plot bezier curve from SVG

bezier.py

import os
import Image, ImageDraw

def bezier1(p0, p1, t):
    x = p0[0] + t * (p1[0] - p0[0])
    y = p0[1] + t * (p1[1] - p0[1])
    return (x,y)

def bezierN(pts, t):
    res = list(pts)
    for n in range(len(pts), 1, -1):
        for i in range(0,n-1):
            res[i] = bezier1(res[i], res[i+1], t)
    return res[0]

im = Image.new("RGB", (100,100), "white")
draw = ImageDraw.Draw(im)

red = (255,0,0)
green = (0,255,0)
blue = (0,0,255)

pts = [(10,90),(5,40),(60,40),(90,90)]
for pt in pts:
    im.putpixel(pt, red)
draw.line(pts,fill=red)

bezier = []
for t in range(0,10):
    xy = bezierN(pts, t*0.1)
    bezier.append(xy)
    im.putpixel((int(round(xy[0])), int(round(xy[1]))), green)

draw.line(bezier, fill=blue)
#im.save(os.path.expanduser("~/public_html/bezier.png"))
im.show()

cc.path

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footprint.svg

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!-- Created with Inkscape (http://www.inkscape.org/) -->

<svg
   xmlns:svg="http://www.w3.org/2000/svg"
   xmlns="http://www.w3.org/2000/svg"
   version="1.1"
   width="525"
   height="525"
   id="svg2894">
  <defs
     id="defs2898" />
  <path
     d="M 258.02822,449.92907 C 216.23561,444.16139 175.4234,427.25125 143.5,402.47542 133.44605,394.67252 115.73782,376.40039 109.18036,367.06291 94.835361,346.63637 87,321.34904 87,295.47948 87,232.75299 133.79919,178.8344 211.49716,152.043 c 12.57887,-4.33737 22.38442,-6.44909 54.00284,-11.62999 21.98019,-3.60161 22.02147,-3.60438 45.84382,-3.07652 22.28554,0.49381 23.74755,0.41839 22.37059,-1.15407 -4.73363,-5.40575 -5.94414,-12.7887 -3.0848,-18.81431 7.34694,-15.48252 38.4631,-19.396203 53.29234,-6.70293 11.63658,9.96048 8.84962,23.71074 -6.4033,31.59256 l -2.98135,1.54058 4.48135,1.13653 c 29.97155,7.6012 51.58857,15.78955 62.74173,23.76607 43.9615,31.44035 65.76184,69.17043 76.31237,132.07458 2.59087,15.44724 3.06152,20.66622 2.76579,30.66969 -0.32759,11.08174 -0.61314,12.59838 -3.53742,18.78881 -12.54914,26.56529 -45.29719,58.10305 -77.01214,74.16596 -9.30679,4.71368 -36.50951,15.59929 -40.66867,16.27423 -4.47109,0.72556 -5.52752,0.0301 -13.20131,-8.68994 -16.98624,-19.30225 -37.26172,-26.84624 -56.5324,-21.03426 -15.54003,4.68683 -26.35266,13.1073 -38.00509,29.59693 L 283.78817,452 l -6.14408,-0.10587 c -3.37925,-0.0582 -12.20639,-0.9425 -19.61587,-1.96506 z M 53.370467,205.66727 C 28.249651,197.29509 9.6491005,173.14627 4.8739644,142.70497 3.2875779,132.59182 4.3814573,113.41291 7.0815232,104 13.400552,81.970748 26.642885,65.164131 44.515165,56.490784 66.407186,45.866672 90.11011,48.494026 109.47263,63.691002 c 10.99999,8.633515 21.28575,25.372047 25.69146,41.808998 2.93139,10.93652 3.17098,33.37846 0.47933,44.89733 -3.70261,15.84522 -12.00927,31.16159 -21.7755,40.15109 C 101.02749,202.36763 89.929278,206.88516 72,207.59079 61.824211,207.99127 59.679043,207.76977 53.370467,205.66727 z M 286.3585,134.90933 c -16.39324,-4.75014 -29.32495,-29.97227 -26.30291,-51.301407 2.47678,-17.480694 12.49975,-27.621562 27.27732,-27.598154 23.44621,0.03714 40.59738,31.74999 32.21918,59.573871 -4.65394,15.45567 -18.57608,23.5613 -33.19359,19.32569 z m -123.4487,-23.2191 c -10.73876,-4.02211 -18.3823,-15.203079 -21.48735,-31.431676 -4.60026,-24.043396 3.1508,-47.582045 18.19894,-55.267068 7.13808,-3.64539 17.09219,-3.541645 23.5341,0.245281 4.81488,2.830469 9.31944,7.818493 12.27299,13.590231 l 1.70251,3.326998 2.68451,-3.490673 c 7.94555,-10.33164 20.80498,-12.551286 30.37613,-5.243174 15.61603,11.923728 17.20366,48.030713 2.74755,62.486821 -9.46114,9.46114 -22.25377,9.28757 -31.08911,-0.421812 C 200.10578,93.568321 198.38429,92 198.02453,92 c -0.35976,0 -1.45137,1.671884 -2.42581,3.715298 -2.78156,5.833012 -7.39457,11.080752 -12.23303,13.916282 -5.37156,3.14794 -14.96879,4.11379 -20.45589,2.05865 z"
     id="path2928"
     style="fill:#000000" />
</svg>

