Source code for boxes.gears

#! /usr/bin/env python
# -*- coding: utf-8 -*-
""

'''
Copyright (C) 2007 Aaron Spike  (aaron @ ekips.org)
Copyright (C) 2007 Tavmjong Bah (tavmjong @ free.fr)
Copyright (C) http://cnc-club.ru/forum/viewtopic.php?f=33&t=434&p=2594#p2500
Copyright (C) 2014 J├╝rgen Weigert (juewei@fabmail.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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

2014-03-20 jw@suse.de 0.2  Option --accuracy=0 for automatic added.
2014-03-21                 sent upstream: https://bugs.launchpad.net/inkscape/+bug/1295641
2014-03-21 jw@suse.de 0.3  Fixed center of rotation for gears with odd number of teeth.
2014-04-04 juewei     0.7  Revamped calc_unit_factor(). 
2014-04-05 juewei    0.7a  Correctly positioned rack gear.
                       The geometry above the meshing line is wrong.
2014-04-06 juewei    0.7b  Undercut detection added. Reference:
               http://nptel.ac.in/courses/IIT-MADRAS/Machine_Design_II/pdf/2_2.pdf
               Manually merged https://github.com/jnweiger/inkscape-gears-dev/pull/15
2014-04-07 juewei    0.7c  Manually merged https://github.com/jnweiger/inkscape-gears-dev/pull/17
2014-04-09 juewei    0.8   Fixed https://github.com/jnweiger/inkscape-gears-dev/issues/19
			   Ring gears are ready for production now. Thanks neon22 for driving this.
			   Profile shift implemented (Advanced Tab), fixing 
			   https://github.com/jnweiger/inkscape-gears-dev/issues/9
2015-05-29 juewei 0.9 	ported to inkscape 0.91
			AttributeError: 'module' object inkex has no attribute 'uutounit
			Fixed https://github.com/jnweiger/inkscape-gears-dev
'''

from os import devnull # for debugging
from math import pi, cos, sin, tan, radians, degrees, ceil, asin, acos, sqrt
two_pi = 2 * pi
import argparse
from boxes.vectors import kerf, vdiff, vlength

__version__ = '0.9'

[docs]def linspace(a,b,n): """ return list of linear interp of a to b in n steps - if a and b are ints - you'll get an int result. - n must be an integer """ return [a+x*(b-a)/(n-1) for x in range(0,n)]
[docs]def involute_intersect_angle(Rb, R): " " Rb, R = float(Rb), float(R) return (sqrt(R**2 - Rb**2) / (Rb)) - (acos(Rb / R))
[docs]def point_on_circle(radius, angle): " return xy coord of the point at distance radius from origin at angle " x = radius * cos(angle) y = radius * sin(angle) return (x, y)
### Undercut support functions
[docs]def undercut_min_teeth(pitch_angle, k=1.0): """ computes the minimum tooth count for a spur gear so that no undercut with the given pitch_angle (in deg) and an addendum = k * metric_module, where 0 < k < 1 Note: The return value should be rounded upwards for perfect safety. E.g. min_teeth = int(math.ceil(undercut_min_teeth(20.0))) # 18, not 17 """ x = max(sin(radians(pitch_angle)), 0.01) return 2*k /(x*x)
[docs]def undercut_max_k(teeth, pitch_angle=20.0): """ computes the maximum k value for a given teeth count and pitch_angle so that no undercut occurs. """ x = max(sin(radians(pitch_angle)), 0.01) return 0.5 * teeth * x * x
[docs]def undercut_min_angle(teeth, k=1.0): """ computes the minimum pitch angle, to that the given teeth count (and profile shift) cause no undercut. """ return degrees(asin(min(0.856, sqrt(2.0*k/teeth)))) # max 59.9 deg
[docs]def have_undercut(teeth, pitch_angle=20.0, k=1.0): """ returns true if the specified number of teeth would cause an undercut. """ return (teeth < undercut_min_teeth(pitch_angle, k))
