import math, inkex, simplestyle, simplepath, bezmisc

class Motion(inkex.Effect):

def __init__(self):

inkex.Effect.__init__(self)

self.OptionParser.add_option("-a", "--angle",

action="store", type="float",

dest="angle", default=45.0,

help="direction of the motion vector")

self.OptionParser.add_option("-m", "--magnitude",

action="store", type="float",

dest="magnitude", default=100.0,

help="magnitude of the motion vector")

def makeface(self,last,(cmd, params)):

a = []

a.append(['M',last[:]])

a.append([cmd, params[:]])

#translate path segment along vector

np = params[:]

defs = simplepath.pathdefs[cmd]

for i in range(defs[1]):

if defs[3][i] == 'x':

np[i] += self.vx

elif defs[3][i] == 'y':

np[i] += self.vy

a.append(['L',[np[-2],np[-1]]])

#reverse direction of path segment

np[-2:] = last[0]+self.vx,last[1]+self.vy

if cmd == 'C':

c1 = np[:2], np[2:4] = np[2:4], np[:2]

a.append([cmd,np[:]])

a.append(['Z',[]])

face = inkex.etree.SubElement(self.facegroup,inkex.addNS('path','svg'),{'d':simplepath.formatPath(a)})

def effect(self):

self.vx = math.cos(math.radians(self.options.angle))*self.options.magnitude

self.vy = math.sin(math.radians(self.options.angle))*self.options.magnitude

for id, node in self.selected.iteritems():

if node.tag == inkex.addNS('path','svg'):

group = inkex.etree.SubElement(node.getparent(),inkex.addNS('g','svg'))

self.facegroup = inkex.etree.SubElement(group, inkex.addNS('g','svg'))

group.append(node)

t = node.get('transform')

if t:

group.set('transform', t)

node.set('transform','')

s = node.get('style')

self.facegroup.set('style', s)

p = simplepath.parsePath(node.get('d'))

for cmd,params in p:

tees = []

if cmd == 'C':

bez = (last,params[:2],params[2:4],params[-2:])

tees = [t for t in bezmisc.beziertatslope(bez,(self.vy,self.vx)) if 0<t<1]

tees.sort()

segments = []

if len(tees) == 0 and cmd in ['L','C']:

segments.append([cmd,params[:]])

elif len(tees) == 1:

one,two = bezmisc.beziersplitatt(bez,tees[0])

segments.append([cmd,list(one[1]+one[2]+one[3])])

segments.append([cmd,list(two[1]+two[2]+two[3])])

elif len(tees) == 2:

one,two = bezmisc.beziersplitatt(bez,tees[0])

two,three = bezmisc.beziersplitatt(two,tees[1])

segments.append([cmd,list(one[1]+one[2]+one[3])])

segments.append([cmd,list(two[1]+two[2]+two[3])])

segments.append([cmd,list(three[1]+three[2]+three[3])])

for seg in segments:

self.makeface(last,seg)

last = seg[1][-2:]

if cmd == 'M':

subPathStart = params[-2:]

if cmd == 'Z':

last = subPathStart

else:

last = params[-2:]

if __name__ == '__main__':

e = Motion()

e.affect()