From 80f39a19c4b7ad125dde15f75e85c0c2e49e9a0c Mon Sep 17 00:00:00 2001
From: Florian Mounier <florian.mounier@kozea.fr>
Date: Tue, 14 Feb 2012 17:59:27 +0100
Subject: [PATCH] Big refactor and add radar graph

---
 out.py                    |   4 +-
 pygal/config.py           |   2 +
 pygal/css/graph.css       |  10 +-
 pygal/graph/bar.py        |  65 +++++++++-
 pygal/graph/base.py       |   8 --
 pygal/graph/graph.py      | 128 +++++++++++++++++++
 pygal/graph/horizontal.py |   3 +-
 pygal/graph/line.py       |  22 +++-
 pygal/graph/pie.py        |  35 +++++-
 pygal/graph/radar.py      |  76 ++++++++++--
 pygal/graph/stackedbar.py |   8 +-
 pygal/graph/xy.py         |  11 +-
 pygal/style.py            |   3 +
 pygal/svg.py              | 251 +++-----------------------------------
 pygal/util.py             |   4 +
 pygal/view.py             |  10 ++
 16 files changed, 358 insertions(+), 282 deletions(-)
 create mode 100644 pygal/graph/graph.py

diff --git a/out.py b/out.py
index 3f177ed..ba63be4 100755
--- a/out.py
+++ b/out.py
@@ -82,10 +82,12 @@ with open('out-pie.svg', 'w') as f:
     f.write(pie.render())
 
 config = Config()
+config.fill = True
+config.style = NeonStyle
 config.x_labels = (
     'black', 'red', 'blue', 'yellow', 'orange', 'green', 'white')
 radar = Radar(config)
-radar.add('test', [9, 10, 3, 5, 7, 2, 5])
+radar.add('test', [1, 4, 1, 5, 7, 2, 5])
 radar.add('test2', [10, 2, 0, 5, 1, 9, 4])
 
 radar.title = "Radar test"
diff --git a/pygal/config.py b/pygal/config.py
index 3529709..6535668 100644
--- a/pygal/config.py
+++ b/pygal/config.py
@@ -41,6 +41,8 @@ class Config(object):
     rounded_bars = False
     # Always include x axis
     x_start_at_zero = False
+    # Fill areas
+    fill = False
 
     def __init__(self, **kwargs):
         """Can be instanciated with config kwargs"""
diff --git a/pygal/css/graph.css b/pygal/css/graph.css
index b926762..e5cc2c6 100644
--- a/pygal/css/graph.css
+++ b/pygal/css/graph.css
@@ -20,6 +20,10 @@ svg * {
   fill: {{ style.foreground }};
 }
 
+.line {
+  fill-opacity: 0;
+}
+
 .title {
   fill: {{ style.foreground_light }};
   font-size: {{ font_sizes.title }};
@@ -53,7 +57,7 @@ svg * {
   text-anchor: middle;
 }
 
-.axis.x text[transform] {
+.axis.x:not(.web) text[transform] {
   text-anchor: start;
 }
 
@@ -115,13 +119,13 @@ svg * {
 }
 
 .series .line {
-  fill: none;
   stroke-width: 1px;
+  fill-opacity: {{ fill_opacity }};
 }
 
 .series .line:hover {
-  fill: none;
   stroke-width: 2px;
+  fill-opacity: {{ fill_opacity_hover }};
 }
 
 
diff --git a/pygal/graph/bar.py b/pygal/graph/bar.py
index a5a887d..088eead 100644
--- a/pygal/graph/bar.py
+++ b/pygal/graph/bar.py
@@ -1,9 +1,66 @@
-from pygal.graph.base import BaseGraph
+from pygal.graph.graph import Graph
+from pygal.util import swap, ident
 
 
-class Bar(BaseGraph):
+class Bar(Graph):
     """Bar graph"""
 
