Add histogram chart type. Fixes #48

demo/moulinrouge/tests.py

@@ -2,7 +2,7 @@
 # This file is part of pygal
 from pygal import (
     Bar, Gauge, Pyramid, Funnel, Dot, StackedBar, XY,
-    CHARTS_BY_NAME, Config, Line, DateY, Worldmap)
+    CHARTS_BY_NAME, Config, Line, DateY, Worldmap, Histogram)
 from pygal.style import styles
 
 
@@ -217,6 +217,18 @@ def get_test_routes(app):
         bar.add('2', [4, 5, 6])
         return bar.render_response()
 
+    @app.route('/test/histogram')
+    def test_histogram():
+        hist = Histogram(style=styles['neon'])
+        hist.add('1', [
+            (2, 0, 1),
+            (4, 1, 3),
+            (3, 3.5, 5),
+            (1.5, 5, 10)
+        ])
+        hist.add('2', [(2, 2, 8)])
+        return hist.render_response()
+
     @app.route('/test/secondary/<chart>')
     def test_secondary_for(chart):
         chart = CHARTS_BY_NAME[chart](fill=True)

pygal/graph/__init__.py

@@ -37,5 +37,6 @@ CHARTS_NAMES = [
     'Dot',
     'Gauge',
     'DateY',
-    'Worldmap'
+    'Worldmap',
+    'Histogram'
 ]

pygal/graph/histogram.py

@@ -0,0 +1,148 @@
+# -*- coding: utf-8 -*-
+# This file is part of pygal
+#
+# A python svg graph plotting library
+# Copyright © 2012-2013 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/>.
+"""
+Histogram chart
+
+"""
+
+from __future__ import division
+from pygal.graph.graph import Graph
+from pygal.util import swap, ident, compute_scale, decorate, cached_property
+
+
+class Histogram(Graph):
+    """Histogram chart"""
+
+    _dual = True
+    _series_margin = 0
+    _serie_margin = 0
+
+    @cached_property
+    def _values(self):
+        """Getter for secondary series values (flattened)"""
+        return [val[0]
+                for serie in self.series
+                for val in serie.values
+                if val[0] is not None]
+
+    @cached_property
+    def _secondary_values(self):
+        """Getter for secondary series values (flattened)"""
+        return [val[0]
+                for serie in self.secondary_series
+                for val in serie.values
+                if val[0] is not None]
+
+    @cached_property
+    def xvals(self):
+        return [val
+                for serie in self.all_series
+                for dval in serie.values
+                for val in dval[1:3]
+                if val is not None]
+
+    @cached_property
+    def yvals(self):
+        return [val[0]
+                for serie in self.series
+                for val in serie.values
+                if val[0] is not None]
+
+    def _has_data(self):
+        """Check if there is any data"""
+        return sum(
+            map(len, map(lambda s: s.safe_values, self.series))) != 0 and any((
+                sum(map(abs, self.xvals)) != 0,
+                sum(map(abs, self.yvals)) != 0))
+
+    def _bar(self, parent, x0, x1, y, index, i, zero, secondary=False):
+        x, y = self.view((x0, y))
+        x1, _ = self.view((x1, y))
+        width = x1 - x
+        height = self.view.y(zero) - y
+        series_margin = width * self._series_margin
+        x += series_margin
+        width -= 2 * series_margin
+
+        r = self.rounded_bars * 1 if self.rounded_bars else 0
+        self.svg.transposable_node(
+            parent, 'rect',
+            x=x, y=y, rx=r, ry=r, width=width, height=height,
+            class_='rect reactive tooltip-trigger')
+        transpose = swap if self.horizontal else ident
+        return transpose((x + width / 2, y + height / 2))
+
+    def bar(self, serie_node, serie, index, rescale=False):
+        """Draw a bar graph for a serie"""
+        bars = self.svg.node(serie_node['plot'], class_="histbars")
+        points = serie.points
+
+        for i, (y, x0, x1) in enumerate(points):
+            if None in (x0, x1, y) or (self.logarithmic and y <= 0):
+                continue
+            metadata = serie.metadata.get(i)
+
+            bar = decorate(
+                self.svg,
+                self.svg.node(bars, class_='histbar'),
+                metadata)
+            val = self._format(serie.values[i][0])
+
+            x_center, y_center = self._bar(
+                bar, x0, x1, y, index, i, self.zero, secondary=rescale)
+            self._tooltip_data(
+                bar, val, x_center, y_center, classes="centered")
+            self._static_value(serie_node, val, x_center, y_center)
+
+    def _compute(self):
+        if self.xvals:
+            xmin = min(self.xvals)
+            xmax = max(self.xvals)
+            xrng = (xmax - xmin)
+        else:
+            xrng = None
+
+        if self.yvals:
+            ymin = min(min(self.yvals), self.zero)
+            ymax = max(max(self.yvals), self.zero)
+            yrng = (ymax - ymin)
+        else:
+            yrng = None
+
+        for serie in self.all_series:
+            serie.points = serie.values
+
+        if xrng:
+            self._box.xmin, self._box.xmax = xmin, xmax
+        if yrng:
+            self._box.ymin, self._box.ymax = ymin, ymax
+
+        x_pos = compute_scale(
+            self._box.xmin, self._box.xmax, self.logarithmic, self.order_min)
+        y_pos = compute_scale(
+            self._box.ymin, self._box.ymax, self.logarithmic, self.order_min)
+
+        self._x_labels = list(zip(map(self._format, x_pos), x_pos))
+        self._y_labels = list(zip(map(self._format, y_pos), y_pos))
+
+    def _plot(self):
+        for index, serie in enumerate(self.series):
+            self.bar(self._serie(index), serie, index)
+        for index, serie in enumerate(self.secondary_series, len(self.series)):
+            self.bar(self._serie(index), serie, index, True)