kicad.py

import time

LIBMODULE_HEADER = 'PCBNEW-LibModule-V1  '
LIBMODULE_HEADER += time.strftime("%c", time.localtime())
LIBMODULE_HEADER += '\n# encoding utf-8\n'
LIBMODULE_HEADER += 'Units mm\n'

class LibModule:
    '''Container (file) for all the Modules'''
    def __init__(self, filename):
        self.filename = filename
        self.modules = []

    def add_module(self, mod):
        self.modules.append(mod)

    def write(self):
        f = open(self.filename, 'w')
        f.write(LIBMODULE_HEADER)
        # Index
        f.write("$INDEX\n")
        for m in self.modules:
            f.write(m.name + '\n')
        f.write("$EndINDEX\n")
        for m in self.modules:
            f.write(str(m))
        f.close()


class Module:
    def __init__(self, name):
        self.name = name
        self.position = {
            'Xpos': 0,
            'Ypos': 0,
            'orientation': 0,
            'layer': 15,
            'timestamp': '00000000 00000000',
            'attr1': '~',
            'attr2': '~'}
        self.cd = ''
        self.kw = ''
        self.fields = []
        self.drawings = []
        self.pads = [] # not implemented

        self.reference('M*')
        self.value(name)

    def __str__(self):
        s = '$MODULE ' + self.name + '\n'
        # Position
        s += 'Po {Xpos} {Ypos} {orientation} {layer} {timestamp} {attr1}{attr2}\n'.format(**self.position)
        # Module lib name
        s += 'Li ' + self.name + '\n'
        # Comments & keywords
        s += 'Cd ' + self.cd + '\n'
        s += 'Kw ' + self.kw + '\n'
        # TimeStampOp (?)
        s += 'Sc 00000000\n'
        # AR (?)
        s += 'AR ' + self.name + '\n'
        # Op (?)
        s += 'Op 0 0 0\n'
        # fields
        for f in self.fields:
            s += 'T{nb} {Xpos} {Ypos} {Xsize} {Ysize} {rotation} {penWidth} N {visible} {layer} N "{text}"\n'.format(**f)
        # drawings
        for d in self.drawings:
            s += str(d)
        s += '$EndMODULE ' + self.name + '\n'
        return s

    def position(self, x=None, y=None, orientation=None, layer=None):
        if x is not None:
            self.position['Xpos'] = x
        if y is not None:
            self.position['Ypos'] = y
        if orientation is not None:
            self.position['orientation'] = orientation
        if layer is not None:
            self.position['layer'] = layer

    def comment(self, desc=''):
        self.cd = desc

    def keywords(self, kw=''):
        self.kw = kw

    def field(self, nb, Xpos=0, Ypos=0, Xsize=0.8128, Ysize=0.8128, rotation=0, penWidth=0.1524, visible=True, layer=21, text=''):
        if visible:
            visible = 'V'
        else:
            visible = 'I'

