Add gauge

demo/simple_test.py

@@ -26,6 +26,13 @@ lnk = lambda v, l=None: {'value': v, 'xlink': 'javascript:alert("Test %s")' % v,
 
 t_start  = time.time()
 
+gauge = Gauge()
+
+gauge.range = [-10, 10]
+gauge.add('Need l', [2.3, 5.12])
+# gauge.add('No', [99, -99])
+gauge.render_to_file('out-gauge.svg')
+
 pyramid = Pyramid()
 
 pyramid.x_labels = ['0-25', '25-45', '45-65', '65+']
@@ -168,6 +175,7 @@ pie.add('test3', [24, 10, 32])
 pie.add('test4', [20, lnk(18), 9])
 pie.add('test5', [17, 5, 10])
 pie.add('test6', [None, None, 10])
+
 # pie.included_js = []
 # pie.external_js = [
 #     'http://localhost:7575/svg.jquery.js',

pygal/__init__.py

@@ -26,11 +26,12 @@ __version__ = '0.9.22'
 from pygal.config import Config
 from pygal.graph.bar import Bar
 from pygal.graph.dot import Dot
+from pygal.graph.funnel import Funnel
+from pygal.graph.gauge import Gauge
 from pygal.graph.horizontal import HorizontalBar
 from pygal.graph.horizontal import HorizontalStackedBar
 from pygal.graph.line import Line
 from pygal.graph.pie import Pie
-from pygal.graph.funnel import Funnel
 from pygal.graph.pyramid import Pyramid
 from pygal.graph.radar import Radar
 from pygal.graph.stackedbar import StackedBar
@@ -41,8 +42,9 @@ from pygal.graph.xy import XY
 #: List of all chart types
 CHARTS = [
     Bar,
-    Funnel,
     Dot,
+    Funnel,
+    Gauge,
     HorizontalBar,
     HorizontalStackedBar,
     Line,

pygal/config.py

@@ -87,6 +87,8 @@ class Config(object):
     interpolate = None
     #: Number of interpolated points between two values
     interpolation_precision = 250
+    #: Explicitly specify min and max of values (ie: (0, 100))
+    range = None
     #: Set the ordinate zero value (for filling)
     zero = 0
     #: Text to display when no data is given

pygal/css/graph.css

@@ -72,6 +72,7 @@ text.no_data {
 
 .axis.y .guides:hover .guide.line,
 .line-graph .axis.x .guides:hover .guide.line,
+.gauge-graph .axis.x .guides:hover .guide.line,
 .stackedline-graph .axis.x .guides:hover .guide.line,
 .xy-graph .axis.x .guides:hover .guide.line {
   opacity: 1;

pygal/graph/base.py

@@ -128,12 +128,12 @@ class BaseGraph(object):
     @cached_property
     def _min(self):
         """Getter for the minimum series value"""
-        return min(self._values)
+        return (self.range and self.range[0]) or min(self._values)
 
     @cached_property
     def _max(self):
         """Getter for the maximum series value"""
-        return max(self._values)
+        return (self.range and self.range[1]) or max(self._values)
 
     def _draw(self):
         """Draw all the things"""