## gather all basic gear calculations in one place
[docs]def gear_calculations(num_teeth, circular_pitch, pressure_angle, clearance=0, ring_gear=False, profile_shift=0.): """ Put base calcs for spur/ring gears in one place. - negative profile shifting helps against undercut. """ diametral_pitch = pi / circular_pitch pitch_diameter = num_teeth / diametral_pitch pitch_radius = pitch_diameter / 2.0 addendum = 1 / diametral_pitch dedendum = addendum dedendum *= 1+profile_shift addendum *= 1-profile_shift if ring_gear: addendum = addendum + clearance # our method else: dedendum = dedendum + clearance # our method base_radius = pitch_diameter * cos(radians(pressure_angle)) / 2.0 outer_radius = pitch_radius + addendum root_radius = pitch_radius - dedendum # Tooth thickness: Tooth width along pitch circle. tooth_thickness = ( pi * pitch_diameter ) / ( 2.0 * num_teeth ) return (pitch_radius, base_radius, addendum, dedendum, outer_radius, root_radius, tooth_thickness )
[docs]def generate_rack_points(tooth_count, pitch, addendum, pressure_angle, base_height, tab_length, clearance=0, draw_guides=False): """ Return path (suitable for svg) of the Rack gear. - rack gear uses straight sides - involute on a circle of infinite radius is a simple linear ramp - the meshing circle touches at y = 0, - the highest elevation of the teeth is at y = +addendum - the lowest elevation of the teeth is at y = -addendum-clearance - the base_height extends downwards from the lowest elevation. - we generate this middle tooth exactly centered on the y=0 line. (one extra tooth on the right hand side, if number of teeth is even) """ spacing = 0.5 * pitch # rolling one pitch distance on the spur gear pitch_diameter. # roughly center rack in drawing, exact position is so that it meshes # nicely with the spur gear. # -0.5*spacing has a gap in the center. # +0.5*spacing has a tooth in the center. if tab_length <= 0.0: tab_length = 1E-8 tas = tan(radians(pressure_angle)) * addendum tasc = tan(radians(pressure_angle)) * (addendum+clearance) base_top = addendum+clearance base_bot = addendum+clearance+base_height x_lhs = -pitch * 0.5*tooth_count - tab_length # Start with base tab on LHS points = [] # make list of points points.append((x_lhs, base_bot)) points.append((x_lhs, base_top)) x = x_lhs + tab_length+tasc # An involute on a circle of infinite radius is a simple linear ramp. # We need to add curve at bottom and use clearance. for i in range(tooth_count): # move along path, generating the next 'tooth' # pitch line is at y=0. the left edge hits the pitch line at x points.append((x-tasc, base_top)) points.append((x+tas, -addendum)) points.append((x+spacing-tas, -addendum)) points.append((x+spacing+tasc, base_top)) x += pitch # add base on RHS x_rhs = x - tasc + tab_length points.append((x_rhs, base_top)) points.append((x_rhs, base_bot)) # We don't close the path here. Caller does it. # points.append((x_lhs, base_bot)) # Draw line representing the pitch circle of infinite diameter guide_path = None p = [] if draw_guides: p.append( (x_lhs + 0.5 * tab_length, 0) ) p.append( (x_rhs - 0.5 * tab_length, 0) ) return (points, p)
[docs]def generate_spur_points(teeth, base_radius, pitch_radius, outer_radius, root_radius, accuracy_involute, accuracy_circular): """ given a set of core gear params - generate the svg path for the gear """ half_thick_angle = two_pi / (4.0 * teeth ) #?? = pi / (2.0 * teeth) pitch_to_base_angle = involute_intersect_angle( base_radius, pitch_radius ) pitch_to_outer_angle = involute_intersect_angle( base_radius, outer_radius ) - pitch_to_base_angle start_involute_radius = max(base_radius, root_radius) radii = linspace(start_involute_radius, outer_radius, accuracy_involute) angles = [involute_intersect_angle(base_radius, r) for r in radii] centers = [(x * two_pi / float( teeth) ) for