff5995', '#b6e354', '#feed6c', '#8cedff', '#9e6ffe',
-                '#899ca1', '#f8f8f2', '#808384', '#bf4646', '#516083',
-                '#f92672', '#82b414', '#fd971f', '#56c2d6', '#8c54fe',
-                '#465457')):
+            '#ff5995', '#b6e354', '#feed6c', '#8cedff', '#9e6ffe',
+            '#899ca1', '#f8f8f2', '#bf4646', '#516083', '#f92672',
+            '#82b414', '#fd971f', '#56c2d6', '#808384', '#8c54fe',
+            '#465457')):
         self.background = background
         self.plot_background = plot_background
         self.foreground = foreground