baffle_maker.py

#! /usr/bin/env python
'''
Generates Inkscape SVG file containing box components needed to 
laser cut a tabbed construction box taking kerf and clearance into account

Copyright (C) 2011 elliot white   elliot@twot.eu
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 3 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, see <http://www.gnu.org/licenses/>.
'''
__version__ = "0.8" ### please report bugs, suggestions etc to bugs@twot.eu ###

from ink_helper import *
from math import pi, sin, cos

_ = gettext.gettext

def x_slit(center, orient, angle):
  '''
  make one x_slit starting 
  orient -- vector from center edge of baffle, slit only goes half of orient length
  angle (radians) is angle of the slit (just try it and see?)
  '''
  orient = Vec2(orient) 
  w = orient.norm()
  out = orient / w
  up = Vec2([out[1], -out[0]])
  center = Vec2(center)
  
  path = Path([center + out * w/2. + up * sin(angle) * w/2])
  path.append(center - out * w/2. - up * sin(angle) * w/2)
  path.append(center - out * w/2. + up * sin(angle) * w/2)
  path.append(center + out * w/2. - up * sin(angle) * w/2)
  path.append(center + out * w/2. + up * sin(angle) * w/2)
  return path

def u_slit(center, orient, angle):
  '''
  make one a single of u_slits
  '''
  orient = Vec2(orient) 
  w = orient.norm()
  out = orient / w
  up = Vec2([out[1], -out[0]])
  center = Vec2(center)
  
  path1 = Path([center + out * w + up * sin(angle) * w])
  path1.append(center + out * w / 2. + up * sin(angle) * w/2)
  path1.append(center + out * w / 2. - up * sin(angle) * w/2)
  path1.append(center + out * w - up * sin(angle) * w)

  return path1

def baffle(start, width, dy, angle, n):
  '''
  Make N slits at a dy spaceing starting at start.
  angle is the slit angle
  '''
  orient = Vec2(width, 0)
  start = Vec2(start)
  up = Vec2(0, 1.)
  x_slits = []
  u_slits = []
  center = start + orient + up * dy/2
  for i in range(n):
    x_slits.append(x_slit(center + i * dy * up, orient, angle))

  x_fold = []
  u_fold = []
  dash = Path([start + orient])
  ddy = dy / 10.
  dash.append_from_last(up * ddy)
  n_dash = int(n * dy  / ddy)
  for s in range(0, n_dash, 3):
    x_fold.append(dash.translate(up * s * ddy))
    u_fold.append(dash.translate(up * s * ddy + orient * 2.1))

  x_outline = Path()
  x_outline.append(start)
  x_outline.append_from_last(2 * orient)
  x_outline.append_from_last((n + 0) * up * dy)
  x_outline.append_from_last(-2 * orient)
  x_outline.append_from_last(-(n + 0) * up * dy)
  
  u_outline = Path()
  u_outline.append(start + orient * 2.1)
  u_outline.append_from_last(2 * orient)
  for i in range(n):
    u_outline.extend(u_slit(center + i * dy * up + orient * 2.1,  orient, angle))
  u_outline.append(start + 4.1 * orient + n * up * dy)
  u_outline.append_from_last(-2 * orient)
  for i in range(n - 1, -1, -1):
    u_outline.extend(u_slit(center + i * dy * up + orient * 2.1,  -orient, angle))
  u_outline.append(start + orient * 2.1)

  
  ## make a list of parts.
  out = [x_slits, x_fold, [x_outline], u_fold, [u_outline]]
  out = [''.join([p.drawXY() for p in path]) for path in out]
  return out
  
class TSlotBoxMaker(inkex.Effect):
  def __init__(self):
      # Call the base class constructor.
      inkex.Effect.__init__(self)
      # Define options
      self.OptionParser.add_option('--unit',action='store',type='string',
        dest='unit',default='mm',help='Measure Units')
      self.OptionParser.add_option('--height',action='store',type='float',
        dest='height',default=100,help='Height of baffle')
      self.OptionParser.add_option('--angle',action='store',type='float',
        dest='angle',default=100,help='Angle of baffle')
      self.OptionParser.add_option('--dy',action='store',type='float',
        dest='dy',default=100,help='distance between baffles')
      self.OptionParser.add_option('--N',action='store',type='float',
        dest='N',default=100,help='number of slits')
      
  def effect(self):
    # Get access to main SVG document element and get its dimensions.
    svg = self.document.getroot()
    
    # Get the attibutes:
    widthDoc  = self.unittouu(svg.get('width'))
    heightDoc = self.unittouu(svg.get('height'))

    # Create a new layer.
    layer = inkex.etree.SubElement(svg, 'g')
    layer.set(inkex.addNS('label', 'inkscape'), 'newlayer')
    layer.set(inkex.addNS('groupmode', 'inkscape'), 'layer')
    
    parent=self.current_layer
    
    # Get script's option values.
    unit=self.options.unit
    H = self.unittouu( str(self.options.height)  + unit )
    angle = float(self.options.angle) * pi / 180
    N = int(self.options.N)
    dy = self.unittouu(str(self.options.dy)  + unit )
    width = H / cos(angle)
    [drawS(obj, parent) for obj in baffle([0, 0], width, dy, angle, N)]


# Create effect instance and apply it.
effect = TSlotBoxMaker()
effect.affect()