x in range( teeth ) ] points = [] for c in centers: # Angles pitch1 = c - half_thick_angle base1 = pitch1 - pitch_to_base_angle offsetangles1 = [ base1 + x for x in angles] points1 = [ point_on_circle( radii[i], offsetangles1[i]) for i in range(0,len(radii)) ] pitch2 = c + half_thick_angle base2 = pitch2 + pitch_to_base_angle offsetangles2 = [ base2 - x for x in angles] points2 = [ point_on_circle( radii[i], offsetangles2[i]) for i in range(0,len(radii)) ] points_on_outer_radius = [ point_on_circle(outer_radius, x) for x in linspace(offsetangles1[-1], offsetangles2[-1], accuracy_circular) ] if root_radius > base_radius: pitch_to_root_angle = pitch_to_base_angle - involute_intersect_angle(base_radius, root_radius ) root1 = pitch1 - pitch_to_root_angle root2 = pitch2 + pitch_to_root_angle points_on_root = [point_on_circle (root_radius, x) for x in linspace(root2, root1+(two_pi/float(teeth)), accuracy_circular) ] p_tmp = points1 + points_on_outer_radius[1:-1] + points2[::-1] + points_on_root[1:-1] # [::-1] reverses list; [1:-1] removes first and last element else: points_on_root = [point_on_circle (root_radius, x) for x in linspace(base2, base1+(two_pi/float(teeth)), accuracy_circular) ] p_tmp = points1 + points_on_outer_radius[1:-1] + points2[::-1] + points_on_root # [::-1] reverses list points.extend( p_tmp ) return (points)
[docs]def inkbool(val): return val not in ("False", False, "0", 0, "None", None)
[docs]class OptionParser(argparse.ArgumentParser): types = { "int" : int, "float" : float, "string" : str, "inkbool" : inkbool, }
[docs] def add_option(self, short, long_, **kw): kw["type"] = self.types[kw["type"]] names = [] if short: names.append("-" + short.replace("-", "_")[1:]) if long_: names.append("--" + long_.replace("-", "_")[2:]) self.add_argument(*names, **kw)
[docs]class Gears(): def __init__(self, boxes, **kw): # an alternate way to get debug info: # could use inkex.debug(string) instead... try: self.tty = open("/dev/tty", 'w') except: self.tty = open(devnull, 'w') # '/dev/null' for POSIX, 'nul' for Windows. # print >>self.tty, "gears-dev " + __version__ self.boxes = boxes self.OptionParser = OptionParser() self.OptionParser.add_option("-t", "--teeth", action="store", type="int", dest="teeth", default=24, help="Number of teeth") self.OptionParser.add_option("-s", "--system", action="store", type="string", dest="system", default='MM', help="Select system: 'CP' (Cyclic Pitch (default)), 'DP' (Diametral Pitch), 'MM' (Metric Module)") self.OptionParser.add_option("-d", "--dimension", action="store", type="float", dest="dimension", default=1.0, help="Tooth size, depending on system (which defaults to CP)") self.OptionParser.add_option("-a", "--angle", action="store", type="float", dest="angle", default=20.0, help="Pressure Angle (common values: 14.5, 20, 25 degrees)") self.OptionParser.add_option("-p", "--profile-shift", action="store", type="float", dest="profile_shift", default=20.0, help="Profile shift [in percent of the module]. Negative values help against undercut") self.OptionParser.add_option("-u", "--units", action="store", type="string", dest="units", default='mm', help="Units this dialog is using") self.OptionParser.add_option("-A", "--accuracy", action="store", type="int", dest="accuracy", default=0, help="Accuracy of involute: automatic: 5..20 (default), best: 20(default), medium 10, low: 5; good acuracy is important with a low tooth count") # Clearance: Radial distance between top of tooth on one gear to bottom of gap on another. self.OptionParser.add_option("", "--clearance", action="store", type="float", dest="clearance", default=0.0, help="Clearance