Fix zero line rendering. Closes #31.

CHANGELOG.rst

@@ -1,6 +1,7 @@
 0.3.0
 -----
 
+* Zero lines now render above other tick marks. (#31)
 * Fixed rendering of :class:`.Bar` and :class:`.Column` shapes for negative values.
 * Refactored the :class:`.Lattice` API.
 

leather/axis.py

@@ -101,11 +101,17 @@ def to_svg(self, width, height, scale, orient):
         tick_values = scale.ticks(self._ticks)
         tick_count = len(tick_values)
 
+        zero_tick_group = None
+
         for i, value in enumerate(tick_values):
             # Tick group
             tick_group = ET.Element('g')
             tick_group.set('class', 'tick')
-            group.append(tick_group)
+
+            if value == 0:
+                zero_tick_group = tick_group
+            else:
+                group.append(tick_group)
 
             # Tick line
             projected_value = scale.project(value, range_min, range_max)
@@ -160,6 +166,9 @@ def to_svg(self, width, height, scale, orient):
 
             tick_group.append(label)
 
+        if zero_tick_group:
+            group.append(zero_tick_group)
+
         return group
 
 

test.py

@@ -1,11 +1,11 @@
 import leather
 
 data = [
-    (-3, 'foo', -3),
-    (5, 'bar', 5),
-    (-9, 'baz', -9)
+    (-1, -1),
+    (0, 0),
+    (1, 1)
 ]
 
-chart = leather.Chart('Negative columns')
-chart.add_bars(data)
+chart = leather.Chart()
+chart.add_lines(data)
 chart.to_svg('test.svg')

tests/test_axis.py

@@ -30,4 +30,4 @@ def test_formatter(value, i, count):
 
         svg = self.render_chart(chart)
 
-        self.assertTickLabels(svg, 'bottom', ['0+', '25+', '50+', '75+', '100+'])
+        self.assertTickLabels(svg, 'bottom', ['25+', '50+', '75+', '100+', '0+'])

tests/test_chart.py

@@ -57,8 +57,8 @@ def test_set_scales(self):
 
         svg = self.render_chart(chart)
 
-        self.assertTickLabels(svg, 'left', ['0.0', '5.0', '10.0', '15.0', '20.0'])
-        self.assertTickLabels(svg, 'bottom', ['0.0', '5.0', '10.0', '15.0', '20.0'])
+        self.assertTickLabels(svg, 'left', ['5.0', '10.0', '15.0', '20.0', '0.0'])
+        self.assertTickLabels(svg, 'bottom', ['5.0', '10.0', '15.0', '20.0', '0.0'])
 
     def test_add_scales(self):
         chart = leather.Chart()
@@ -68,8 +68,8 @@ def test_add_scales(self):
 
         svg = self.render_chart(chart)
 
-        self.assertTickLabels(svg, 'left', ['0.0', '5.0', '10.0', '15.0', '20.0'])
-        self.assertTickLabels(svg, 'bottom', ['0.0', '5.0', '10.0', '15.0', '20.0'])
+        self.assertTickLabels(svg, 'left', ['5.0', '10.0', '15.0', '20.0', '0.0'])
+        self.assertTickLabels(svg, 'bottom', ['5.0', '10.0', '15.0', '20.0', '0.0'])
 
     def test_set_axes(self):
         chart = leather.Chart()
@@ -80,7 +80,7 @@ def test_set_axes(self):
         svg = self.render_chart(chart)
 
         self.assertTickLabels(svg, 'left', ['3.0', '6.0', '9.0'])
-        self.assertTickLabels(svg, 'bottom', ['0.0', '4.0', '8.0'])
+        self.assertTickLabels(svg, 'bottom', ['4.0', '8.0', '0.0'])
 
     def test_add_axes(self):
         chart = leather.Chart()
@@ -91,4 +91,4 @@ def test_add_axes(self):
         svg = self.render_chart(chart)
 
         self.assertTickLabels(svg, 'left', ['3.0', '6.0', '9.0'])
-        self.assertTickLabels(svg, 'bottom', ['0.0', '4.0', '8.0'])
+        self.assertTickLabels(svg, 'bottom', ['4.0', '8.0', '0.0'])