        # Remove posible duplicate
        self.fields = [f for f in self.fields if f.get('nb') != nb]

        f = {
        'nb': nb,
        'Xpos': Xpos,
        'Ypos': Ypos,
        'Xsize': Xsize,
        'Ysize': Ysize,
        'rotation': rotation,
        'penWidth': penWidth,
        'visible': visible,
        'layer': layer,
        'text': text}
        self.fields.append(f)

    def reference(self, ref):
        self.field(0, text=ref)
    def value(self, value):
        self.field(1, text=value)

    def draw(self, d):
        self.drawings.append(d)

class Segment:
    def __init__(self, start, end, width, layer=21):
        self.start = start
        self.end = end
        self.width = width
        self.layer = layer

    def __str__(self):
        s = 'DS '
        s += ' '.join(map(str, self.start)) + ' '
        s += ' '.join(map(str, self.end)) + ' '
        s += str(self.width) + ' '
        s += str(self.layer) + '\n'
        return s

class Polygon:
    def __init__(self, pts, width=0, layer=21):
        self.length = len(pts)
        self.pts = list(pts)
        self.width = width
        self.layer = layer

    def __str__(self):
        s = 'DP 0 0 0 0 '
        s += str(self.length) + ' '
        s += str(self.width) + ' '
        s += str(self.layer) + '\n'
        for pt in self.pts:
            s += 'Dl ' + ' '.join(map(str, pt)) + '\n'
        return s

class Circle:
    def __init__(self, center, radius, width, layer=21):
        self.center = center
        self.pt = (center[0] + radius, center[1])
        self.width = width
        self.layer = layer

    def __str__(self):
        s = 'DC '
        s += ' '.join(map(str, self.center)) + ' '
        s += ' '.join(map(str, self.pt)) + ' '
        s += str(self.width) + ' '
        s += str(self.layer) + '\n'
        return s

kicad.test.py

import kicad
import svg
import sys

f = svg.Svg(sys.argv[1])

l = kicad.LibModule("/tmp/1.mod")
m = kicad.Module("MyTest")
m.reference('G*')
m.value(f.title())

a,b = f.bbox()
# We want a 10.0mm width logo
width = 100.0
ratio = width/(b-a).x
# Centering offset
offset = (a-b)*0.5*ratio

for draw in f.drawing:
    if isinstance(draw, svg.Path):
        for segment in draw.simplify(0.1):
            pts = [x.coord() for x in segment]
            pts.reverse()
            p1 = pts.pop()
            while pts:
                p2 = pts.pop()
                m.draw(kicad.Segment(p1, p2, 0.20))
                p1 = p2
    elif isinstance(draw, svg.Circle):
        m.draw(kicad.Circle(draw.center.coord(), draw.radius, 0.20))
    else:
        print("Unsupported SVG element" + draw)

#for s in f.scale(ratio).translate(offset).simplify(0.01):
#    m.draw(kicad.Polygon([x.coord() for x in s]))

l.add_module(m)
l.write()

sample

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str.py

#!/usr/bin/python2
import sys
import re

if len(sys.argv) < 2:
    print "Usage: %s \"path string\"" % sys.argv[0]
    sys.exit()

path = re.split(r"([+-]?\ *\d+(?:\.\d*)?|\.\d+)", sys.argv[1])
# (?:...)non-capturing version of regular parentheses
# because re.split()  If capturing parentheses are used in pattern, then the text of all groups in the pattern are also returned as part of the resulting list