+    def bar(self, serie_node, serie, values, stack_vals=None):
+        """Draw a bar graph for a serie"""
+        # value here is a list of tuple range of tuple coord
+
+        def view(rng):
+            """Project range"""
+            t, T = rng
+            fun = swap if self.horizontal else ident
+            return (self.view(fun(t)), self.view(fun(T)))
+
+        bars = self.svg.node(serie_node, class_="bars")
+        view_values = map(view, values)
+        for i, ((x, y), (X, Y)) in enumerate(view_values):
+            # x and y are left range coords and X, Y right ones
+            if self.horizontal:
+                x, y, X, Y = Y, X, y, x
+            width = X - x
+            padding = .1 * width
+            inner_width = width - 2 * padding
+            if self.horizontal:
+                height = self.view.x(0) - y
+            else:
+                height = self.view.y(0) - y
+            if stack_vals == None:
+                bar_width = inner_width / len(self.series)
+                bar_padding = .1 * bar_width
+                bar_inner_width = bar_width - 2 * bar_padding
+                offset = serie.index * bar_width + bar_padding
+                shift = 0
+            else:
+                offset = 0
+                bar_inner_width = inner_width
+                shift = stack_vals[i][int(height < 0)]
+                stack_vals[i][int(height < 0)] += height
+            x = x + padding + offset
+
+            if height < 0:
+                y = y + height
+                height = -height
+
+            y_txt = y + height / 2 + .3 * self.values_font_size
+            bar = self.svg.node(bars, class_='bar')
+            self.svg.transposable_node(bar, 'rect',
+                      x=x,
+                      y=y - shift,
+                      rx=self.rounded_bars * 1,
+                      ry=self.rounded_bars * 1,
+                      width=bar_inner_width,
+                      height=height,
+                      class_='rect')
+            self.svg.transposable_node(bar, 'text',
+                      x=x + bar_inner_width / 2,
+                      y=y_txt - shift,
+            ).text = str(values[i][1][1])
+        return stack_vals
+
     def _compute(self):
         vals = [val for serie in self.series for val in serie.values]
         self._box.ymin, self._box.ymax = min(min(vals), 0), max(max(vals), 0)
@@ -20,7 +77,7 @@ class Bar(BaseGraph):
 
     def _plot(self):
         for serie in self.series:
-            serie_node = self.svg.serie(serie.index)
-            self.svg.bar(serie_node, serie, [
+            serie_node = self._serie(serie.index)
+            self.bar(serie_node, serie, [
                 tuple((self._x_ranges[i][j], v) for j in range(2))
                 for i, v in enumerate(serie.values)])
diff --git a/pygal/graph/base.py b/pygal/graph/base.py
index b53f2fc..9bcf856 100644
--- a/pygal/graph/base.py
+++ b/pygal/graph/base.py
@@ -86,14 +86,6 @@ class BaseGraph(object):
     def _legends(self):
         return [serie.title for serie in self.series]
 
