pygal/pygal/svg.py

# -*- coding: utf-8 -*-
# This file is part of pygal
#
# A python svg graph plotting library
# Copyright © 2012-2015 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/>.

"""Svg helper"""

from __future__ import division
from pygal._compat import to_str, u, quote_plus
from pygal.etree import etree
import io
import os
import json
from datetime import date, datetime
from numbers import Number
from math import cos, sin, pi
from pygal.util import template, minify_css
from pygal import __version__


class Svg(object):

    """Svg related methods"""

    ns = 'http://www.w3.org/2000/svg'
    xlink_ns = 'http://www.w3.org/1999/xlink'

    def __init__(self, graph):
        """Create the svg helper with the chart instance"""
        self.graph = graph
        if not graph.no_prefix:
            self.id = '#chart-%s ' % graph.uuid
        else:
            self.id = ''
        self.processing_instructions = []
        if etree.lxml:
            attrs = {
                'nsmap': {
                    None: self.ns,
                    'xlink': self.xlink_ns
                }
            }
        else:
            attrs = {
                'xmlns': self.ns
            }
            if hasattr(etree, 'register_namespace'):
                etree.register_namespace('xlink', self.xlink_ns)
            else:
                etree._namespace_map[self.xlink_ns] = 'xlink'

        self.root = etree.Element('svg', **attrs)
        self.root.attrib['id'] = self.id.lstrip('#').rstrip()
        self.root.attrib['class'] = 'pygal-chart'
        self.root.append(
            etree.Comment(u(
                'Generated with pygal %s (%s) ©Kozea 2011-2015 on %s' % (
                    __version__,
                    'lxml' if etree.lxml else 'etree',
                    date.today().isoformat()))))
        self.root.append(etree.Comment(u('http://pygal.org')))
        self.root.append(etree.Comment(u('http://github.com/Kozea/pygal')))
        self.defs = self.node(tag='defs')
        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)
        strokes = self.get_strokes()
        all_css = []
        auto_css = ['file://base.css']

        if self.graph.style._google_fonts:
            auto_css.append(
                '//fonts.googleapis.com/css?family=%s' % quote_plus(
                    '|'.join(self.graph.style._google_fonts))
            )

        for css in auto_css + list(self.graph.css):
            css_text = None
            if css.startswith('inline:'):
                css_text = css[len('inline:'):]
            elif css.startswith('file://'):
                if not os.path.exists(css):
                    css = os.path.join(
                        os.path.dirname(__file__), 'css', css[len('file://'):])

                with io.open(css, encoding='utf-8') as f:
                    css_text = template(
                        f.read(),
                        style=self.graph.style,
                        colors=colors,
                        strokes=strokes,
                        id=self.id)

            if css_text is not None:
                if not self.graph.pretty_print:
                    css_text = minify_css(css_text)
                all_css.append(css_text)
            else:
                if css.startswith('//') and self.graph.force_uri_protocol:
                    css = '%s:%s' % (self.graph.force_uri_protocol, css)
                self.processing_instructions.append(
                    etree.PI(
                        u('xml-stylesheet'), u('href="%s"' % css)))
        self.node(
            self.defs, 'style', type='text/css').text = '\n'.join(all_css)

    def add_scripts(self):
        """Add the js to the svg"""
        common_script = self.node(self.defs, 'script', type='text/javascript')

        def get_js_dict():
            return dict(
                (k, getattr(self.graph.state, k))
                for k in dir(self.graph.config)
                if not k.startswith('_') and hasattr(self.graph.state, k) and
                not hasattr(getattr(self.graph.state, k), '__call__'))

        def json_default(o):
            if isinstance(o, (datetime, date)):
                return o.isoformat()
            if hasattr(o, 'to_dict'):
                return o.to_dict()
            return json.JSONEncoder().default(o)

