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 try:
  25     from .diagram import Diagram
  26 except ValueError:
  27     from diagram import Diagram
  28
  29
  30 class InkscapeDrawing(svgwrite.Drawing):
  31     """An svgwrite.Drawing subclass which supports Inkscape layers"""
  32     def __init__(self, *args, **kwargs):
  33         super(InkscapeDrawing, self).__init__(*args, **kwargs)
  34
  35         inkscape_attributes = {
  36             'xmlns:inkscape': SVGAttribute('xmlns:inkscape',
  37                                            anim=False,
  38                                            types=[],
  39                                            const=frozenset(['http://www.inkscape.org/namespaces/inkscape'])),
  40             'inkscape:groupmode': SVGAttribute('inkscape:groupmode',
  41                                                anim=False,
  42                                                types=[],
  43                                                const=frozenset(['layer'])),
  44             'inkscape:label': SVGAttribute('inkscape:label',
  45                                            anim=False,
  46                                            types=frozenset(['string']),
  47                                            const=[])
  48         }
  49
  50         self.validator.attributes.update(inkscape_attributes)
  51
  52         elements = self.validator.elements
  53
  54         svg_attributes = set(elements['svg'].valid_attributes)
  55         svg_attributes.add('xmlns:inkscape')
  56         elements['svg'].valid_attributes = frozenset(svg_attributes)
  57
  58         g_attributes = set(elements['g'].valid_attributes)
  59         g_attributes.add('inkscape:groupmode')
  60         g_attributes.add('inkscape:label')
  61         elements['g'].valid_attributes = frozenset(g_attributes)
  62
  63         self['xmlns:inkscape'] = 'http://www.inkscape.org/namespaces/inkscape'
  64
  65     def layer(self, **kwargs):
  66         """Create an inkscape layer.
  67
  68         An optional 'label' keyword argument can be passed to set a user
  69         friendly name for the layer."""
  70         label = kwargs.pop('label', None)
  71
  72         new_layer = self.g(**kwargs)
  73         new_layer['inkscape:groupmode'] = 'layer'
  74
  75         if label:
  76             new_layer['inkscape:label'] = label
  77
  78         return new_layer
  79
  80
  81 class SvgwriteDiagram(Diagram):
  82     def __init__(self, width, height, **kwargs):
  83         super(SvgwriteDiagram, self).__init__(width, height, **kwargs)
  84
  85         self.svg = InkscapeDrawing(None, profile='full', size=(str(width) + "px", str(height) + "px"))
  86         self.active_group = self.svg
  87
  88     def clear(self):
  89         # Reset the SVG object
  90         self.svg.elements = []
  91         self.svg.add(self.svg.defs)
  92
  93         rect = self.svg.rect((0, 0), ('100%', '100%'))
  94         self._fill(rect, self.background)
  95         self.svg.add(rect)
  96
  97     def save_svg(self, filename):
  98         self.svg.saveas(filename)
  99
 100     def add(self, element):
 101         self.active_group.add(element)
 102
 103     def color_to_rgba(self, color):
 104         color = super(SvgwriteDiagram, self).color_to_rgba(color)
 105
 106         return color[0] * 255, color[1] * 255, color[2] * 255, color[3]
 107
 108     def _fill(self, element, fill_color):
 109         if fill_color:
 110             r, g, b, a = self.color_to_rgba(fill_color)
 111             fill_color = svgwrite.utils.rgb(r, g, b, mode='RGB')
 112             element['fill'] = fill_color
 113             element['fill-opacity'] = a
 114         else:
 115             element['fill'] = 'none'
 116
 117     def _stroke(self, element, stroke_color):
 118         if stroke_color:
 119             r, g, b, a = self.color_to_rgba(stroke_color)
 120             stroke_color = svgwrite.utils.rgb(r, g, b, mode='RGB')
 121             element['stroke'] = stroke_color
 122             element['stroke-opacity'] = a
 123             element['stroke-linejoin'] = 'round'
 124             element['stroke-width'] = self.stroke_width
 125         else:
 126             element['stroke'] = 'none'
 127
 128     def draw_polygon_by_verts(self, verts,
 129                               stroke_color=(0, 0, 0),
 130                               fill_color=None):
 131         polygon = self.svg.polygon(verts)
 132
 133         self._fill(polygon, fill_color)
 134         self._stroke(polygon, stroke_color)
 135
 136         self.add(polygon)
 137
 138     def draw_star_by_verts(self, cx, cy, verts, stroke_color=(0, 0, 0)):
 139         for v in verts:
 140             line = self.svg.line((cx, cy), v)
 141             self._stroke(line, stroke_color)
 142             self.add(line)
 143
 144     def draw_circle(self, cx, cy, radius=10.0,
 145                     stroke_color=None,
 146                     fill_color=(0, 0, 0, 0.5)):
 147         circle = self.svg.circle((cx, cy), radius)
 148
 149         self._fill(circle, fill_color)
 150         self._stroke(circle, stroke_color)
 151
 152         self.add(circle)
 153
 154     def draw_line(self, x1, y1, x2, y2, stroke_color=(0, 0, 0, 1)):
 155         line = self.svg.line((x1, y1), (x1, y2))
 156         self._stroke(line, stroke_color)
 157
 158         self.add(line)
 159
 160     def draw_rect(self, x, y, width, height, theta=0,
 161                   stroke_color=None,
 162                   fill_color=(1, 1, 1, 0.8)):
 163         rect = self.svg.rect((x, y), (width, height))
 164
 165         rect['transform'] = 'rotate(%f, %f, %f)' % (degrees(theta), x, y)
 166
 167         self._fill(rect, fill_color)
 168         self._stroke(rect, stroke_color)
 169
 170         self.add(rect)
 171
 172     def draw_centered_text(self, cx, cy, text, theta=0.0,
 173                            color=(0, 0, 0),
 174                            align_baseline=False,
 175                            bb_stroke_color=None,
 176                            bb_fill_color=None):
 177
 178         # Using font_size to calculate dy is not optimal as the font _height_ may
 179         # be different from the font_size, but it's better than nothing.
 180         text_element = self.svg.text(text, x=[cx], y=[cy], dy=[self.font_size / 2.])
 181         self._fill(text_element, color)
 182         text_element['font-size'] = self.font_size
 183         text_element['text-anchor'] = 'middle'
 184         text_element['transform'] = 'rotate(%f, %f, %f)' % (degrees(theta), cx, cy)
 185         self.add(text_element)
 186
 187         if align_baseline:
 188             warnings.warn("The align_baseline option has not been implemented yet.")
 189
 190         if bb_stroke_color or bb_fill_color:
 191             warnings.warn("Drawing the bounding box has not been implemented yet.")
 192
 193         # XXX: this is just a very quick and dirty estimate to advance the text
 194         return self.font_size * len(text) / 2
 195
 196
 197 def test():
 198     diagram = SvgwriteDiagram(400, 400)
 199
 200     Diagram.test(diagram)
 201
 202     diagram.save_svg('svgwrite_diagram_test.svg')
 203
 204
 205 if __name__ == "__main__":
 206     test()