between bottom of gap of this gear and top of tooth of another") self.OptionParser.add_option("", "--annotation", action="store", type="inkbool", dest="annotation", default=False, help="Draw annotation text") self.OptionParser.add_option("-i", "--internal-ring", action="store", type="inkbool", dest="internal_ring", default=False, help="Ring (or Internal) gear style (default: normal spur gear)") self.OptionParser.add_option("", "--mount-hole", action="store", type="float", dest="mount_hole", default=0., help="Mount hole diameter") self.OptionParser.add_option("", "--mount-diameter", action="store", type="float", dest="mount_diameter", default=15, help="Mount support diameter") self.OptionParser.add_option("", "--spoke-count", action="store", type="int", dest="spoke_count", default=3, help="Spokes count") self.OptionParser.add_option("", "--spoke-width", action="store", type="float", dest="spoke_width", default=5, help="Spoke width") self.OptionParser.add_option("", "--holes-rounding", action="store", type="float", dest="holes_rounding", default=5, help="Holes rounding") self.OptionParser.add_option("", "--active-tab", action="store", type="string", dest="active_tab", default='', help="Active tab. Not used now.") self.OptionParser.add_option("-x", "--centercross", action="store", type="inkbool", dest="centercross", default=False, help="Draw cross in center") self.OptionParser.add_option("-c", "--pitchcircle", action="store", type="inkbool", dest="pitchcircle", default=False, help="Draw pitch circle (for mating)") self.OptionParser.add_option("-r", "--draw-rack", action="store", type="inkbool", dest="drawrack", default=False, help="Draw rack gear instead of spur gear") self.OptionParser.add_option("", "--rack-teeth-length", action="store", type="int", dest="teeth_length", default=12, help="Length (in teeth) of rack") self.OptionParser.add_option("", "--rack-base-height", action="store", type="float", dest="base_height", default=8, help="Height of base of rack") self.OptionParser.add_option("", "--rack-base-tab", action="store", type="float", dest="base_tab", default=14, help="Length of tabs on ends of rack") self.OptionParser.add_option("", "--undercut-alert", action="store", type="inkbool", dest="undercut_alert", default=False, help="Let the user confirm a warning dialog if undercut occurs. This dialog also shows helpful hints against undercut")
[docs] def drawPoints(self, lines, kerfdir=1, close=True): if not lines: return if kerfdir != 0: lines = kerf(lines, self.boxes.burn*kerfdir, closed=close) self.boxes.ctx.save() self.boxes.ctx.move_to(*lines[0]) for x, y in lines[1:]: self.boxes.ctx.line_to(x, y) if close: self.boxes.ctx.line_to(*lines[0]) self.boxes.ctx.restore()
[docs] def calc_circular_pitch(self): """ We use math based on circular pitch. """ dimension = self.options.dimension if self.options.system == 'CP': # circular pitch circular_pitch = dimension * 25.4 elif self.options.system == 'DP': # diametral pitch circular_pitch = pi * 25.4 / dimension elif self.options.system == 'MM': # module (metric) circular_pitch = dimension else: raise ValueError("unknown system '%s', try CP, DP, MM" % self.options.system) # circular_pitch defines the size in mm return circular_pitch