pygal/graph/xy.py

@@ -51,9 +51,6 @@ class XY(Line):
                 sum(map(abs, self.xvals)) != 0,
                 sum(map(abs, self.yvals)) != 0))
 
-    def _get_value(self, values, i):
-        return 'x=%s, y=%s' % tuple(map(self._format, values[i]))
-
     def _compute(self):
         if self.xvals:
             xmin = min(self.xvals)
@@ -92,9 +89,9 @@ class XY(Line):
                 xrng = None
 
         if xrng:
-            self._box.xmin, self._box.xmax = min(self.xvals), max(self.xvals)
+            self._box.xmin, self._box.xmax = xmin, xmax
         if yrng:
-            self._box.ymin, self._box.ymax = min(self.yvals), max(self.yvals)
+            self._box.ymin, self._box.ymax = ymin, ymax
 
         x_pos = compute_scale(
             self._box.xmin, self._box.xmax, self.logarithmic, self.order_min)

pygal/util.py

@@ -298,6 +298,7 @@ from pygal.serie import Serie
 def prepare_values(raw, config, cls):
     """Prepare the values to start with sane values"""
     from pygal.graph.datey import DateY
+    from pygal.graph.histogram import Histogram
     from pygal.graph.worldmap import Worldmap
     if config.x_labels is None and hasattr(cls, 'x_labels'):
         config.x_labels = cls.x_labels
@@ -350,7 +351,14 @@ def prepare_values(raw, config, cls):
             else:
                 value = raw_value
 
-            if cls._dual:
+            # Fix this by doing this in charts class methods
+            if issubclass(cls, Histogram):
+                if value is None:
+                    value = (None, None, None)
+                elif not hasattr(value, '__iter__'):
+                    value = (value, config.zero, config.zero)
+                value = list(map(adapter, value))
+            elif cls._dual:
                 if value is None:
                     value = (None, None)
                 elif not hasattr(value, '__iter__'):