# Number of expected values per commands
cmd = {'M':2, 'L':2, 'Z':0, 'H':1, 'V':1, 'A':7, 'Q':4, 'T':2, 'C':6, 'S':4}
# 'pair' : (x,y)
# 'coord' : x
# 'length' : L > 0
# 'bool' : 0|1
syntax = {
'M': ['pair'],
'L': ['pair'],
'Z': [],
'H': ['coord'],
'V': ['coord'], 
'A': ['length', 'length', 'length', 'bool', 'bool', 'pair'],
'Q': ['pair', 'pair'],
'T': ['pair'],
'C': ['pair', 'pair', 'pair'],
'S': ['pair', 'pair']
}

# clean-up path in p[]
p = []
for elt in path:
# remove all spaces
    elt = elt.strip()
    elt = elt.replace(' ','')
    if (elt == ''):
        continue;
# remove all commas (not strictly necessary in SVG)
    if (elt == ','):
        continue;
# split commands into single one (e.g.: 'ZM' -> 'Z','M')
# check command validity
    if elt.isalpha():
        for i in list(elt):
            if (i.upper() in cmd.keys()): p.append(i)
            else: print i, " is not a valid command"
# not a command? should be a numeric
    else:
        try: p.append(float(elt))
        except ValueError: print elt, " should be numeric"


# Split series of identical commands into individual blocks
i = 1
elt = p[0]   # current element
c = 'M'      # Current command
while i <= len(p):
# Expect a command, remember it
    if str(elt).upper() in cmd.keys():
        c = elt
        l = [c]
        for j in range(0, cmd[c.upper()]):
             l.append(p[i+j])
        i += cmd[c.upper()]
# Get next element
        try: elt = p[i]
        except: elt = '' # End of list?
        i += 1
        print l
    else:
# We expect a new command but did not get one: use previous one and realign
         elt = c
         i -= 1


# Change lower case command to upper case (relative to absolute)

svg.py

import re
import numbers, math
import xml.etree.ElementTree as etree

class Transformable:
    '''Abstract class for objects that can be geometrically drawn & transformed'''
    def __init__(self, elt=None):
        # a 'Transformable' is represented as a list of Transformable items
        self.items = []
        # Unit transformation matrix on init
        self.matrix = Matrix()
        self.xmin = None
        self.xmax = None
        self.ymin = None
        self.ymax = None
        if elt is not None:
            # Parse transform attibute to update self.matrix
            self.getTransformations(elt)

    def bbox(self):
        '''Bounding box'''
        for x in self.items:
            pmin, pmax = x.bbox()
            if self.xmin == None or pmin.x < self.xmin:
                self.xmin = pmin.x
            if self.ymin == None or pmin.y < self.ymin:
                self.ymin = pmin.y
            if self.xmax == None or pmax.x > self.xmax:
                self.xmax = pmax.x
            if self.ymax == None or pmax.y > self.ymax:
                self.ymax = pmax.y

        return (Point(self.xmin,self.ymin), Point(self.xmax,self.ymax))

    # Parse transform field
    def getTransformations(self, elt):
        t = elt.get('transform')
        if t is None: return

        svg_transforms = [
                'matrix', 'translate', 'scale', 'rotate', 'skewX', 'skewY']

        # match any SVG transformation with its parameter (until final parenthese)
        # [^)]*    == anything but a closing parenthese
        # '|'.join == OR-list of SVG transformations
        transforms = re.findall(
                '|'.join([x + '[^)]*\)' for x in svg_transforms]), t)

        for t in transforms:
            op, arg = t.split('(')
            op = op.strip()
            # Keep only numbers
            arg = [float(x) for x in
                    re.findall(r"([+-]?\ *\d+(?:\.\d*)?|\.\d+)", arg)]
            print('transform: ' + op + ' '+ str(arg))

            if op == 'matrix':
                self.matrix *= Matrix(arg)

            if op == 'translate':
                tx, ty = arg
                self.matrix *= Matrix([1, 0, 0, 1, tx, ty])

            if op == 'scale':
                sx = arg[0]
                if len(arg) == 1: sy = sx
                else: sy = arg[1]
                self.matrix *= Matrix([sx, 0, 0, sy, 0, 0])

