dataviz: add stacked bar percent chart type (#52845)

combo/apps/dataviz/migrations/0011_auto_20200813_1100.py

@@ -45,6 +45,7 @@ class Migration(migrations.Migration):
                     ('bar', 'Bar'),
                     ('horizontal-bar', 'Horizontal Bar'),
                     ('stacked-bar', 'Stacked Bar'),
+                    ('stacked-bar-percent', 'Stacked Bar (%)'),
                     ('line', 'Line'),
                     ('pie', 'Pie'),
                     ('dot', 'Dot'),

combo/apps/dataviz/models.py

@@ -190,6 +190,7 @@ class ChartNgCell(CellBase):
             ('bar', _('Bar')),
             ('horizontal-bar', _('Horizontal Bar')),
             ('stacked-bar', _('Stacked Bar')),
+            ('stacked-bar-percent', _('Stacked Bar (%)')),
             ('line', _('Line')),
             ('pie', _('Pie')),
             ('dot', _('Dot')),
@@ -306,6 +307,7 @@ class ChartNgCell(CellBase):
             'bar': pygal.Bar,
             'horizontal-bar': pygal.HorizontalBar,
             'stacked-bar': pygal.StackedBar,
+            'stacked-bar-percent': pygal.StackedBar,
             'line': pygal.Line,
             'pie': pygal.Pie,
             'dot': pygal.Dot,
@@ -337,6 +339,9 @@ class ChartNgCell(CellBase):
                         if data
                     ]
 
+            if self.chart_type == 'stacked-bar-percent':
+                self.make_percent([serie['data'] for serie in data['series']])
+
             for serie in data['series']:
                 chart.add(serie['label'], serie['data'])
 
@@ -485,12 +490,16 @@ class ChartNgCell(CellBase):
 
     def add_data_to_chart(self, chart, data, y_labels):
         if self.chart_type != 'pie':
+            series_data = []
             for i, serie_label in enumerate(y_labels):
                 if chart.axis_count < 2:
                     values = data
                 else:
                     values = [data[i][j] for j in range(len(chart.x_labels))]
+                series_data.append(values)
                 chart.add(serie_label, values)
+            if self.chart_type == 'stacked-bar-percent':
+                self.make_percent(series_data)
         else:
             # pie, create a serie by data, to get different colours
             values = data
@@ -529,3 +538,14 @@ class ChartNgCell(CellBase):
         elif measure == 'percent':
             percent_formatter = lambda x: '{:.1f}%'.format(x)
             return percent_formatter
+
+    def make_percent(self, series_data):
+        for i, values in enumerate(zip(*series_data)):
+            sum_values = sum([v for v in values if v is not None])
+            if sum_values == 0:
+                continue
+
+            factor = 100 / sum_values
+            for values in series_data:
+                if values[i] is not None:
+                    values[i] = round(values[i] * factor, 1)

tests/test_dataviz.py

@@ -441,6 +441,18 @@ def test_chartng_cell(app, statistics):
         ([122, 114, 2, 33], {'title': u'bar'}),
     ]
 
+    # stacked bar with percent
+    cell.chart_type = 'stacked-bar-percent'
+    cell.save()
+
+    chart = cell.get_chart()
+    assert chart.x_labels == ['web', 'mail', 'phone', 'email']
+    assert chart.raw_series == [
+        ([64.5, 54, 0, 61.6], {'title': u'foo'}),
+        ([35.5, 46, 100, 38.4], {'title': u'bar'}),
+    ]
+    assert all(x + y == 100 for x, y in zip(chart.raw_series[0][0], chart.raw_series[1][0]))
+
     # single data point
     cell.chart_type = 'bar'
     cell.statistic = Statistic.objects.get(slug='fourth')
@@ -533,6 +545,18 @@ def test_chartng_cell_new_api(app, new_api_statistics):
     assert chart.x_labels == ['2020-10', '2020-11', '2020-12']
     assert chart.raw_series == [([None, 16, 2], {'title': 'Serie 1'}), ([2, 1, None], {'title': 'Serie 2'})]
 
+    # stacked bar with percent
+    cell.chart_type = 'stacked-bar-percent'
+    cell.save()
+
+    chart = cell.get_chart()
+    assert chart.x_labels == ['2020-10', '2020-11', '2020-12']
+    assert chart.raw_series == [
+        ([None, 94.1, 100], {'title': 'Serie 1'}),
+        ([100, 5.9, None], {'title': 'Serie 2'}),
+    ]
+    assert all(x + y == 100 for x, y in zip(chart.raw_series[0][0], chart.raw_series[1][0]) if x and y)
+
     cell.statistic = Statistic.objects.get(slug='no-data')
     cell.save()