-    def _decorate(self):
-        self.svg.set_view()
-        self.svg.make_graph()
-        self.svg.x_axis()
-        self.svg.y_axis()
-        self.svg.legend()
-        self.svg.title()
-
     def _draw(self):
         self._compute()
         self._compute_margin()
diff --git a/pygal/graph/graph.py b/pygal/graph/graph.py
new file mode 100644
index 0000000..4a57bc2
--- /dev/null
+++ b/pygal/graph/graph.py
@@ -0,0 +1,128 @@
+from pygal.graph.base import BaseGraph
+from pygal.view import View
+
+
+class Graph(BaseGraph):
+    """Graph super class containing generic common functions"""
+
+    def _decorate(self):
+        self._set_view()
+        self._make_graph()
+        self._x_axis()
+        self._y_axis()
+        self._legend()
+        self._title()
+
+    def _set_view(self):
+        self.view = View(
+            self.width - self.margin.x,
+            self.height - self.margin.y,
+            self._box)
+
+    def _make_graph(self):
+        self.graph_node = self.svg.node(
+            class_='graph %s' % self.__class__.__name__)
+        self.svg.node(self.graph_node, 'rect',
+                  class_='background',
+                  x=0, y=0,
+                  width=self.width,
+                  height=self.height)
+        self.plot = self.svg.node(
+            self.graph_node, class_="plot",
+            transform="translate(%d, %d)" % (
+                self.margin.left, self.margin.top))
+        self.svg.node(self.plot, 'rect',
+                  class_='background',
+                  x=0, y=0,
+                  width=self.view.width,
+                  height=self.view.height)
+
+    def _x_axis(self):
+        if not self._x_labels:
+            return
+
+        axis = self.svg.node(self.plot, class_="axis x")
+
+        if 0 not in [label[1] for label in self._x_labels]:
+            self.svg.node(axis, 'path',
+                      d='M%f %f v%f' % (0, 0, self.view.height),
+                      class_='line')
+        for label, position in self._x_labels:
+            guides = self.svg.node(axis, class_='guides')
+            x = self.view.x(position)
+            y = self.view.height + 5
+            self.svg.node(guides, 'path',
+                      d='M%f %f v%f' % (x, 0, self.view.height),
+                    class_='%sline' % (
+                        'guide ' if position != 0 else ''))
+            text = self.svg.node(guides, 'text',
+                             x=x,
+                             y=y + .5 * self.label_font_size + 5
+            )
+            text.text = label
+            if self.x_label_rotation:
+                text.attrib['transform'] = "rotate(%d %f %f)" % (
+                    self.x_label_rotation, x, y)
+
+    def _y_axis(self):
+        if not self._y_labels:
+            return
+
+        axis = self.svg.node(self.plot, class_="axis y")
+
+        if 0 not in [label[1] for label in self._y_labels]:
+            self.svg.node(axis, 'path',
+                      d='M%f %f h%f' % (0, self.view.height, self.view.width),
+                      class_='line')
+        for label, position in self._y_labels:
+            guides = self.svg.node(axis, class_='guides')
+            x = -5
+            y = self.view.y(position)
+            self.svg.node(guides, 'path',
+                      d='M%f %f h%f' % (0, y, self.view.width),
+                      class_='%sline' % (
+                          'guide ' if position != 0 else ''))
+            text = self.svg.node(guides, 'text',
+                             x=x,
+                             y=y + .35 * self.label_font_size
+            )
+            text.text = label
+            if self.y_label_rotation:
+                text.attrib['transform'] = "rotate(%d %f %f)" % (
+                    self.y_label_rotation, x, y)
+
+    def _legend(self):
+        if not self.show_legend:
+            return
+        legends = self.svg.node(
+            self.graph_node, class_='legends',
+            transform='translate(%d, %d)' % (
+                self.margin.left + self.view.width + 10,
+                self.margin.top + 10))
+        for i, title in enumerate(self._legends):
+            legend = self.svg.node(legends, class_='legend')
+            self.svg.node(legend, 'rect',
+                      x=0,
+                      y=1.5 * i * self.legend_box_size,
+                      width=self.legend_box_size,
+                      height=self.legend_box_size,
+                      class_="color-%d" % i,
+                  ).text = title
+            # Serious magical numbers here
+            self.svg.node(legend, 'text',
+                      x=self.legend_box_size + 5,
+                      y=1.5 * i * self.legend_box_size
+                      + .5 * self.legend_box_size
+                      + .3 * self.legend_font_size
+            ).text = title
+
+    def _title(self):
+        if self.title:
+            self.svg.node(self.graph_node, 'text', class_='title',
+                      x=self.margin.left + self.view.width / 2,
+                      y=self.title_font_size + 10
+            ).text = self.title
+
+    def _serie(self, serie):
+        return self.svg.node(
+            self.plot, class_='series serie-%d color-%d' % (serie, serie))
diff --git a/pygal/graph/horizontal.py b/pygal/graph/horizontal.py
index 83a791c..bb4b5c0 100644
--- a/pygal/graph/horizontal.py
+++ b/pygal/graph/horizontal.py
@@ -1,8 +1,9 @@
+from pygal.graph.graph import Graph
 from pygal.graph.bar import Bar
 from pygal.graph.stackedbar import StackedBar
 
 
-class HorizontalGraph(object):
+class HorizontalGraph(Graph):
     """Horizontal graph"""
     def __init__(self, *args, **kwargs):
         kwargs['horizontal'] = True
diff --git a/pygal/graph/line.py b/pygal/graph/line.py
index 9d78f13..3f1d1d7 100644
--- a/pygal/graph/line.py
+++ b/pygal/graph/line.py
@@ -1,9 +1,23 @@
-from pygal.graph.base import BaseGraph
+from pygal.graph.graph import Graph
 
 
-class Line(BaseGraph):
+class Line(Graph):
     """Line graph"""
 
