#!/usr/bin/env python
'''
Copyright (C) 2013 Brett Graham (hahahaha @ hahaha.org)
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 inkex
import simplestyle
from simpletransform import computePointInNode
from math import *
def involute_intersect_angle(Rb, R):
Rb, R = float(Rb), float(R)
return (sqrt(R**2 - Rb**2) / (Rb)) - (acos(Rb / R))
def point_on_circle(radius, angle):
x = radius * cos(angle)
y = radius * sin(angle)
return (x, y)
def points_to_svgd(p):
"""
p: list of 2 tuples (x, y coordinates)
"""
f = p[0]
p = p[1:]
svgd = 'M%.3f,%.3f' % f
for x in p:
svgd += 'L%.3f,%.3f' % x
return svgd
class RackGear(inkex.Effect):
def __init__(self):
inkex.Effect.__init__(self)
self.OptionParser.add_option(
"-l", "--length",
action="store", type="float",
dest="length", default=100.,
help="Rack Length")
self.OptionParser.add_option(
"-s", "--spacing",
action="store", type="float",
dest="spacing", default=10.,
help="Tooth Spacing")
self.OptionParser.add_option(
"-a", "--angle",
action="store", type="float",
dest="angle", default=20.,
help="Contact Angle")
def effect(self):
length = self.unittouu(str(self.options.length) + 'px')
spacing = self.unittouu(str(self.options.spacing) + 'px')
angle = radians(self.options.angle)
# generate points: list of (x, y) pairs
points = []
x = 0
tas = tan(angle) * spacing
while x < length:
# move along path, generating the next 'tooth'
points.append((x, 0))
points.append((x + tas, spacing))
points.append((x + spacing, spacing))
points.append((x + spacing + tas, 0))
x += spacing * 2.
path = points_to_svgd(points)
# Embed gear in group to make animation easier:
# Translate group, Rotate path.
view_center = computePointInNode(list(self.view_center), self.current_layer)
t = 'translate(' + str(view_center[0]) + ',' + \
str(view_center[1]) + ')'
g_attribs = {
inkex.addNS('label', 'inkscape'): 'RackGear' + str(length),
'transform': t}
g = inkex.etree.SubElement(self.current_layer, 'g', g_attribs)
# Create SVG Path for gear
style = {'stroke': '#000000', 'fill': 'none', 'stroke-width': str(self.unittouu('1px'))}
gear_attribs = {
'style': simplestyle.formatStyle(style),
'd': path}
gear = inkex.etree.SubElement(
g, inkex.addNS('path', 'svg'), gear_attribs)
if __name__ == '__main__':
e = RackGear()
e.affect()