Source code for pygal.graph.histogram

# -*- coding: utf-8 -*-
# This file is part of pygal
# A python svg graph plotting library
# Copyright © 2012-2016 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 <>.
Histogram chart: like a bar chart but with data plotted along a x axis
as bars of varying width.

from __future__ import division

from import Bar
from pygal.graph.dual import Dual
from pygal.util import alter, cached_property, decorate

[docs]class Histogram(Dual, Bar): """Histogram chart class""" _series_margin = 0 @cached_property def _values(self): """Getter for secondary series values (flattened)""" return self.yvals @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
[docs] def xvals(self): """All x values""" return [val for serie in self.all_series for dval in serie.values for val in dval[1:3] if val is not None]
[docs] def yvals(self): """All y values""" return [val[0] for serie in self.series for val in serie.values if val[0] is not None]
def _bar(self, serie, parent, x0, x1, y, i, zero, secondary=False): """Internal bar drawing function""" 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 = serie.rounded_bars * 1 if serie.rounded_bars else 0 alter(self.svg.transposable_node( parent, 'rect', x=x, y=y, rx=r, ry=r, width=width, height=height, class_='rect reactive tooltip-trigger'), serie.metadata.get(i)) return x, y, width, height
[docs] def bar(self, serie, rescale=False): """Draw a bar graph for a serie""" serie_node = self.svg.serie(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, i) bounds = self._bar( serie, bar, x0, x1, y, i,, secondary=rescale) self._tooltip_and_print_values( serie_node, serie, bar, i, val, metadata, *bounds)
def _compute(self): """Compute x/y min and max and x/y scale and set labels""" 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), ymax = max(max(self.yvals), 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 if self.range and self.range[0] is not None: self._box.ymin = self.range[0] if self.range and self.range[1] is not None: self._box.ymax = self.range[1]