+    def _get_value(self, values, i):
+        return str(values[i][1])
+
+    def line(self, serie_node, values):
+        view_values = map(self.view, values)
+
+        dots = self.svg.node(serie_node, class_="dots")
+        for i, (x, y) in enumerate(view_values):
+            dot = self.svg.node(dots, class_='dot')
+            self.svg.node(dot, 'circle', cx=x, cy=y, r=2.5)
+            self.svg.node(dot, 'text', x=x, y=y
+            ).text = self._get_value(values, i)
+        self.svg.line(serie_node, view_values, class_='line', close=True)
+
     def _compute(self):
         vals = [val for serie in self.series for val in serie.values]
         self._box.ymin, self._box.ymax = min(vals), max(vals)
@@ -18,7 +32,7 @@ class Line(BaseGraph):
 
     def _plot(self):
         for serie in self.series:
-            self.svg.line(
-                self.svg.serie(serie.index), [
+            self.line(
+                self._serie(serie.index), [
                 (self._x_pos[i], v)
                 for i, v in enumerate(serie.values)])
diff --git a/pygal/graph/pie.py b/pygal/graph/pie.py
index f095364..f3b0a84 100644
--- a/pygal/graph/pie.py
+++ b/pygal/graph/pie.py
@@ -1,11 +1,36 @@
 from pygal.serie import Serie
-from pygal.graph.base import BaseGraph
-from math import pi
+from pygal.graph.graph import Graph
+from math import cos, sin, pi
 
 
-class Pie(BaseGraph):
+class Pie(Graph):
     """Pie graph"""
 
+    def slice(self, serie_node, start_angle, angle, perc):
+        slices = self.svg.node(serie_node, class_="slices")
+        slice_ = self.svg.node(slices, class_="slice")
+        center = ((self.width - self.margin.x) / 2.,
+                  (self.height - self.margin.y) / 2.)
+        r = min(center)
+        center_str = '%f %f' % center
+        rxy = '%f %f' % tuple([r] * 2)
+        to = '%f %f' % (r * sin(angle), r * (1 - cos(angle)))
+        self.svg.node(slice_, 'path',
+                  d='M%s v%f a%s 0 %d 1 %s z' % (
+                      center_str, -r,
+                      rxy,
+                      1 if angle > pi else 0,
+                      to),
+                  transform='rotate(%f %s)' % (
+                      start_angle * 180 / pi, center_str),
+                  class_='slice')
+        text_angle = pi / 2. - (start_angle + angle / 2.)
+        text_r = min(center) * .8
+        self.svg.node(slice_, 'text',
+                  x=center[0] + text_r * cos(text_angle),
+                  y=center[1] - text_r * sin(text_angle),
+              ).text = '{:.2%}'.format(perc)
+
     def add(self, title, value):
         self.series.append(Serie(title, [value], len(self.series)))
 
@@ -15,8 +40,8 @@ class Pie(BaseGraph):
         for serie in self.series:
             val = serie.values[0]
             angle = 2 * pi * val / total
-            self.svg.slice(
-                self.svg.serie(serie.index),
+            self.slice(
+                self._serie(serie.index),
                 current_angle,
                 angle, val / total)
             current_angle += angle
diff --git a/pygal/graph/radar.py b/pygal/graph/radar.py
index a97a818..159111f 100644
--- a/pygal/graph/radar.py
+++ b/pygal/graph/radar.py
@@ -1,27 +1,81 @@
-from pygal.graph.base import BaseGraph
-from math import pi
+from pygal.graph.line import Line
+from pygal.view import PolarView
+from pygal.util import deg
+from math import cos, sin, pi
 
 
-class Radar(BaseGraph):
+class Radar(Line):
     """Kiviat graph"""
 