        dct = get_js_dict()
        # Config adds
        dct['legends'] = [
            l.get('title') if isinstance(l, dict) else l
            for l in self.graph._legends + self.graph._secondary_legends]

        common_js = 'window.pygal = window.pygal || {};'
        common_js += 'window.pygal.config = window.pygal.config || {};'
        if self.graph.no_prefix:
            common_js += 'window.pygal.config = '
        else:
            common_js += 'window.pygal.config[%r] = ' % self.graph.uuid

        common_script.text = common_js + json.dumps(dct, default=json_default)

        for js in self.graph.js:
            if js.startswith('file://'):
                script = self.node(self.defs, 'script', type='text/javascript')
                with io.open(js[len('file://'):], encoding='utf-8') as f:
                    script.text = f.read()
            else:
                if js.startswith('//') and self.graph.force_uri_protocol:
                    js = '%s:%s' % (self.graph.force_uri_protocol, js)
                self.node(self.defs, 'script', type='text/javascript', href=js)

    def node(self, parent=None, tag='g', attrib=None, **extras):
        """Make a new svg node"""
        if parent is None:
            parent = self.root
        attrib = attrib or {}
        attrib.update(extras)

        def in_attrib_and_number(key):
            return key in attrib and isinstance(attrib[key], Number)

        for pos, dim in (('x', 'width'), ('y', 'height')):
            if in_attrib_and_number(dim) and attrib[dim] < 0:
                attrib[dim] = - attrib[dim]
                if in_attrib_and_number(pos):
                    attrib[pos] = attrib[pos] - attrib[dim]

        for key, value in dict(attrib).items():
            if value is None:
                del attrib[key]

            attrib[key] = to_str(value)
            if key.endswith('_'):
                attrib[key.rstrip('_')] = attrib[key]
                del attrib[key]
            elif key == 'href':
                attrib[etree.QName(
                    'http://www.w3.org/1999/xlink',  key)] = attrib[key]
                del attrib[key]
        return etree.SubElement(parent, tag, attrib)

    def transposable_node(self, parent=None, tag='g', attrib=None, **extras):
        """Make a new svg node which can be transposed if horizontal"""
        if self.graph.horizontal:
            for key1, key2 in (('x', 'y'), ('width', 'height'), ('cx', 'cy')):
                attr1 = extras.get(key1, None)
                attr2 = extras.get(key2, None)
                if attr2:
                    extras[key1] = attr2
                elif attr1:
                    del extras[key1]
                if attr1:
                    extras[key2] = attr1
                elif attr2:
                    del extras[key2]
        return self.node(parent, tag, attrib, **extras)

    def serie(self, serie):
        """Make serie node"""
        return dict(
            plot=self.node(
                self.graph.nodes['plot'],
                class_='series serie-%d color-%d' % (
                    serie.index, serie.index)),
            overlay=self.node(
                self.graph.nodes['overlay'],
                class_='series serie-%d color-%d' % (
                    serie.index, serie.index)),
            text_overlay=self.node(
                self.graph.nodes['text_overlay'],
                class_='series serie-%d color-%d' % (
                    serie.index, serie.index)))

    def line(self, node, coords, close=False, **kwargs):
        """Draw a svg line"""
        line_len = len(coords)
        if line_len < 2:
            return
        root = 'M%s L%s Z' if close else 'M%s L%s'
        origin_index = 0
        while origin_index < line_len and None in coords[origin_index]:
            origin_index += 1
        if origin_index == line_len:
            return
        if self.graph.horizontal:
            coord_format = lambda xy: '%f %f' % (xy[1], xy[0])
        else:
            coord_format = lambda xy: '%f %f' % xy

        origin = coord_format(coords[origin_index])
        line = ' '.join([coord_format(c)
                         for c in coords[origin_index + 1:]
                         if None not in c])
        return self.node(
            node, 'path', d=root % (origin, line), **kwargs)

