Added new option to config 'half_pie' to allow only creating half of a pie chart, for Kozea#123 [Fixes: #123]

CHANGELOG

@@ -1,5 +1,6 @@
 V 1.5.0 UNRELEASED
 	Add per serie configuration
+	Add half pie (thanks philt2001)
 
 V 1.4.6
 	Add support for \n separated multiline titles (thanks sirlark)

demo/moulinrouge/tests.py

@@ -479,6 +479,14 @@ def get_test_routes(app):
 
         return pie.render_response()
 
+    @app.route('/test/half_pie')
+    def test_half_pie():
+        pie = Pie(half_pie=True)
+        for i in range(10):
+            pie.add(str(i), i, inner_radius=.1)
+
+        return pie.render_response()
+
     @app.route('/test/legend_at_bottom/<chart>')
     def test_legend_at_bottom_for(chart):
         graph = CHARTS_BY_NAME[chart]()

pygal/config.py

@@ -234,7 +234,12 @@ class Config(CommonConfig):
 
     tooltip_border_radius = Key(0, int, "Look", "Tooltip border radius")
 
-    # Label #
+    inner_radius = Key(
+        0, float, "Look", "Piechart inner radius (donut), must be <.9")
+
+    half_pie = Key(
+        False, bool, "Look", "Create a half-pie chart")
+
     x_labels = Key(
         None, list, "Label",
         "X labels, must have same len than data.",

pygal/graph/pie.py

@@ -41,12 +41,20 @@ class Pie(Graph):
         serie_angle = 0
         total_perc = 0
         original_start_angle = start_angle
-        center = ((self.width - self.margin.x) / 2.,
-                  (self.height - self.margin.y) / 2.)
+        if self.half_pie:
+            center = ((self.width - self.margin.x) / 2.,
+                      (self.height - self.margin.y) / 1.25)
+        else:
+            center = ((self.width - self.margin.x) / 2.,
+                      (self.height - self.margin.y) / 2.)
+
         radius = min(center)
         for i, val in enumerate(serie.values):
             perc = val / total
-            angle = 2 * pi * perc
+            if self.half_pie:
+                angle = 2 * pi * perc / 2
+            else:
+                angle = 2 * pi * perc
             serie_angle += angle
             val = '{0:.2%}'.format(perc)
             metadata = serie.metadata.get(i)
@@ -77,7 +85,13 @@ class Pie(Graph):
 
     def _plot(self):
         total = sum(map(sum, map(lambda x: x.values, self.series)))
-        current_angle = 0
+        if total == 0:
+            return
+        if self.half_pie:
+            current_angle = 3*pi/2
+        else:
+            current_angle = 0
+
         for index, serie in enumerate(self.series):
             angle = self.slice(
                 self._serie(index), current_angle, serie, total)

pygal/test/test_donut.py

@@ -16,15 +16,10 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with pygal. If not, see <http://www.gnu.org/licenses/>.
-import os
-import uuid
 from pygal import Pie
 
 
 def test_donut():
-    file_name = '/tmp/test_graph-%s.svg' % uuid.uuid4()
-    if os.path.exists(file_name):
-        os.remove(file_name)
     chart = Pie(inner_radius=.3, pretty_print=True)
     chart.title = 'Browser usage in February 2012 (in %)'
     chart.add('IE', 19.5)
@@ -32,17 +27,12 @@ def test_donut():
     chart.add('Chrome', 36.3)
     chart.add('Safari', 4.5)
     chart.add('Opera', 2.3)
-    chart.render_to_file(file_name)
-    with open(file_name) as f:
-        assert 'pygal' in f.read()
-    os.remove(file_name)
+    assert chart.render()
 
 
 def test_multiseries_donut():
-    #this just demos that the multiseries pie does not respect the inner_radius
-    file_name = '/tmp/test_graph-%s.svg' % uuid.uuid4()
-    if os.path.exists(file_name):
-        os.remove(file_name)
+    # this just demos that the multiseries pie does not respect
+    # the inner_radius
     chart = Pie(inner_radius=.3, pretty_print=True)
     chart.title = 'Browser usage by version in February 2012 (in %)'
     chart.add('IE', [5.7, 10.2, 2.6, 1])
@@ -50,7 +40,21 @@ def test_multiseries_donut():
     chart.add('Chrome', [.3, .9, 17.1, 15.3, .6, .5, 1.6])
     chart.add('Safari', [4.4, .1])
     chart.add('Opera', [.1, 1.6, .1, .5])
-    chart.render_to_file(file_name)
-    with open(file_name) as f:
-        assert 'pygal' in f.read()
-    os.remove(file_name)
+    assert chart.render()
+
+
+def test_half_pie():
+    pie = Pie()
+    pie.add('IE', 19.5)
+    pie.add('Firefox', 36.6)
+    pie.add('Chrome', 36.3)
+    pie.add('Safari', 4.5)
+    pie.add('Opera', 2.3)
+
+    half = Pie(half_pie=True)
+    half.add('IE', 19.5)
+    half.add('Firefox', 36.6)
+    half.add('Chrome', 36.3)
+    half.add('Safari', 4.5)
+    half.add('Opera', 2.3)
+    assert pie.render() != half.render()