+    def _set_view(self):
+        self.view = PolarView(
+            self.width - self.margin.x,
+            self.height - self.margin.y,
+            self._box)
+
+    def _x_axis(self):
+        if not self._x_labels:
+            return
+
+        axis = self.svg.node(self.plot, class_="axis x web")
+        format = lambda x: '%f %f' % x
+        center = self.view((0, 0))
+        r = self._rmax
+        for label, theta in self._x_labels:
+            guides = self.svg.node(axis, class_='guides')
+            end = self.view((r, theta))
+            self.svg.node(guides, 'path',
+                      d='M%s L%s' % (format(center), format(end)),
+                      class_='line')
+            r_txt = (1 - self._box.__class__._margin) * self._box.ymax
+            pos_text = self.view((r_txt, theta))
+            text = self.svg.node(guides, 'text',
+                      x=pos_text[0],
+                      y=pos_text[1]
+            )
+            text.text = label
+            angle = - theta + pi / 2.
+            if cos(angle) < 0:
+                angle -= pi
+            text.attrib['transform'] = 'rotate(%f %s)' % (
+                deg(angle), format(pos_text))
+
+    def _y_axis(self):
+        if not self._y_labels:
+            return
+
+        axis = self.svg.node(self.plot, class_="axis y web")
+
+        for label, r in reversed(self._y_labels):
+            guides = self.svg.node(axis, class_='guides')
+            self.svg.line(
+                guides, [self.view((r, theta)) for theta in self._x_pos],
+                close=True,
+                class_='guide line')
+            x, y = self.view((r, self._x_pos[0]))
+            self.svg.node(guides, 'text',
+                             x=x - 5,
+                             y=y
+            ).text = label
+
     def _compute(self):
         vals = [val for serie in self.series for val in serie.values]
-        self._box.ymax = 2 * max(vals)
-        self._box.ymin = - self._box.ymax
-        self._box.xmin = self._box.ymin
-        self._box.xmax = self._box.ymax
+        self._box._margin *= 2
+        self._box.xmin = self._box.ymin = 0
+        self._box.xmax = self._box.ymax = self._rmax = max(vals)
 
-        delta = 2 * pi / float(len(self.x_labels))
         x_step = len(self.series[0].values)
+        delta = 2 * pi / float(len(self.x_labels))
         self._x_pos = [.5 * pi - i * delta for i in range(x_step)]
         self._y_pos = self._pos(self._box.ymin, self._box.ymax, self.y_scale
         ) if not self.y_labels else map(int, self.y_labels)
         self._x_labels = self.x_labels and zip(self.x_labels, self._x_pos)
         self._y_labels = zip(map(str, self._y_pos), self._y_pos)
+        self._box.xmin = self._box.ymin = - self._box.ymax
 
     def _plot(self):
         for serie in self.series:
-            serie_node = self.svg.serie(serie.index)
-            # self.svg.web(serie_node, serie,
-                         # [val / float(self._rmax) for val in serie.values])
+            serie_node = self._serie(serie.index)
+            self.line(serie_node, [
+                     (v, self._x_pos[i])
+                     for i, v in enumerate(serie.values)])
diff --git a/pygal/graph/stackedbar.py b/pygal/graph/stackedbar.py
index 5329231..51bba91 100644
--- a/pygal/graph/stackedbar.py
+++ b/pygal/graph/stackedbar.py
@@ -1,7 +1,7 @@
-from pygal.graph.base import BaseGraph
+from pygal.graph.bar import Bar
 
 
-class StackedBar(BaseGraph):
+class StackedBar(Bar):
     """Stacked Bar graph"""
 
     def _compute(self):
@@ -29,8 +29,8 @@ class StackedBar(BaseGraph):
     def _plot(self):
         stack_vals = [[0, 0] for i in range(self._length)]
         for serie in self.series:
-            serie_node = self.svg.serie(serie.index)
-            stack_vals = self.svg.bar(
+            serie_node = self._serie(serie.index)
+            stack_vals = self.bar(
                 serie_node, serie, [
                 tuple((self._x_ranges[i][j], v) for j in range(2))
                 for i, v in enumerate(serie.values)],
diff --git a/pygal/graph/xy.py b/pygal/graph/xy.py
index 406308d..f72083c 100644
--- a/pygal/graph/xy.py
+++ b/pygal/graph/xy.py
@@ -1,9 +1,12 @@
-from pygal.graph.base import BaseGraph
+from pygal.graph.line import Line
 
 
-class XY(BaseGraph):
+class XY(Line):
     """XY Line graph"""
 
