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Diffstat (limited to 'share/extensions/spirograph.py')
| -rwxr-xr-x | share/extensions/spirograph.py | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/share/extensions/spirograph.py b/share/extensions/spirograph.py new file mode 100755 index 0000000..5d7dcf4 --- /dev/null +++ b/share/extensions/spirograph.py @@ -0,0 +1,102 @@ +#! /usr/bin/env python +# coding=utf-8 +# +# Copyright (C) 2007 Joel Holdsworth joel@airwebreathe.org.uk +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program 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 General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. +# + +import math +import inkex + +class Spirograph(inkex.EffectExtension): + def add_arguments(self, pars): + pars.add_argument("--primaryr", type=float, default=60.0, + help="The radius of the outer gear") + pars.add_argument("--secondaryr", type=float, default=100.0, + help="The radius of the inner gear") + pars.add_argument("--penr", type=float, default=50.0, + help="The distance of the pen from the inner gear") + pars.add_argument("--gearplacement", default="inside", + help="Selects whether the gear is inside or outside the ring") + pars.add_argument("--rotation", type=float, default=0.0, + help="The number of degrees to rotate the image by") + pars.add_argument("--quality", type=int, default=16, + help="The quality of the calculated output") + + def effect(self): + self.options.primaryr = self.svg.unittouu(str(self.options.primaryr) + 'px') + self.options.secondaryr = self.svg.unittouu(str(self.options.secondaryr) + 'px') + self.options.penr = self.svg.unittouu(str(self.options.penr) + 'px') + + if self.options.secondaryr == 0: + return + if self.options.quality == 0: + return + + if self.options.gearplacement.strip(' ').lower().startswith('outside'): + a = self.options.primaryr + self.options.secondaryr + flip = -1 + else: + a = self.options.primaryr - self.options.secondaryr + flip = 1 + + ratio = a / self.options.secondaryr + if ratio == 0: + return + scale = 2 * math.pi / (ratio * self.options.quality) + + rotation = - math.pi * self.options.rotation / 180 + + new = inkex.PathElement() + new.style = inkex.Style(stroke='#000000', fill='none', stroke_width='1.0') + + path_string = '' + maxPointCount = 1000 + + for i in range(maxPointCount): + + theta = i * scale + + view_center = self.svg.namedview.center + x = a * math.cos(theta + rotation) + \ + self.options.penr * math.cos(ratio * theta + rotation) * flip + \ + view_center[0] + y = a * math.sin(theta + rotation) - \ + self.options.penr * math.sin(ratio * theta + rotation) + \ + view_center[1] + + dx = (-a * math.sin(theta + rotation) - ratio * self.options.penr * math.sin(ratio * theta + rotation) * flip) * scale / 3 + dy = (a * math.cos(theta + rotation) - ratio * self.options.penr * math.cos(ratio * theta + rotation)) * scale / 3 + + if i <= 0: + path_string += 'M {},{} C {},{} '.format(str(x), str(y), str(x + dx), str(y + dy)) + else: + path_string += '{},{} {},{}'.format(str(x - dx), str(y - dy), str(x), str(y)) + + if math.fmod(i / ratio, self.options.quality) == 0 and i % self.options.quality == 0: + path_string += 'Z' + break + else: + if i == maxPointCount - 1: + pass # we reached the allowed maximum of points, stop here + else: + path_string += ' C {},{} '.format(str(x + dx), str(y + dy)) + + new.path = path_string + self.svg.get_current_layer().append(new) + +if __name__ == '__main__': + Spirograph().run() |