114 lines
4.8 KiB
Python
114 lines
4.8 KiB
Python
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#!/usr/bin/env python3
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#
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# Copyright (C) 2016 Kie Brooks
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# Distributed under GPLv3 or later.
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# draw_ratchet
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# version 0.1
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#
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# This file is part of draw_ratchet
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#
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# draw_ratchet 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 3 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, see <http://www.gnu.org/licenses/>.
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#
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#
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# description :
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# draw ratchet gears to arbitrary sizes and precision
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#
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# I am not an engineer, I am sure this little program could be improved or made much more complex,
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# it may contain horrible flaws but it fills my current need and should be easy to improve on.
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# Alternatively pay me some money and I might do it for you ;P
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#
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# This program is used by inkscape.
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# It can be found in the menu : extensions -> render -> ratchet
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# see file draw_ratch.inx
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# (directory ~/.config/inkscape/extensions/)
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import inkex
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import math
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from lxml import etree
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def draw_SVG_circle(parent, r, cx, cy, name, style):
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" structure an SVG circle entity under parent "
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circ_attribs = {'style': str(inkex.Style(style)),
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'cx': str(cx), 'cy': str(cy),
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'r': str(r),
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inkex.addNS('label','inkscape'): name}
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circle = etree.SubElement(parent, inkex.addNS('circle','svg'), circ_attribs )
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class Ratchet(inkex.EffectExtension):
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def add_arguments(self, pars):
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pars.add_argument("--centre_hole", type=inkex.Boolean, default=True, help="Show or not")
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pars.add_argument("--teeth", type=int, default=12, help="Number of teeth around outside")
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pars.add_argument("--centre_hole_diam", type=float, default=1, help="Dia of central hole")
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pars.add_argument("--diam_in", type=float, default=28, help="Inner diamter of the Ratchet")
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pars.add_argument("--diam_out", type=float, default=30, help="Outer diamter of the Ratchet")
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pars.add_argument('--vtooth_shape', default='straight', help="Shape of tooth")
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pars.add_argument('--htooth_shape', default='curve', help="Shape of tooth")
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def effect(self):
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Line_style = {'stroke':'#000000','stroke-width':self.svg.unittouu(str(0.1) + "mm"),'fill':'none'}
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# sort out the options
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teeth = self.options.teeth
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diam_in = self.options.diam_in
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diam_out = self.options.diam_out
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vtooth_shape = self.options.vtooth_shape
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htooth_shape = self.options.htooth_shape
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# Create group center of view
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t = 'translate(%s,%s)' % (self.svg.namedview.center[0], self.svg.namedview.center[1])
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grp_attribs = {inkex.addNS('label','inkscape'):'Ratchet', 'transform':t}
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grp = etree.SubElement(self.svg.get_current_layer(), 'g', grp_attribs)
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#
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# Central hole (at origin)
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if self.options.centre_hole:
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draw_SVG_circle(grp, self.options.centre_hole_diam, 0,0, 'Central_hole', Line_style)
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#Polygon drawing
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# <path d="M50,50 A30,50 0 0,1 100,100"
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# style="stroke:#660000; fill:none;"/>
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# L - line : x posn, y posn
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# A - arc : radius x, radius y, x-axis rotation, large arc flag, sweep flag
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# Points on the ratchet
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# b
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# |\
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# | \ |\
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# \ | \ | \
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# \ | \| \
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# a c \
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path = "M%s %s " %(diam_in,0)
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for i in range(teeth):
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angle = math.radians(i * 360/ teeth)
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x_a = diam_in * math.cos(angle)
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y_a = diam_in * math.sin(angle)
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x_b = diam_out * math.cos(angle)
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y_b = diam_out * math.sin(angle)
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if vtooth_shape == "straight":
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path += ' L %s %s ' %(x_b, y_b)
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else:
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path += " A %s,%s 0 0 0 %s %s" % (diam_in, diam_in, x_b, y_b)
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#
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angle_next = math.radians((i+1) * 360 / teeth)
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x_c = diam_in * math.cos(angle_next)
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y_c = diam_in * math.sin(angle_next)
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if htooth_shape == "straight":
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path += ' L %s %s ' %(x_c, y_c)
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else: # Arc
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path += " A %s,%s 0 0 1 %s %s" % (diam_in, diam_in, x_c, y_c)
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# close path
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path += 'z'
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# draw it
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line_attribs = {'style' : str(inkex.Style(Line_style)), inkex.addNS('label','inkscape') : 'Cone' }
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line_attribs['d'] = path
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etree.SubElement(grp, inkex.addNS('path','svg'), line_attribs )
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if __name__ == "__main__":
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Ratchet().run()
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