+    def _get_value(self, values, i):
+        return str(values[i])
+
     def _compute(self):
         for serie in self.series:
             serie.values = sorted(serie.values, key=lambda x: x[0])
@@ -20,5 +23,5 @@ class XY(BaseGraph):
 
     def _plot(self):
         for serie in self.series:
-            self.svg.line(
-                self.svg.serie(serie.index), serie.values, True)
+            self.line(
+                self._serie(serie.index), serie.values)
diff --git a/pygal/style.py b/pygal/style.py
index c2c279c..1991da8 100644
--- a/pygal/style.py
+++ b/pygal/style.py
@@ -6,6 +6,7 @@ class Style(object):
         foreground_light='#eee',
         foreground_dark='#555',
         opacity='.8',
+        opacity_hover='1',
         transition='250ms',
         colors=(
                 '#ff5995', '#b6e354', '#feed6c', '#8cedff', '#9e6ffe',
@@ -18,6 +19,7 @@ class Style(object):
             self.foreground_light = foreground_light
             self.foreground_dark = foreground_dark
             self.opacity = opacity
+            self.opacity_hover = opacity_hover
             self.transition = transition
             self._colors = colors
 
@@ -43,6 +45,7 @@ LightStyle = Style(
             '#77bbb5', '#777777'))
 NeonStyle = Style(
     opacity='.1',
+    opacity_hover='.75',
     transition='1s ease-out')
 
 styles = {'default': DefaultStyle,
diff --git a/pygal/svg.py b/pygal/svg.py
index 2820ac8..41f4363 100644
--- a/pygal/svg.py
+++ b/pygal/svg.py
@@ -1,8 +1,7 @@
 # -*- coding: utf-8 -*-
 import os
 from lxml import etree
-from pygal.view import View
-from pygal.util import template, swap, ident
+from pygal.util import template
 from math import cos, sin, pi
 
 
@@ -34,7 +33,11 @@ class Svg(object):
                 f.read(),
                 style=self.graph.style,
                 font_sizes=self.graph.font_sizes,
-                hidden='y' if self.graph.horizontal else 'x')
+                hidden='y' if self.graph.horizontal else 'x',
+                fill_opacity=self.graph.style.opacity
+                if self.graph.fill else 0,
+                fill_opacity_hover=self.graph.style.opacity_hover
+                if self.graph.fill else 0)
 
     def node(self, parent=None, tag='g', attrib=None, **extras):
         if parent is None:
@@ -59,241 +62,15 @@ class Svg(object):
                 extras[key1], extras[key2] = attr2, attr1
         return self.node(parent, tag, attrib, **extras)
 
-    def set_view(self):
-        self.view = View(
-            self.graph.width - self.graph.margin.x,
-            self.graph.height - self.graph.margin.y,
-            self.graph._box)
+    def format(self, xy):
+        return '%f %f' % xy
 
