Add defs config key.

demo/moulinrouge/tests.py

@@ -913,4 +913,42 @@ def test_legend_link_for(chart):
 
         return chart.render_response()
 
-    return list(sorted(filter(lambda x: x.startswith('test'), locals())))
+    @app.route('/test/gradient/<chart>')
+    def test_gradient_for(chart):
+
+        config = Config()
+        config.style = styles['dark']
+        config.defs.append('''
+          <linearGradient id="gradient-0" x1="0" x2="0" y1="0" y2="1">
+            <stop offset="0%" stop-color="#ff5995" />
+            <stop offset="100%" stop-color="#feed6c" />
+          </linearGradient>
+        ''')
+        config.defs.append('''
+          <linearGradient id="gradient-1" x1="0" x2="0" y1="0" y2="1">
+            <stop offset="0%" stop-color="#b6e354" />
+            <stop offset="100%" stop-color="#8cedff" />
+          </linearGradient>
+        ''')
+        config.css.append('''inline:
+          .color-0 {
+            fill: url(#gradient-0) !important;
+            stroke: url(#gradient-0) !important;
+          }''')
+        config.css.append('''inline:
+          .color-1 {
+            fill: url(#gradient-1) !important;
+            stroke: url(#gradient-1) !important;
+          }''')
+        chart = CHARTS_BY_NAME[chart](config)
+        chart.add('1', [1, 3, 12, 3, 4, None, 9])
+        chart.add('2', [7, -4, 10, None, 8, 3, 1])
+        chart.x_labels = ('a', 'b', 'c', 'd', 'e', 'f', 'g')
+        chart.legend_at_bottom = True
+        chart.interpolate = 'cubic'
+        return chart.render_response()
+
+    return list(sorted(filter(
+        lambda x: x.startswith('test') and not x.endswith('_for'), locals()))
+    ) + list(sorted(filter(
+        lambda x: x.startswith('test') and x.endswith('_for'), locals())))

docs/changelog.rst

@@ -11,6 +11,7 @@ Changelog
 * Fix labels rotation > 180 (#257)
 * Fix secondary axis
 * Don't forget secondary series in table rendering (#260)
+* Add `defs` config option to allow adding gradients and patterns.
 
 2.0.8
 =====

docs/documentation/configuration/rendering.rst

@@ -132,6 +132,46 @@ Css can also specified inline by prepending `inline:` to the css:
    css = ['inline:.rect { fill: blue; }']
 
 
+defs
+----
+
+You can add defs like linearGradient, radialGradient, pattern to the defs config:
+
+
+.. pygal-code::
+
+    config = pygal.Config()
+    config.style = pygal.style.DarkStyle
+    config.defs.append('''
+      <linearGradient id="gradient-0" x1="0" x2="0" y1="0" y2="1">
+        <stop offset="0%" stop-color="#ff5995" />
+        <stop offset="100%" stop-color="#feed6c" />
+      </linearGradient>
+    ''')
+    config.defs.append('''
+      <linearGradient id="gradient-1" x1="0" x2="0" y1="0" y2="1">
+        <stop offset="0%" stop-color="#b6e354" />
+        <stop offset="100%" stop-color="#8cedff" />
+      </linearGradient>
+    ''')
+    config.css.append('''inline:
+      .color-0 {
+        fill: url(#gradient-0) !important;
+        stroke: url(#gradient-0) !important;
+      }''')
+    config.css.append('''inline:
+      .color-1 {
+        fill: url(#gradient-1) !important;
+        stroke: url(#gradient-1) !important;
+      }''')
+    chart = pygal.Line(config)
+    chart.add('1', [1, 3, 12, 3, 4, None, 9])
+    chart.add('2', [7, -4, 10, None, 8, 3, 1])
+    chart.x_labels = ('a', 'b', 'c', 'd', 'e', 'f', 'g')
+    chart.legend_at_bottom = True
+    chart.interpolate = 'cubic'
+
+
 js
 --
 

pygal/colors.py

@@ -34,6 +34,9 @@ def normalize_float(f):
 
 def rgb_to_hsl(r, g, b):
     """Convert a color in r, g, b to a color in h, s, l"""
+    r = r or 0
+    g = g or 0
+    b = b or 0
     r /= 255
     g /= 255
     b /= 255

pygal/config.py

@@ -232,6 +232,12 @@ class Config(CommonConfig):
         "It can be any uri from file:///tmp/style.css to //domain/style.css",
         str)
 
+    defs = Key(
+        [],
+        list, "Misc", "Extraneous defs to be inserted in svg",
+        "Useful for adding gradients / patterns…",
+        str)
+
     # Look #
     title = Key(
         None, str, "Look",

pygal/svg.py

@@ -80,6 +80,9 @@ def __init__(self, graph):
         self.title = self.node(tag='title')
         self.title.text = graph.title or 'Pygal'
 
+        for def_ in self.graph.defs:
+            self.defs.append(etree.fromstring(def_))
+
     def add_styles(self):
         """Add the css to the svg"""
         colors = self.graph.style.get_colors(self.id, self.graph._order)