Fix stacked

demo/moulinrouge/tests.py

@@ -104,6 +104,8 @@ def get_test_routes(app):
         graph = CHARTS_BY_NAME[chart]()
         graph.add('1', [1, 3, 12, 3, 4, None, 9])
         graph.add('2', [7, -4, 10, None, 8, 3, 1])
+        graph.add('3', [7, -14, -10, None, 8, 3, 1])
+        graph.add('4', [7, 4, -10, None, 8, 3, 1])
         graph.x_labels = ('a', 'b', 'c', 'd', 'e', 'f', 'g')
         return graph.render_response()
 

pygal/graph/bar.py

@@ -36,17 +36,20 @@ class Bar(Graph):
         self._x_ranges = None
         super(Bar, self).__init__(*args, **kwargs)
 
-    def _bar(self, parent, x, y, index):
+    def _bar(self, parent, x, y, index, i, zero, shift=True):
         width = (self.view.x(1) - self.view.x(0)) / self._len
+        x, y = self.view((x, y))
         series_margin = width * self._series_margin
         x += series_margin
         width -= 2 * series_margin
+        if shift:
             width /= self._order
             x += index * width
             serie_margin = width * self._serie_margin
             x += serie_margin
             width -= 2 * serie_margin
-        height = self.view.y(self.zero) - y
+        height = self.view.y(zero) - y
+        print height
         r = self.rounded_bars * 1 if self.rounded_bars else 0
         self.svg.transposable_node(
             parent, 'rect',
@@ -58,8 +61,7 @@ class Bar(Graph):
     def bar(self, serie_node, serie, index):
         """Draw a bar graph for a serie"""
         bars = self.svg.node(serie_node['plot'], class_="bars")
-        view_values = map(self.view, serie.points)
-        for i, (x, y) in enumerate(view_values):
+        for i, (x, y) in enumerate(serie.points):
             if None in (x, y):
                 continue
             metadata = serie.metadata.get(i)
@@ -68,9 +70,10 @@ class Bar(Graph):
                 self.svg,
                 self.svg.node(bars, class_='bar'),
                 metadata)
-            val = self._get_value(serie.points, i)
+            val = self._format(serie.values[i])
 
-            x_center, y_center = self._bar(bar, x, y, index)
+            x_center, y_center = self._bar(
+                bar, x, y, index, i, self.zero)
             self._tooltip_data(
                 bar, val, x_center, y_center, classes="centered")
             self._static_value(serie_node, val, x_center, y_center)

pygal/graph/base.py

@@ -49,9 +49,9 @@ class BaseGraph(object):
         self.view = None
         if self.logarithmic and self.zero == 0:
             # Explicit min to avoid interpolation dependency
-            self.zero = min(
-                val for serie in self.series for val in serie.values)
-
+            self.zero = min(filter(
+                lambda x: x > 0,
+                [val for serie in self.series for val in serie.safe_values]))
         if self.series and self._has_data():
             self._draw()
         else:

pygal/graph/stackedbar.py

@@ -24,23 +24,29 @@ Stacked Bar chart
 from __future__ import division
 from pygal.graph.bar import Bar
 from pygal.util import compute_scale
+from pygal.adapters import none_to_zero
 
 
 class StackedBar(Bar):
     """Stacked Bar graph"""
 
+    _adapters = [none_to_zero]
+
     def _compute(self):
         transposed = zip(*[serie.values for serie in self.series])
         positive_vals = [sum([
-            val if val is not None and val > self.zero else self.zero
-            for val in vals]) - self.zero
+            val for val in vals
+            if val is not None and val >= self.zero])
             for vals in transposed]
         negative_vals = [sum([
-            val - self.zero
-            if val is not None and val < self.zero else self.zero
-            for val in vals]) + self.zero
+            val
+            for val in vals
+            if val is not None and val < self.zero])
             for vals in transposed]
 
+        positive_vals = positive_vals or [self.zero]
+        negative_vals = negative_vals or [self.zero]
+
         self._box.ymin, self._box.ymax = (
             min(min(negative_vals), self.zero),
             max(max(positive_vals), self.zero))
@@ -48,6 +54,8 @@ class StackedBar(Bar):
         x_pos = [
             x / self._len for x in range(self._len + 1)
         ] if self._len > 1 else [0, 1]  # Center if only one value
+
+        self._points(x_pos)
         y_pos = compute_scale(
             self._box.ymin, self._box.ymax, self.logarithmic, self.order_min
         ) if not self.y_labels else map(float, self.y_labels)
@@ -57,12 +65,16 @@ class StackedBar(Bar):
             sum(x_range) / 2 for x_range in self._x_ranges])
         self._y_labels = zip(map(self._format, y_pos), y_pos)
 
-    def _points(self, x_pos):
-        accumulation = [0] * self._len
-        for serie in self.series:
-            accumulation = map(sum, zip(accumulation, serie.values))
-            serie.points = [
-                (x_pos[i], v)
-                for i, v in enumerate(accumulation)]
-            if self.interpolate:
-                serie.interpolated = self._interpolate(accumulation, x_pos)
+        self.negative_cumulation = [0] * self._len
+        self.positive_cumulation = [0] * self._len
+
+    def _bar(self, parent, x, val, index, i, zero):
+        cumulation = (self.negative_cumulation if val < self.zero else
+                      self.positive_cumulation)
+        zero = cumulation[i]
+        cumulation[i] = zero + val
+        if zero == 0:
+            zero = self.zero
+            val -= self.zero
+        return super(StackedBar, self)._bar(
+            parent, x, zero + val, index, i, zero, False)