Support colorized shapes.

docs/index.rst

@@ -40,6 +40,19 @@ Show me code
 
 .. figure:: example.svg
 
+.. code-block:: python
+
+    dot_data = [(random.randint(0, 250), random.randint(0, 250)) for i in range(100)]
+
+    def colorizer(x, y, i):
+        return 'rgb(%i, %i, %i)' % (x, y, 150)
+
+    chart = leather.Chart('Something a little fancier')
+    chart.add_dots(dot_data, color=colorizer)
+    chart.to_svg('docs/example2.svg')
+
+.. figure:: example2.svg
+
 Join us
 =======
 

example.py

@@ -1,7 +1,10 @@
 #!/usr/bin env python
 
+import random
+
 import leather
 
+# Example 1
 
 data = [
     (0, 3),
@@ -14,3 +17,14 @@
 chart.add_lines(data)
 chart.add_dots(data)
 chart.to_svg('docs/example.svg')
+
+# Example 2
+
+dot_data = [(random.randint(0, 250), random.randint(0, 250)) for i in range(100)]
+
+def colorizer(x, y, i):
+    return 'rgb(%i, %i, %i)' % (x, y, 150)
+
+chart = leather.Chart('Well that was easy')
+chart.add_dots(dot_data, color=colorizer)
+chart.to_svg('docs/example2.svg')

leather/shapes/bars.py

@@ -12,10 +12,12 @@ class Bars(Shape):
     Render a series of data as bars.
 
     :param color:
-        The color to fill the bars.
+        The color to fill the bars. You may also specify a function, which will
+        be called with the arguments :code:`(x, y, index)` and should return a
+        color.
     """
     def __init__(self, color):
-        self.color = color
+        self._color = color
 
     def to_svg(self, width, height, x_scale, y_scale, series):
         """
@@ -24,19 +26,24 @@ def to_svg(self, width, height, x_scale, y_scale, series):
         group = ET.Element('g')
         group.set('class', 'series bars')
 
-        for x, y in series.data:
+        for i, (x, y) in enumerate(series.data):
             if x is None or y is None:
                 continue
 
             proj_x = x_scale.project(x, 0, width)
             y1, y2 = y_scale.project_interval(y, height, 0)
 
+            if callable(self._color):
+                color = self._color(x, y, i)
+            else:
+                color = self._color
+
             group.append(ET.Element('rect',
                 x=six.text_type(0),
                 y=six.text_type(y2),
                 width=six.text_type(proj_x),
                 height=six.text_type(y1 - y2),
-                fill=self.color
+                fill=color
             ))
 
         return group

leather/shapes/columns.py

@@ -12,10 +12,12 @@ class Columns(Shape):
     Render a series of data as columns.
 
     :param color:
-        The color to fill the columns.
+        The color to fill the columns. You may also specify a function, which
+        will be called with the arguments :code:`(x, y, index)` and should
+        return a color.
     """
     def __init__(self, color):
-        self.color = color
+        self._color = color
 
     def to_svg(self, width, height, x_scale, y_scale, series):
         """
@@ -24,19 +26,24 @@ def to_svg(self, width, height, x_scale, y_scale, series):
         group = ET.Element('g')
         group.set('class', 'series columns')
 
-        for x, y in series.data:
+        for i, (x, y) in enumerate(series.data):
             if x is None or y is None:
                 continue
 
             x1, x2 = x_scale.project_interval(x, 0, width)
             proj_y = y_scale.project(y, height, 0)
 
+            if callable(self._color):
+                color = self._color(x, y, i)
+            else:
+                color = self._color
+
             group.append(ET.Element('rect',
                 x=six.text_type(x1),
                 y=six.text_type(proj_y),
                 width=six.text_type(x2 - x1),
                 height=six.text_type(height - proj_y),
-                fill=self.color
+                fill=color
             ))
 
         return group

leather/shapes/dots.py

@@ -12,15 +12,17 @@ class Dots(Shape):
     """
     Render a series of data as dots.
 