[docs] def generate_spokes(self, root_radius, spoke_width, spokes, mount_radius, mount_hole, unit_factor, unit_label): """ given a set of constraints - generate the svg path for the gear spokes - lies between mount_radius (inner hole) and root_radius (bottom of the teeth) - spoke width also defines the spacing at the root_radius - mount_radius is adjusted so that spokes fit if there is room - if no room (collision) then spokes not drawn """ if not spokes: return [] # Spokes collision = False # assume we draw spokes messages = [] # messages to send back about changes. spoke_holes = [] r_outer = root_radius - spoke_width try: spoke_count = spokes spokes = [i*2*pi/spokes for i in range(spoke_count)] except TypeError: spoke_count = len(spokes) spokes = [radians(a) for a in spokes] spokes.append(spokes[0]+two_pi) # checks for collision with spokes # check for mount hole collision with inner spokes if mount_radius <= mount_hole/2: adj_factor = (r_outer - mount_hole/2) / 5 if adj_factor < 0.1: # not enough reasonable room collision = True else: mount_radius = mount_hole/2 + adj_factor # small fix messages.append("Mount support too small. Auto increased to %2.2f%s." % (mount_radius/unit_factor*2, unit_label)) # then check to see if cross-over on spoke width for i in range(spoke_count): angle = spokes[i]-spokes[i-1] if spoke_width >= angle * mount_radius: adj_factor = 1.2 # wrong value. its probably one of the points distances calculated below mount_radius += adj_factor messages.append("Too many spokes. Increased Mount support by %2.3f%s" % (adj_factor/unit_factor, unit_label)) # check for collision with outer rim if r_outer <= mount_radius: # not enough room to draw spokes so cancel collision = True if collision: # don't draw spokes if no room. messages.append("Not enough room for Spokes. Decrease Spoke width.") else: # draw spokes for i in range(spoke_count): self.boxes.ctx.save() start_a, end_a = spokes[i], spokes[i+1] # inner circle around mount asin_factor = spoke_width/mount_radius/2 # check if need to clamp radius asin_factor = max(-1.0, min(1.0, asin_factor)) # no longer needed - resized above a = asin(asin_factor) # is inner circle too small asin_factor = spoke_width/r_outer/2 # check if need to clamp radius asin_factor = max(-1.0, min(1.0, asin_factor)) # no longer needed - resized above a2 = asin(asin_factor) l = vlength(vdiff(point_on_circle(mount_radius, start_a + a), point_on_circle(r_outer, start_a + a2))) self.boxes.moveTo(*point_on_circle(mount_radius, start_a + a), degrees=degrees(start_a)) self.boxes.polyline( l, +90+degrees(a2), 0, (degrees(end_a-start_a-2*a2), r_outer), 0, +90+degrees(a2), l, 90-degrees(a), 0, (-degrees(end_a-start_a-2*a), mount_radius), 0, 90+degrees(a2), 0 ) self.boxes.ctx.restore() return messages
[docs] def sizes(self, **kw): self.options = self.OptionParser.parse_args(["--%s=%s" % (name,value) for name, value in kw.items()]) # Pitch (circular pitch): Length of the arc from one tooth to the next) # Pitch diameter: Diameter of pitch circle. pitch = self.calc_circular_pitch() if self.options.drawrack: base_height = self.options.base_height * unit_factor tab_width = self.options.base_tab * unit_factor tooth_count = self.options.teeth_length width = tooth_count * pitch + 2*tab_width height = base_height+ 2* addendum return 0, width, height teeth = self.options.teeth # Angle of tangent to tooth at circular pitch wrt radial line. angle = self.options.angle # Clearance: Radial distance between top of tooth on one gear to # bottom of gap on another. clearance = self.options.clearance # * unit_factor # Replace section below with this call to get the combined gear_calculations() above (pitch_radius, base_radius, addendum, dedendum, outer_radius, root_radius, tooth) = gear_calculations(teeth, pitch, angle, clearance, self.options.internal_ring, self.options.profile_shift*0.01) if self.options.internal_ring: outer_radius += self.options.spoke_width return pitch_radius, 2*outer_radius, 2*outer_radius