            if op == 'rotate':
                cosa = math.cos(math.radians(arg[0]))
                sina = math.sin(math.radians(arg[0]))
                if len(arg) != 1:
                    tx, ty = arg[1:3]
                    self.matrix *= Matrix([1, 0, 0, 1, tx, ty])
                self.matrix *= Matrix([cosa, sina, -sina, cosa, 0, 0])
                if len(arg) != 1:
                    self.matrix *= Matrix([1, 0, 0, 1, -tx, -ty])

            if op == 'skewX':
                tana = math.tan(math.radians(arg[0]))
                self.matrix *= Matrix([1, 0, tana, 1, 0, 0])

            if op == 'skewY':
                tana = math.tan(math.radians(arg[0]))
                self.matrix *= Matrix([1, tana, 0, 1, 0, 0])

    def transform(self, matrix=None):
        for x in self.items:
            x.transform(self.matrix)

    def scale(self, ratio):
        for x in self.items:
            x.scale(ratio)
        return self

    def translate(self, offset):
        for x in self.items:
            x.translate(offset)
        return self

    def rotate(self, angle):
        for x in self.items:
            x.rotate(angle)
        return self

class Svg(Transformable):
    '''SVG class: use parse to parse a file'''
    def __init__(self, filename=None):
        Transformable.__init__(self)
        if filename:
            self.parse(filename)

    def parse(self, filename):
        self.filename = filename
        tree = etree.parse(filename)
        self.root = tree.getroot()
        if self.root.tag[-3:] != 'svg':
            raise TypeError('file %s does not seem to be a valid SVG file', filename)
        self.ns = self.root.tag[:-3]

        # Parse XML elements hierarchically with groups <g>
        self.addGroup(self.items, self.root)

        self.transform()

       # Flatten XML tree into a one dimension list
        self.flatten()

    def addGroup(self, group, element):
        for elt in element:
            if elt.tag == self.ns + 'g':
                g = Group(elt)
                # Append to parent group before looking for child elements
                # because Group.append() applies transformations
                # We need to record transformation to propagate to children
                group.append(g)
                self.addGroup(g, elt)
            elif elt.tag == self.ns + 'path':
                group.append(Path(elt))
            elif elt.tag == self.ns + 'circle':
                group.append(Circle(elt))
            else:
                print('Unsupported element: ' + elt.tag)
                #group.append(elt.tag[len(self.ns):])


    def flatten(self):
        self.drawing = []
        for i in self.items:
            if isinstance(i, Group):
                self.drawing += i.flatten()
            else:
                self.drawing.append(i)

    def title(self):
        t = self.root.find(self.ns + 'title')
        if t is not None:
            return t
        else:
            return self.filename.split('.')[0]


class Group(Transformable):
    '''Handle svg <g> elements'''
    def __init__(self, elt=None):
        Transformable.__init__(self, elt)
        if elt is not None:
            self.ident = elt.get('id')

    def append(self, item):
        item.matrix = self.matrix * item.matrix
        self.items.append(item)

    def __repr__(self):
        return 'Group id ' + self.ident + ':\n' + repr(self.items) + '\n'

    def flatten(self):
        ret = []
        for i in self.items:
            if isinstance(i, Group):
                ret += i.flatten()
            else:
                ret.append(i)
        return ret

class Matrix:
    ''' SVG transformation matrix and its operations
    a SVG matrix is represented as a list of 6 values [a, b, c, d, e, f]
    (named vect hereafter) which represent the 3x3 matrix
    ((a, c, e)
     (b, d, f)
     (0, 0, 1))
    see http://www.w3.org/TR/SVG/coords.html#EstablishingANewUserSpace '''

    def __init__(self, vect=[1, 0, 0, 1, 0, 0]):
        # Unit transformation vect by default
        if len(vect) != 6:
            raise ValueError("Bad vect size %d" % len(vect))
        self.vect = list(vect)

