src/diagram/svgwrite_diagram.py

   1 #!/usr/bin/env python
   2 #
   3 # A Diagram abstraction based on svgwrite
   4 #
   5 # Copyright (C) 2018  Antonio Ospite <ao2@ao2.it>
   6 #
   7 # This program is free software: you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation, either version 3 of the License, or
  10 # (at your option) any later version.
  11 #
  12 # This program is distributed in the hope that it will be useful,
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 # GNU General Public License for more details.
  16 #
  17 # You should have received a copy of the GNU General Public License
  18 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19
  20 import warnings
  21 from math import degrees
  22 import svgwrite
  23 from svgwrite.data.types import SVGAttribute
  24 from .diagram import Diagram
  25
  26
  27 class InkscapeDrawing(svgwrite.Drawing):
  28     """An svgwrite.Drawing subclass which supports Inkscape layers"""
  29     def __init__(self, *args, **kwargs):
  30         super(InkscapeDrawing, self).__init__(*args, **kwargs)
  31
  32         inkscape_attributes = {
  33             'xmlns:inkscape': SVGAttribute('xmlns:inkscape',
  34                                            anim=False,
  35                                            types=[],
  36                                            const=frozenset(['http://www.inkscape.org/namespaces/inkscape'])),
  37             'inkscape:groupmode': SVGAttribute('inkscape:groupmode',
  38                                                anim=False,
  39                                                types=[],
  40                                                const=frozenset(['layer'])),
  41             'inkscape:label': SVGAttribute('inkscape:label',
  42                                            anim=False,
  43                                            types=frozenset(['string']),
  44                                            const=[])
  45         }
  46
  47         self.validator.attributes.update(inkscape_attributes)
  48
  49         elements = self.validator.elements
  50
  51         svg_attributes = set(elements['svg'].valid_attributes)
  52         svg_attributes.add('xmlns:inkscape')
  53         elements['svg'].valid_attributes = frozenset(svg_attributes)
  54
  55         g_attributes = set(elements['g'].valid_attributes)
  56         g_attributes.add('inkscape:groupmode')
  57         g_attributes.add('inkscape:label')
  58         elements['g'].valid_attributes = frozenset(g_attributes)
  59
  60         self['xmlns:inkscape'] = 'http://www.inkscape.org/namespaces/inkscape'
  61
  62     def layer(self, **kwargs):
  63         """Create an inkscape layer.
  64
  65         An optional 'label' keyword argument can be passed to set a user
  66         friendly name for the layer."""
  67         label = kwargs.pop('label', None)
  68
  69         new_layer = self.g(**kwargs)
  70         new_layer['inkscape:groupmode'] = 'layer'
  71
  72         if label:
  73             new_layer['inkscape:label'] = label
  74
  75         return new_layer
  76
  77
  78 class SvgwriteDiagram(Diagram):
  79     def __init__(self, width, height, **kwargs):
  80         super(SvgwriteDiagram, self).__init__(width, height, **kwargs)
  81
  82         self.svg = InkscapeDrawing(None, profile='full', size=(str(width) + "px", str(height) + "px"))
  83         self.active_group = self.svg
  84
  85     def clear(self):
  86         # Reset the SVG object
  87         self.svg.elements = []
  88         self.svg.add(self.svg.defs)
  89
  90         rect = self.svg.rect((0, 0), ('100%', '100%'))
  91         self._fill(rect, self.background)
  92         self.svg.add(rect)
  93
  94     def save_svg(self, filename):
  95         self.svg.saveas(filename)
  96
  97     def add(self, element):
  98         self.active_group.add(element)
  99
 100     def color_to_rgba(self, color):
 101         color = super(SvgwriteDiagram, self).color_to_rgba(color)
 102
 103         return color[0] * 255, color[1] * 255, color[2] * 255, color[3]
 104
 105     def _fill(self, element, fill_color):
 106         if fill_color:
 107             r, g, b, a = self.color_to_rgba(fill_color)
 108             fill_color = svgwrite.utils.rgb(r, g, b, mode='RGB')
 109             element['fill'] = fill_color
 110             element['fill-opacity'] = a
 111         else:
 112             element['fill'] = 'none'
 113
 114     def _stroke(self, element, stroke_color):
 115         if stroke_color:
 116             r, g, b, a = self.color_to_rgba(stroke_color)
 117             stroke_color = svgwrite.utils.rgb(r, g, b, mode='RGB')
 118             element['stroke'] = stroke_color
 119             element['stroke-opacity'] = a
 120             element['stroke-linejoin'] = 'round'
 121         else:
 122             element['stroke'] = 'none'
 123
 124     def draw_polygon_by_verts(self, verts,
 125                               stroke_color=(0, 0, 0),
 126                               fill_color=None):
 127         polygon = self.svg.polygon(verts, stroke_width=self.stroke_width)
 128
 129         self._fill(polygon, fill_color)
 130         self._stroke(polygon, stroke_color)
 131
 132         self.add(polygon)
 133
 134     def draw_star_by_verts(self, cx, cy, verts, stroke_color=(0, 0, 0)):
 135         for v in verts:
 136             line = self.svg.line((cx, cy), v, stroke_width=self.stroke_width)
 137             self._stroke(line, stroke_color)
 138             self.add(line)
 139
 140     def draw_centered_text(self, cx, cy, text, theta=0.0,
 141                            color=(0, 0, 0),
 142                            align_baseline=False,
 143                            bb_stroke_color=None,
 144                            bb_fill_color=None):
 145
 146         # Using font_size to calculate dy is not optimal as the font _height_ may
 147         # be different from the font_size, but it's better than nothing.
 148         text_element = self.svg.text(text, x=[cx], y=[cy], dy=[self.font_size / 2.])
 149         self._fill(text_element, color)
 150         text_element['font-size'] = self.font_size
 151         text_element['text-anchor'] = 'middle'
 152         text_element['transform'] = 'rotate(%f, %f, %f)' % (degrees(theta), cx, cy)
 153         self.add(text_element)
 154
 155         if align_baseline:
 156             warnings.warn("The align_baseline option has not been implemented yet.")
 157
 158         if bb_stroke_color or bb_fill_color:
 159             warnings.warn("Drawing the bounding box has not been implemented yet.")