[docs] def gearCarrier(self, r, spoke_width, positions, mount_radius, mount_hole, circle=True, callback=None, move=None): width = 2*r+spoke_width if self.boxes.move(width, width, move, before=True): return try: positions = [i*360/positions for i in range(positions)] except TypeError: pass self.boxes.ctx.save() self.boxes.moveTo(width/2.0, width/2.0) if callback: self.boxes.cc(callback, None) self.generate_spokes(r+0.5*spoke_width, spoke_width, positions, mount_radius, mount_hole, 1, "") self.boxes.hole(0, 0, mount_hole) for angle in positions: self.boxes.ctx.save() self.boxes.moveTo(0, 0, angle) self.boxes.hole(r, 0, mount_hole) self.boxes.ctx.restore() self.boxes.moveTo(r+0.5*spoke_width+self.boxes.burn, 0, 90) self.boxes.corner(360, r+0.5*spoke_width) self.boxes.ctx.restore() self.boxes.move(width, width, move)
def __call__(self, teeth_only=False, move="", callback=None, **kw): """ Calculate Gear factors from inputs. - Make list of radii, angles, and centers for each tooth and iterate through them - Turn on other visual features e.g. cross, rack, annotations, etc """ self.options = self.OptionParser.parse_args(["--%s=%s" % (name,value) for name, value in kw.items()]) warnings = [] # list of extra messages to be shown in annotations # calculate unit factor for units defined in dialog. unit_factor = 1 # User defined options teeth = self.options.teeth # Angle of tangent to tooth at circular pitch wrt radial line. angle = self.options.angle # Clearance: Radial distance between top of tooth on one gear to # bottom of gap on another. clearance = self.options.clearance * unit_factor mount_hole = self.options.mount_hole * unit_factor # for spokes mount_radius = self.options.mount_diameter * 0.5 * unit_factor spoke_count = self.options.spoke_count spoke_width = self.options.spoke_width * unit_factor holes_rounding = self.options.holes_rounding * unit_factor # unused # visible guide lines centercross = self.options.centercross # draw center or not (boolean) pitchcircle = self.options.pitchcircle # draw pitch circle or not (boolean) # Accuracy of teeth curves accuracy_involute = 20 # Number of points of the involute curve accuracy_circular = 9 # Number of points on circular parts if self.options.accuracy is not None: if self.options.accuracy == 0: # automatic if teeth < 10: accuracy_involute = 20 elif teeth < 30: accuracy_involute = 12 else: accuracy_involute = 6 else: accuracy_involute = self.options.accuracy accuracy_circular = max(3, int(accuracy_involute/2) - 1) # never less than three # print >>self.tty, "accuracy_circular=%s accuracy_involute=%s" % (accuracy_circular, accuracy_involute) # Pitch (circular pitch): Length of the arc from one tooth to the next) # Pitch diameter: Diameter of pitch circle. pitch = self.calc_circular_pitch() # Replace section below with this call to get the combined gear_calculations() above (pitch_radius, base_radius, addendum, dedendum, outer_radius, root_radius, tooth) = gear_calculations(teeth, pitch, angle, clearance, self.options.internal_ring, self.options.profile_shift*0.01) b = self.boxes.burn # Add Rack (instead) if self.options.drawrack: base_height = self.options.base_height * unit_factor tab_width = self.options.base_tab * unit_factor tooth_count = self.options.teeth_length (points, guide_points) = generate_rack_points(tooth_count, pitch, addendum, angle, base_height, tab_width, clearance, pitchcircle) width = tooth_count * pitch + 2 * tab_width height = base_height + 2 * addendum if self.boxes.move(width, height, move, before=True): return self.boxes.cc(callback, None) self.boxes.moveTo(width/2.0, base_height+addendum, -180) if base_height < 0: points = points[1:-1] self.drawPoints(points, close=base_height >= 0) self.drawPoints(guide_points, kerfdir=0) self.boxes.move(width, height, move) return # Move only width = height = 2 * outer_radius if self.options.internal_ring: width = height = width + 2 * self.options.spoke_width if not teeth_only and self.boxes.move(width, height, move, before=True): return # Detect Undercut of teeth ## undercut = int(ceil(undercut_min_teeth( angle ))) ## needs_undercut = teeth < undercut #? no longer needed ? if have_undercut(teeth, angle, 1.0): min_teeth = int(ceil(undercut_min_teeth(angle, 1.0))) min_angle = undercut_min_angle(teeth, 1.0) + .1 max_k = undercut_max_k(teeth, angle) msg = "Undercut Warning: This gear (%d teeth) will not work well.\nTry tooth count of %d or more,\nor a pressure angle of %.1f [deg] or more,\nor try a profile shift of %d %%.\nOr other decent combinations." % (teeth, min_teeth, min_angle, int(100.*max_k)-100.) # alas annotation cannot handle the degree symbol. Also it ignore newlines. # so split and make a list warnings.extend(msg.split("\n")) # All base calcs done. Start building gear points = generate_spur_points(teeth, base_radius, pitch_radius, outer_radius, root_radius, accuracy_involute, accuracy_circular) if not teeth_only: self.boxes.moveTo(width/2, height/2) self.boxes.cc(callback, None, 0, 0) self.drawPoints(points) # Spokes if not teeth_only and not self.options.internal_ring: # only draw internals if spur gear msg = self.generate_spokes(root_radius, spoke_width, spoke_count, mount_radius, mount_hole, unit_factor, self.options.units) warnings.extend(msg) # Draw mount hole # A : rx,ry x-axis-rotation, large-arch-flag, sweepflag x,y r = mount_hole / 2 self.boxes.hole(0, 0, r) elif not teeth_only: # its a ring gear # which only has an outer ring where width = spoke width r = outer_radius + spoke_width + self.boxes.burn self.boxes.ctx.save() self.boxes.moveTo(r, 0) self.boxes.ctx.arc(-r, 0, r, 0, 2*pi) self.boxes.ctx.restore() # Add center if centercross: cs = pitch / 3.0 # centercross length self.boxes.ctx.save() self.boxes.ctx.move_to(-cs, 0) self.boxes.ctx.line_to(+cs, 0) self.boxes.ctx.move_to(0, -cs) self.boxes.ctx.line_to(0, +cs) self.boxes.ctx.restore() # Add pitch circle (for mating) if pitchcircle: self.boxes.hole(0, 0, pitch_radius) # Add Annotations (above) if self.options.annotation: outer_dia = outer_radius * 2 if self.options.internal_ring: outer_dia += 2 * spoke_width notes = [] notes.extend(warnings) #notes.append('Document (%s) scale conversion = %2.4f' % (self.document.getroot().find(inkex.addNS('namedview', 'sodipodi')).get(inkex.addNS('document-units', 'inkscape')), unit_factor)) notes.extend(['Teeth: %d CP: %2.4f(%s) ' % (teeth, pitch / unit_factor, self.options.units), 'DP: %2.3f Module: %2.4f(mm)' % (25.4 * pi / pitch, pitch), 'Pressure Angle: %2.2f degrees' % (angle), 'Pitch diameter: %2.3f %s' % (pitch_radius * 2 / unit_factor, self.options.units), 'Outer diameter: %2.3f %s' % (outer_dia / unit_factor, self.options.units), 'Base diameter: %2.3f %s' % (base_radius * 2 / unit_factor, self.options.units)#, #'Addendum: %2.4f %s' % (addendum / unit_factor, self.options.units), #'Dedendum: %2.4f %s' % (dedendum / unit_factor, self.options.units) ]) # text height relative to gear size. # ranges from 10 to 22 over outer radius size 60 to 360 text_height = max(10, min(10+(outer_dia-60)/24, 22)) # position above y = - outer_radius - (len(notes)+1) * text_height * 1.2 for note in notes: self.boxes.text(note, -outer_radius, y) y += text_height * 1.2 if not teeth_only: self.boxes.move(width, height, move)
if __name__ == '__main__': e = Gears() e.affect() # Notes