88 lines
2.7 KiB
Python
Executable file
88 lines
2.7 KiB
Python
Executable file
#!/usr/bin/env python3
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#
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# Copyright (C) 2013 Brett Graham (hahahaha @ hahaha.org)
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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#
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"""
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Generate a gear rack as SVG.
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"""
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from math import acos, cos, radians, sin, sqrt, tan
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import inkex
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def involute_intersect_angle(Rb, R):
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Rb, R = float(Rb), float(R)
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return (sqrt(R**2 - Rb**2) / Rb) - (acos(Rb / R))
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def point_on_circle(radius, angle):
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x = radius * cos(angle)
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y = radius * sin(angle)
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return x, y
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def points_to_svgd(p):
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"""
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p: list of 2 tuples (x, y coordinates)
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"""
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f = p[0]
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p = p[1:]
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svgd = "M{:.3f},{:.3f}".format(f[0], f[1])
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for x in p:
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svgd += "L{:.3f},{:.3f}".format(x[0], x[1])
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return svgd
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class RackGear(inkex.GenerateExtension):
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container_label = "Rendered Gear Rack"
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def add_arguments(self, pars):
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pars.add_argument("--length", type=float, default=100.0, help="Rack Length")
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pars.add_argument("--spacing", type=float, default=10.0, help="Tooth Spacing")
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pars.add_argument("--angle", type=float, default=20.0, help="Contact Angle")
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def generate(self):
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length = self.svg.unittouu(str(self.options.length) + "px")
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spacing = self.svg.unittouu(str(self.options.spacing) + "px")
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angle = radians(self.options.angle)
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# generate points: list of (x, y) pairs
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points = []
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x = 0
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tas = tan(angle) * spacing
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while x < length:
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# move along path, generating the next 'tooth'
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points.append((x, 0))
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points.append((x + tas, spacing))
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points.append((x + spacing, spacing))
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points.append((x + spacing + tas, 0))
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x += spacing * 2.0
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path = points_to_svgd(points)
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# Create SVG Path for gear
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style = {
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"stroke": "#000000",
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"fill": "none",
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"stroke-width": str(self.svg.unittouu("1px")),
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}
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yield inkex.PathElement(style=str(inkex.Style(style)), d=str(path))
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if __name__ == "__main__":
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RackGear().run()
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