-    def make_graph(self):
-        self.graph_node = self.node(
-            class_='graph %s' % self.graph.__class__.__name__)
-        self.node(self.graph_node, 'rect',
-                  class_='background',
-                  x=0, y=0,
-                  width=self.graph.width,
-                  height=self.graph.height)
-        self.plot = self.node(
-            self.graph_node, class_="plot",
-            transform="translate(%d, %d)" % (
-                self.graph.margin.left, self.graph.margin.top))
-        self.node(self.plot, 'rect',
-                  class_='background',
-                  x=0, y=0,
-                  width=self.view.width,
-                  height=self.view.height)
-
-    def x_axis(self):
-        if not self.graph._x_labels:
-            return
-
-        axis = self.node(self.plot, class_="axis x")
-
-        if 0 not in [label[1] for label in self.graph._x_labels]:
-            self.node(axis, 'path',
-                      d='M%f %f v%f' % (0, 0, self.view.height),
-                      class_='line')
-        for label, position in self.graph._x_labels:
-            guides = self.node(axis, class_='guides')
-            x = self.view.x(position)
-            y = self.view.height + 5
-            self.node(guides, 'path',
-                      d='M%f %f v%f' % (x, 0, self.view.height),
-                    class_='%sline' % (
-                        'guide ' if position != 0 else ''))
-            text = self.node(guides, 'text',
-                             x=x,
-                             y=y + .5 * self.graph.label_font_size + 5)
-            if self.graph.x_label_rotation:
-                text.attrib['transform'] = "rotate(%d %f %f)" % (
-                    self.graph.x_label_rotation, x, y)
-            text.text = label
-
-    def y_axis(self):
-        if not self.graph._y_labels:
-            return
-
-        axis = self.node(self.plot, class_="axis y")
-
-        if 0 not in [label[1] for label in self.graph._y_labels]:
-            self.node(axis, 'path',
-                      d='M%f %f h%f' % (0, self.view.height, self.view.width),
-                      class_='line')
-        for label, position in self.graph._y_labels:
-            guides = self.node(axis, class_='guides')
-            x = -5
-            y = self.view.y(position)
-            self.node(guides, 'path',
-                      d='M%f %f h%f' % (0, y, self.view.width),
-                      class_='%sline' % (
-                          'guide ' if position != 0 else ''))
-            text = self.node(guides, 'text',
-                             x=x,
-                             y=y + .35 * self.graph.label_font_size)
-            if self.graph.y_label_rotation:
-                text.attrib['transform'] = "rotate(%d %f %f)" % (
-                    self.graph.y_label_rotation, x, y)
-            text.text = label
-
-    def web_axis(self):
-        axis = self.node(self.plot, class_="axis polar")
-        delta = 2 * pi / float(len(self.graph.x_labels))
-        center = self.view((0, 0))
-        f = lambda x: '%f %f' % x
-        for i, title in enumerate(self.graph.x_labels):
-            angle = .5 * pi - i * delta
-            end = self.view((cos(angle), sin(angle)))
-            self.node(axis, 'path',
-                      d='M%s L%s' % (f(center), f(end)),
-                      class_='line')
-            self.node(axis, 'text',
-                      x=end[0],
-                      y=end[1]
-            ).text = str(i)
-
-    def legend(self):
-        if not self.graph.show_legend:
-            return
-        legends = self.node(
-            self.graph_node, class_='legends',
-            transform='translate(%d, %d)' % (
-                self.graph.margin.left + self.view.width + 10,
-                self.graph.margin.top + 10))
-        for i, title in enumerate(self.graph._legends):
-            legend = self.node(legends, class_='legend')
-            self.node(legend, 'rect',
-                      x=0,
-                      y=1.5 * i * self.graph.legend_box_size,
-                      width=self.graph.legend_box_size,
-                      height=self.graph.legend_box_size,
-                      class_="color-%d" % i,
-                  ).text = title
-            # Serious magical numbers here
-            self.node(legend, 'text',
-                      x=self.graph.legend_box_size + 5,
-                      y=1.5 * i * self.graph.legend_box_size
-                      + .5 * self.graph.legend_box_size
-                      + .3 * self.graph.legend_font_size
-            ).text = title
-
-    def title(self):
-        if self.graph.title:
-            self.node(self.graph_node, 'text', class_='title',
-                      x=self.graph.margin.left + self.view.width / 2,
-                      y=self.graph.title_font_size + 10
-            ).text = self.graph.title
-
-    def serie(self, serie):
-        return self.node(
-            self.plot, class_='series serie-%d color-%d' % (serie, serie))
-
-    def line(self, serie_node, values, xy=False):
-        view_values = map(self.view, values)
-        origin = '%f %f' % view_values[0]
-
-        dots = self.node(serie_node, class_="dots")
-        for i, (x, y) in enumerate(view_values):
-            dot = self.node(dots, class_='dot')
-            self.node(dot, 'circle', cx=x, cy=y, r=2.5)