-    :param color:
-        The color to fill the dots.
+    :param fill_color:
+        The color to fill the dots. You may also specify a function, which will
+        be called with the arguments :code:`(x, y, index)` and should return a
+        color.
     :param radius:
         The radius of the rendered dots. Defaults to
         :data:`.theme.default_dot_radius`.
     """
-    def __init__(self, color, radius=None):
-        self.color = color
-        self.radius = radius or theme.default_dot_radius
+    def __init__(self, fill_color, radius=None):
+        self._fill_color = fill_color
+        self._radius = radius or theme.default_dot_radius
 
     def to_svg(self, width, height, x_scale, y_scale, series):
         """
@@ -29,18 +31,23 @@ def to_svg(self, width, height, x_scale, y_scale, series):
         group = ET.Element('g')
         group.set('class', 'series dots')
 
-        for x, y in series.data:
+        for i, (x, y) in enumerate(series.data):
             if x is None or y is None:
                 continue
 
             proj_x = x_scale.project(x, 0, width)
             proj_y = y_scale.project(y, height, 0)
 
+            if callable(self._fill_color):
+                fill_color = self._fill_color(x, y, i)
+            else:
+                fill_color = self._fill_color
+
             group.append(ET.Element('circle',
                 cx=six.text_type(proj_x),
                 cy=six.text_type(proj_y),
-                r=six.text_type(self.radius),
-                fill=self.color
+                r=six.text_type(self._radius),
+                fill=fill_color
             ))
 
         return group

leather/shapes/lines.py

@@ -13,7 +13,7 @@ class Lines(Shape):
     Render a series of data as a lines.
 
     :param color:
-        The color to use for the line stroke.
+        The color to stroke the lines.
     :param width:
         The width of the lines. Defaults to :data:`.theme.default_line_width`.
     """

test.py

@@ -1,51 +1,54 @@
 #!/usr/bin/env python
 
-import leather
+import random
 
-dot_data = [
-    (0, 3),
-    (4, 5),
-    (7, 9),
-    (8, 4)
-]
+import leather
 
-line_data = [
-    (0, 4),
-    (1, 3),
-    (2, 5),
-    (5, 6),
-    (9, 10)
-]
+dot_data = [(random.randint(0, 250), random.randint(0, 250)) for i in range(100)]
 
-leather.theme.default_chart_width = 100
+def colorizer(x, y, i):
+    return 'rgb(%i, %i, %i)' % (x, y, 150)
 
-chart = leather.Chart()
-# chart.set_x_scale(leather.Linear(0, 20))
-chart.add_dots(dot_data)
-chart.add_lines(line_data)
+chart = leather.Chart('Well that was easy')
+chart.add_dots(dot_data, color=colorizer)
 chart.to_svg('test.svg')
 
-leather.theme.default_chart_width = 1000
-
-chart.to_svg('test2.svg')
-
 # dot_data = [
-#     ('foo', 3),
-#     ('bing', 5),
-#     ('baz', 9),
-#     ('blurg', 4)
+#     (0, 3),
+#     (4, 5),
+#     (7, 9),
+#     (8, 4)
 # ]
 #
 # line_data = [
-#     ('foo', 7),
-#     ('bing', 2),
-#     ('baz', 3),
-#     ('blurg', 4)
+#     (0, 4),
+#     (1, 3),
+#     (2, 5),
+#     (5, 6),
+#     (9, 10)
 # ]
 #
 # chart = leather.Chart()
-# chart.add_column(line_data)
-# chart.add_dot(dot_data)
+# # chart.set_x_scale(leather.Linear(0, 20))
+# chart.add_dots(dot_data)
+# chart.add_lines(line_data)
+# chart.to_svg('test.svg')
+
+# bar_data = [
+#     (3, 'foo'),
+#     (5, 'bing blaarg murg'),
+#     (9, 'baz'),
+#     (4, 'blurg')
+# ]
+#
+# def colorizer(x, y, i):
+#     if y == 'baz':
+#         return 'yellow'
+#     else:
+#         return 'blue'
+#
+# chart = leather.Chart('Bar charts are fun')
+# chart.add_dots(bar_data, color=colorizer)
 # chart.to_svg('test.svg')
 #
 # data = [[