src/svg_hexaflexagon_editor.py

   1 #!/usr/bin/env python3
   2 #
   3 # Draw an SVG hexaflexagon which can be edited live in Inkscape.
   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 svgwrite
  21
  22 from diagram.svgwrite_diagram import SvgwriteDiagram
  23 from flexagon.hexaflexagon_diagram import HexaflexagonDiagram
  24
  25
  26 class SvgwriteHexaflexagonDiagram(HexaflexagonDiagram):
  27     def __init__(self, *args, **kwargs):
  28         super(SvgwriteHexaflexagonDiagram, self).__init__(*args, **kwargs)
  29
  30         svg = self.backend.svg
  31
  32         # create some layers and groups
  33         layers = {
  34             "Hexagons": svg.layer(label="Hexagons"),
  35             "Backfaces": svg.layer(label="Backfaces"),
  36             "Hexaflexagon": svg.layer(label="Hexaflexagon"),
  37             "Folding guide": svg.layer(label="Folding guide"),
  38             "Template": svg.layer(label="Template")
  39         }
  40         for layer in layers.values():
  41             svg.add(layer)
  42
  43         self.groups = layers
  44
  45         for hexagon in self.hexaflexagon.hexagons:
  46             name = "hexagon%d-content" % hexagon.index
  47             layer = svg.layer(id=name, label="Hexagon %d" % (hexagon.index + 1))
  48             self.groups[name] = layer
  49             layers['Hexagons'].add(layer)
  50
  51             for triangle in hexagon.triangles:
  52                 name = "hexagon%d-triangle%d" % (hexagon.index, triangle.index)
  53                 group = svg.g(id=name)
  54                 self.groups[name] = group
  55                 layers['Template'].add(group)
  56
  57     def draw(self):
  58         for hexagon in self.hexaflexagon.hexagons:
  59             cx, cy = self.get_hexagon_center(hexagon)
  60
  61             # Draw some default content
  62             old_active_group = self.backend.active_group
  63             self.backend.active_group = self.groups["hexagon%d-content" % hexagon.index]
  64             self.backend.draw_regular_polygon(cx, cy, 6, self.hexagon_radius,
  65                                               stroke_color=None,
  66                                               fill_color=(0.5, 0.5, 0.5, 0.2))
  67             self.backend.active_group = old_active_group
  68
  69             # Add folding guides
  70             old_active_group = self.backend.active_group
  71             self.backend.active_group = self.groups["Folding guide"]
  72
  73             for triangle in hexagon.triangles:
  74                 cx, cy = self.get_triangle_center(triangle)
  75                 theta = triangle.get_angle_in_hexagon()
  76                 self.backend.draw_regular_polygon(cx, cy, 3, self.triangle_radius, theta,
  77                                                   stroke_color=(0, 0, 0, 0.2),
  78                                                   fill_color=None)
  79                 polygon = self.backend.active_group.elements[-1]
  80                 polygon['id'] = "hexagon%d-triangle%d-folding" % (triangle.hexagon.index,
  81                                                                   triangle.index)
  82
  83             self.backend.active_group = old_active_group
  84
  85         # Draw the normal template for hexagons
  86         for hexagon in self.hexaflexagon.hexagons:
  87             self.draw_hexagon_template(hexagon)
  88
  89         # draw plan using references
  90         for hexagon in self.hexaflexagon.hexagons:
  91             for triangle in hexagon.triangles:
  92                 m = self.get_triangle_transform(triangle)
  93                 svg_matrix = "matrix(%f, %f, %f, %f, %f, %f)" % (m[0], m[3],
  94                                                                  m[1], m[4],
  95                                                                  m[2], m[5])
  96
  97                 # Reuse the hexagons triangle for the hexaflexagon template
  98                 group = self.groups["Template"]
  99                 triangle_href = "#hexagon%d-triangle%d" % (hexagon.index, triangle.index)
 100                 ref = self.backend.svg.use(triangle_href)
 101                 ref['transform'] = svg_matrix
 102                 group.add(ref)
 103
 104                 # Reuse the folding guides
 105                 group = self.groups["Folding guide"]
 106                 folding_href = "#hexagon%d-triangle%d-folding" % (hexagon.index, triangle.index)
 107                 ref = self.backend.svg.use(folding_href)
 108                 ref['transform'] = svg_matrix
 109                 group.add(ref)
 110
 111                 # Reuse the content to draw the final hexaflexagon
 112                 group = self.groups["Hexaflexagon"]
 113                 content_href = "#hexagon%d-content" % hexagon.index
 114                 ref = self.backend.svg.use(content_href)
 115                 ref['transform'] = svg_matrix
 116                 ref['clip-path'] = "url(%s)" % (triangle_href + '-clip-path')
 117                 group.add(ref)
 118
 119         # draw the backfaces
 120         group = self.groups["Backfaces"]
 121         for hexagon in self.hexaflexagon.hexagons:
 122             for triangle in hexagon.triangles:
 123                 m = self.get_triangle_backfaces_transform(triangle)
 124                 svg_matrix = "matrix(%f, %f, %f, %f, %f, %f)" % (m[0], m[3],
 125                                                                  m[1], m[4],
 126                                                                  m[2], m[5])
 127
 128                 triangle_href = "#hexagon%d-triangle%d" % (hexagon.index, triangle.index)
 129
 130                 # Reuse the content to draw the backface
 131                 content_href = "#hexagon%d-content" % hexagon.index
 132                 ref = self.backend.svg.use(content_href)
 133                 ref['transform'] = svg_matrix
 134                 ref['clip-path'] = "url(%s)" % (triangle_href + '-clip-path')
 135                 group.add(ref)
 136
 137     def draw_triangle_template(self, triangle, cx, cy, theta):
 138         old_active_group = self.backend.active_group
 139         group_name = "hexagon%d-triangle%d" % (triangle.hexagon.index, triangle.index)
 140         self.backend.active_group = self.groups[group_name]
 141
 142         super(SvgwriteHexaflexagonDiagram, self).draw_triangle_template(triangle, cx, cy, theta)
 143
 144         # The triangle outline in the active group's element is the only polygon
 145         # element, so get it and set its id so that it can be reused as
 146         # a clip-path
 147         for element in self.backend.active_group.elements:
 148             if isinstance(element, svgwrite.shapes.Polygon):
 149                 element['id'] = group_name + "-outline"
 150                 break
 151
 152         clip_path = self.backend.svg.clipPath(id=group_name + '-clip-path')
 153         self.backend.svg.defs.add(clip_path)
 154         ref = self.backend.svg.use('#%s-outline' % group_name)
 155         clip_path.add(ref)
 156
 157         self.backend.active_group = old_active_group
 158
 159
 160 def main():
 161     width = 3508
 162     height = 2480
 163
 164     x_border = width / 50
 165     font_size = width / 80
 166     stroke_width = width / 480
 167
 168     svg_backend = SvgwriteDiagram(width, height, font_size=font_size, stroke_width=stroke_width)
 169     hexaflexagon = SvgwriteHexaflexagonDiagram(x_border, backend=svg_backend)
 170     hexaflexagon.draw()
 171     svg_backend.save_svg("inkscape-hexaflexagon-editor.svg")
 172
 173
 174 if __name__ == "__main__":
 175     main()