-            self.node(dot, 'text', x=x, y=y).text = str(
-                values[i]) if xy else str(values[i][1])
-
-        svg_values = ' '.join(map(lambda x: '%f %f' % x, view_values))
-        self.node(serie_node, 'path',
-                  d='M%s L%s' % (origin, svg_values), class_='line')
-
-    def bar(self, serie_node, serie, values, stack_vals=None):
-        """Draw a bar graph for a serie"""
-        # value here is a list of tuple range of tuple coord
-
-        def view(rng):
-            """Project range"""
-            t, T = rng
-            fun = swap if self.graph.horizontal else ident
-            return (self.view(fun(t)), self.view(fun(T)))
-
-        bars = self.node(serie_node, class_="bars")
-        view_values = map(view, values)
-        for i, ((x, y), (X, Y)) in enumerate(view_values):
-            # x and y are left range coords and X, Y right ones
-            if self.graph.horizontal:
-                x, y, X, Y = Y, X, y, x
-            width = X - x
-            padding = .1 * width
-            inner_width = width - 2 * padding
-            if self.graph.horizontal:
-                height = self.view.x(0) - y
-            else:
-                height = self.view.y(0) - y
-            if stack_vals == None:
-                bar_width = inner_width / len(self.graph.series)
-                bar_padding = .1 * bar_width
-                bar_inner_width = bar_width - 2 * bar_padding
-                offset = serie.index * bar_width + bar_padding
-                shift = 0
-            else:
-                offset = 0
-                bar_inner_width = inner_width
-                shift = stack_vals[i][int(height < 0)]
-                stack_vals[i][int(height < 0)] += height
-            x = x + padding + offset
-
-            if height < 0:
-                y = y + height
-                height = -height
-
-            y_txt = y + height / 2 + .3 * self.graph.values_font_size
-            bar = self.node(bars, class_='bar')
-            self.transposable_node(bar, 'rect',
-                      x=x,
-                      y=y - shift,
-                      rx=self.graph.rounded_bars * 1,
-                      ry=self.graph.rounded_bars * 1,
-                      width=bar_inner_width,
-                      height=height,
-                      class_='rect')
-            self.transposable_node(bar, 'text',
-                      x=x + bar_inner_width / 2,
-                      y=y_txt - shift,
-            ).text = str(values[i][1][1])
-        return stack_vals
-
-    def slice(self, serie_node, start_angle, angle, perc):
-        slices = self.node(serie_node, class_="slices")
-        slice_ = self.node(slices, class_="slice")
-        center = ((self.graph.width - self.graph.margin.x) / 2.,
-                  (self.graph.height - self.graph.margin.y) / 2.)
-        r = min(center)
-        center_str = '%f %f' % center
-        rxy = '%f %f' % tuple([r] * 2)
-        to = '%f %f' % (r * sin(angle), r * (1 - cos(angle)))
-        self.node(slice_, 'path',
-                  d='M%s v%f a%s 0 %d 1 %s z' % (
-                      center_str, -r,
-                      rxy,
-                      1 if angle > pi else 0,
-                      to),
-                  transform='rotate(%f %s)' % (
-                      start_angle * 180 / pi, center_str),
-                  class_='slice')
-        text_angle = pi / 2. - (start_angle + angle / 2.)
-        text_r = min(center) * .8
-        self.node(slice_, 'text',
-                  x=center[0] + text_r * cos(text_angle),
-                  y=center[1] - text_r * sin(text_angle),
-              ).text = '{:.2%}'.format(perc)
-
-    def web(self, serie_node, serie, radius):
-        webs = self.node(serie_node, class_="webs")
-        web = self.node(webs, class_="web")
-        # view_radius = map(self.view, radius)
-        origin = '%f %f' % self.view((0, 0))
-        dot1 = '%f %f' % self.view((1, 1))
-        dot2 = '%f %f' % self.view((-1, -1))
-        self.node(web, 'path',
-                  d='M%s L%s %s' % (
-                      origin, dot1, dot2),
-                  class_='web')
+    def line(self, node, coords, close=False, **kwargs):
+        root = 'M%s L%s Z' if close else 'M%s L%s'
+        origin = self.format(coords[0])
+        line = ' '.join(map(self.format, coords[1:]))
+        self.node(node, 'path',
+                  d=root % (origin, line), **kwargs)
 
     def render(self):
         return etree.tostring(
diff --git a/pygal/util.py b/pygal/util.py
index 7007e3d..2699a44 100644
--- a/pygal/util.py
+++ b/pygal/util.py
@@ -32,6 +32,10 @@ def rad(deg):
     return pi * deg / 180.
 
 
+def deg(deg):
+    return 180 * deg / pi
+
+
 def _swap_curly(string):
     """Swap single and double curly brackets"""
     return (string
diff --git a/pygal/view.py b/pygal/view.py
index 1eee897..1060370 100644
--- a/pygal/view.py
+++ b/pygal/view.py
@@ -1,3 +1,6 @@
+from math import sin, cos
+
+
 class Margin(object):
     def __init__(self, top, right, bottom, left):
         self.top = top
@@ -64,3 +67,10 @@ class View(object):
     def __call__(self, xy):
         x, y = xy
         return (self.x(x), self.y(y))
+
+
+class PolarView(View):
+    def __call__(self, rtheta):
+        r, theta = rtheta
+        return super(PolarView, self).__call__(
+            (r * cos(theta), r * sin(theta)))