    def __mul__(self, other):
        '''Matrix multiplication'''
        if isinstance(other, Matrix):
            a = self.vect[0] * other.vect[0] + self.vect[2] * other.vect[1]
            b = self.vect[1] * other.vect[0] + self.vect[3] * other.vect[1]
            c = self.vect[0] * other.vect[2] + self.vect[2] * other.vect[3]
            d = self.vect[1] * other.vect[2] + self.vect[3] * other.vect[3]
            e = self.vect[0] * other.vect[4] + self.vect[2] * other.vect[5] \
                    + self.vect[4]
            f = self.vect[1] * other.vect[4] + self.vect[3] * other.vect[5] \
                    + self.vect[5]
            return Matrix([a, b, c, d, e, f])

        elif isinstance(other, Point):
            x = other.x * self.vect[0] + other.y * self.vect[2] + self.vect[4]
            y = other.x * self.vect[1] + other.y * self.vect[3] + self.vect[5]
            return Point(x,y)

        else:
            return NotImplemented

    def __str__(self):
        return str(self.vect)


COMMANDS = 'MmZzLlHhVvCcSsQqTtAa'

class Path(Transformable):
    '''SVG <path>'''

    def __init__(self, elt=None):
        Transformable.__init__(self, elt)
        if elt is not None:
            self.ident = elt.get('id')
            self.style = elt.get('style')
            self.parse(elt.get('d'))

    def parse(self, pathstr):
        """Parse path string and build elements list"""

        # (?:...) : non-capturing version of regular parentheses
        pathlst = re.findall(r"([+-]?\ *\d+(?:\.\d*)?|\.\d+|\ *[%s]\ *)"
                % COMMANDS, pathstr)

        pathlst.reverse()

        command = None
        current_pt = Point(0,0)
        start_pt = None

        while pathlst:
            if pathlst[-1].strip() in COMMANDS:
                last_command = command
                command = pathlst.pop().strip()
                absolute = (command == command.upper())
                command = command.upper()
            else:
                if command is None:
                    raise ValueError("No command found at %d" % len(pathlst))

            if command == 'M':
            # MoveTo
                x = pathlst.pop()
                y = pathlst.pop()
                pt = Point(float(x), float(y))
                if absolute:
                    current_pt = pt
                else:
                    current_pt += pt
                start_pt = current_pt

                self.items.append(MoveTo(current_pt))

                # MoveTo with multiple coordinates means LineTo
                command = 'L'

            elif command == 'Z':
            # Close Path
                l = Line(current_pt, start_pt)
                self.items.append(l)


            elif command in 'LHV':
            # LineTo, Horizontal & Vertical line
                # extra coord for H,V
                if absolute:
                    x,y = current_pt.coord()
                else:
                    x,y = (0,0)

                if command in 'LH':
                    x = pathlst.pop()
                if command in 'LV':
                    y = pathlst.pop()

                pt = Point(float(x), float(y))
                if not absolute:
                    pt += current_pt

                self.items.append(Line(current_pt, pt))
                current_pt = pt

            elif command in 'CQ':
                dimension = {'Q':3, 'C':4}
                bezier_pts = []
                bezier_pts.append(current_pt)
                for i in range(1,dimension[command]):
                    x = pathlst.pop()
                    y = pathlst.pop()
                    pt = Point(float(x), float(y))
                    if not absolute:
                        pt += current_pt
                    bezier_pts.append(pt)

                self.items.append(Bezier(bezier_pts))
                current_pt = pt

            elif command in 'TS':
                # number of points to read
                nbpts = {'T':1, 'S':2}
                # the control point, from previous Bezier to mirror
                ctrlpt = {'T':1, 'S':2}
                # last command control
                last = {'T': 'QT', 'S':'CS'}

                bezier_pts = []
                bezier_pts.append(current_pt)

                if last_command in last[command]:
                    pt0 = self.items[-1].control_point(ctrlpt[command])
                else:
                    pt0 = current_pt
                pt1 = current_pt
                # Symetrical of pt1 against pt0
                bezier_pts.append(pt1 + pt1 - pt0)