pygal/graph/gauge.py

@@ -0,0 +1,122 @@
+# -*- coding: utf-8 -*-
+# This file is part of pygal
+#
+# A python svg graph plotting library
+# Copyright © 2012 Kozea
+#
+# This library is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your option) any
+# later version.
+#
+# This library is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with pygal. If not, see <http://www.gnu.org/licenses/>.
+"""
+Gauge chart
+
+"""
+
+from __future__ import division
+from pygal.util import decorate, compute_scale
+from pygal.view import PolarView
+from pygal.graph.graph import Graph
+from math import pi
+
+
+class Gauge(Graph):
+    """Gauge graph"""
+
+    def _set_view(self):
+        self.view = PolarView(
+            self.width - self.margin.x,
+            self.height - self.margin.y,
+            self._box)
+
+    def arc_pos(self, value):
+        aperture = pi / 3
+        if value > self._max:
+            return (3 * pi - aperture / 2) / 2
+        if value < self._min:
+            return (3 * pi + aperture / 2) / 2
+        start = 3 * pi / 2 + aperture / 2
+        return start + (2 * pi - aperture) * (
+            value - self.min_) / (self.max_ - self.min_)
+
+    def needle(self, serie_node, serie,):
+        thickness = .05
+        for i, value in enumerate(serie.values):
+            theta = self.arc_pos(value)
+            fmt = lambda x: '%f %f' % x
+            value = self._format(serie.values[i])
+            metadata = serie.metadata[i]
+            gauges = decorate(
+                self.svg,
+                self.svg.node(serie_node['plot'], class_="dots"),
+                metadata)
+
+            self.svg.node(gauges, 'polygon', points=' '.join([
+                fmt(self.view((0, 0))),
+                fmt(self.view((.75, theta + thickness))),
+                fmt(self.view((.8, theta))),
+                fmt(self.view((.75, theta - thickness)))]),
+                          class_='line reactive tooltip-trigger')
+
+            x, y = self.view((.75, theta))
+            self._tooltip_data(gauges, value, x, y)
+            self._static_value(serie_node, value, x, y)
+
+    def _x_axis(self, draw_axes=True):
+        if not self._x_labels:
+            return
+
+        axis = self.svg.node(self.nodes['plot'], class_="axis x gauge")
+
+        for i, (label, pos) in enumerate(self._x_labels):
+            guides = self.svg.node(axis, class_='guides')
+            theta = self.arc_pos(pos)
+            self.svg.line(
+                guides, [self.view((.95, theta)), self.view((1, theta))],
+                close=True,
+                class_='line')
+
+            self.svg.line(
+                guides, [self.view((0, theta)), self.view((.95, theta))],
+                close=True,
+                class_='guide line %s' % ('major'
+                if i in (0, len(self._x_labels) - 1) else ''))
+
+            x, y = self.view((.9, theta))
+            self.svg.node(guides, 'text',
+                          x=x,
+                          y=y
+                      ).text = label
+
+    def _y_axis(self, draw_axes=True):
+        axis = self.svg.node(self.nodes['plot'], class_="axis y gauge")
+        x, y = self.view((0, 0))
+        self.svg.node(axis, 'circle', cx=x, cy=y, r=4)
+
+    def _compute(self):
+        self._box.xmin = -1
+        self._box.ymin = -1
+
+        self.min_ = self._min
+        self.max_ = self._max
+        if self.max_ - self.min_ == 0:
+            self.min_ -= 1
+            self.max_ += 1
+
+        x_pos = compute_scale(
+            self.min_, self.max_, self.logarithmic
+        )
+        self._x_labels = zip(map(self._format, x_pos), x_pos)
+
+    def _plot(self):
+        for serie in self.series:
+            self.needle(
+                self._serie(serie.index), serie)

pygal/graph/pie.py

@@ -35,6 +35,7 @@ class Pie(Graph):
 
     def slice(self, serie_node, start_angle, serie, total):
         """Make a serie slice"""
+        dual = self._len > 1 and not len(self.series) == 1
 
         slices = self.svg.node(serie_node['plot'], class_="slices")
         serie_angle = 0
@@ -53,18 +54,20 @@ class Pie(Graph):
                 self.svg,
                 self.svg.node(slices, class_="slice"),
                 metadata)
-            if len(serie.values) > 1:
+            if dual:
                 small_radius = radius * .9
+                big_radius = radius
             else:
-                radius = radius * .9
+                big_radius = radius * .9
                 small_radius = 0
 
-            self.svg.slice(serie_node,
+            self.svg.slice(
-                slice_, radius, small_radius, angle, start_angle, center, val)
+                serie_node, slice_, big_radius, small_radius,
+                angle, start_angle, center, val)
             start_angle += angle
             total_perc += perc
 
-        if len(serie.values) > 1:
+        if dual:
             val = '{0:.2%}'.format(total_perc)
             self.svg.slice(serie_node,
                            self.svg.node(slices, class_="big_slice"),