    def slice(
            self, serie_node, node, radius, small_radius,
            angle, start_angle, center, val, i, metadata):
        """Draw a pie slice"""
        project = lambda rho, alpha: (
            rho * sin(-alpha), rho * cos(-alpha))
        diff = lambda x, y: (x[0] - y[0], x[1] - y[1])
        fmt = lambda x: '%f %f' % x
        get_radius = lambda r: fmt(tuple([r] * 2))
        absolute_project = lambda rho, theta: fmt(
            diff(center, project(rho, theta)))

        if angle == 2 * pi:
            rv = self.node(
                node, 'circle',
                cx=center[0],
                cy=center[1],
                r=radius,
                class_='slice reactive tooltip-trigger')
        elif angle > 0:
            to = [absolute_project(radius, start_angle),
                  absolute_project(radius, start_angle + angle),
                  absolute_project(small_radius, start_angle + angle),
                  absolute_project(small_radius, start_angle)]
            rv = self.node(
                node, 'path',
                d='M%s A%s 0 %d 1 %s L%s A%s 0 %d 0 %s z' % (
                    to[0],
                    get_radius(radius), int(angle > pi), to[1],
                    to[2],
                    get_radius(small_radius), int(angle > pi), to[3]),
                class_='slice reactive tooltip-trigger')
        else:
            rv = None
        x, y = diff(center, project(
            (radius + small_radius) / 2, start_angle + angle / 2))

        self.graph._tooltip_data(
            node, val, x, y, "centered",
            self.graph._x_labels and self.graph._x_labels[i][0])
        if angle >= 0.3:  # 0.3 radians is about 17 degrees
            self.graph._static_value(serie_node, val, x, y, metadata)
        return rv

    def pre_render(self):
        """Last things to do before rendering"""
        self.add_styles()
        self.add_scripts()
        self.root.set(
            'viewBox', '0 0 %d %d' % (self.graph.width, self.graph.height))
        if self.graph.explicit_size:
            self.root.set('width', str(self.graph.width))
            self.root.set('height', str(self.graph.height))

    def draw_no_data(self):
        """Write the no data text to the svg"""
        no_data = self.node(self.graph.nodes['text_overlay'], 'text',
                            x=self.graph.view.width / 2,
                            y=self.graph.view.height / 2,
                            class_='no_data')
        no_data.text = self.graph.no_data_text

    def render(self, is_unicode=False, pretty_print=False):
        """Last thing to do before rendering"""
        for f in self.graph.xml_filters:
            self.root = f(self.root)
        args = {
            'encoding': 'utf-8'
        }

        svg = b''
        if etree.lxml:
            args['pretty_print'] = pretty_print

        if not self.graph.disable_xml_declaration:
            svg = b"<?xml version='1.0' encoding='utf-8'?>\n"

        if not self.graph.disable_xml_declaration:
            svg += b'\n'.join(
                [etree.tostring(
                    pi, **args)
                 for pi in self.processing_instructions]
            )

        svg += etree.tostring(
            self.root, **args)

        if self.graph.disable_xml_declaration or is_unicode:
            svg = svg.decode('utf-8')
        return svg

    def get_strokes(self):
        """Return a css snippet containing all stroke style options"""
        def stroke_dict_to_css(stroke, i=None):
            """Return a css style for the given option"""
            css = ['%s.series%s {\n' % (
                self.id, '.serie-%d' % i if i is not None else '')]
            for key in (
                    'width', 'linejoin', 'linecap',
                    'dasharray', 'dashoffset'):
                if stroke.get(key):
                    css.append('  stroke-%s: %s;\n' % (
                        key, stroke[key]))
            css.append('}')
            return '\n'.join(css)

        css = []
        if self.graph.stroke_style is not None:
            css.append(stroke_dict_to_css(self.graph.stroke_style))
        for serie in self.graph.series:
            if serie.stroke_style is not None:
                css.append(stroke_dict_to_css(serie.stroke_style, serie.index))
        return '\n'.join(css)