                for i in range(0,nbpts[command]):
                    x = pathlst.pop()
                    y = pathlst.pop()
                    pt = Point(float(x), float(y))
                    if not absolute:
                        pt += current_pt
                    bezier_pts.append(pt)

                self.items.append(Bezier(bezier_pts))
                current_pt = pt

            elif command == 'A':
                for i in range(0,7):
                    pathlst.pop()
                # TODO

            else:
                pathlst.pop()

    def __str__(self):
        return '\n'.join(str(x) for x in self.items)

    def __repr__(self):
        return 'Path id ' + self.ident

    def segments(self, precision=0):
        '''Return a list of segments, each segment is ended by a MoveTo.
           A segment is a list of Points'''
        ret = []
        seg = []
        for x in self.items:
            if isinstance(x, MoveTo):
                if seg != []:
                    ret.append(seg)
                    seg = []
            else:
                seg += x.segments(precision)
        ret.append(seg)
        return ret

    def simplify(self, precision):
        '''Simplify segment with precision:
           Remove any point which are ~aligned'''
        ret = []
        for seg in self.segments(precision):
            ret.append(simplify_segment(seg, precision))

        return ret

class Point:
    def __init__(self, x=0, y=0):
        '''A Point is defined either by a tuple/list of length 2 or
           by 2 coordinates'''
        if (isinstance(x, tuple) or isinstance(x, list)) and len(x) == 2:
            self.x = x[0]
            self.y = x[1]
        elif isinstance(x, numbers.Real) and isinstance(y, numbers.Real):
            self.x = x
            self.y = y
        else:
            raise TypeError("A Point is defined by 2 numbers or a tuple")

    def __add__(self, other):
        '''Add 2 points by adding coordinates.
        Try to convert other to Point if necessary'''
        if not isinstance(other, Point):
            try: other = Point(other)
            except: return NotImplemented
        return Point(self.x + other.x, self.y + other.y)

    def __sub__(self, other):
        if not isinstance(other, Point):
            try: other = Point(other)
            except: return NotImplemented
        return Point(self.x - other.x, self.y - other.y)

    def __mul__(self, other):
        if not isinstance(other, numbers.Real):
            return NotImplemented
        return Point(self.x * other, self.y * other)
    def __rmul__(self, other):
        return self.__mul__(other)

    def __eq__(self, other):
        if not isinstance(other, Point):
            try: other = Point(other)
            except: return NotImplemented
        return (self.x == other.x) and (self.y == other.y)

    def __repr__(self):
        return '(' + format(self.x,'.3f') + ',' + format( self.y,'.3f') + ')'

    def __str__(self):
        return self.__repr__();

    def coord(self):
        '''Return the point tuple (x,y)'''
        return (self.x, self.y)

    def length(self):
        '''Vector length, Pythagoras theorem'''
        return math.sqrt(self.x ** 2 + self.y ** 2)

    def rot(self, angle):
        '''Rotate vector [Origin,self] '''
        if not isinstance(angle, Angle):
            try: angle = Angle(angle)
            except: return NotImplemented
        x = self.x * angle.cos - self.y * angle.sin
        y = self.x * angle.sin + self.y * angle.cos
        return Point(x,y)


class Angle:
    '''Define a trigonometric angle [of a vector] '''
    def __init__(self, arg):
        if isinstance(arg, numbers.Real):
        # We precompute sin and cos for rotations
            self.angle = arg
            self.cos = math.cos(self.angle)
            self.sin = math.sin(self.angle)
        elif isinstance(arg, Point):
        # Point angle is the trigonometric angle of the vector [origin, Point]
            pt = arg
            try:
                self.cos = pt.x/pt.length()
                self.sin = pt.y/pt.length()
            except ZeroDivisionError:
                self.cos = 1
                self.sin = 0

            self.angle = math.acos(self.cos)
            if self.sin < 0:
                self.angle = -self.angle
        else:
            raise TypeError("Angle is defined by a number or a Point")

    def __neg__(self):
        return Angle(Point(self.cos, -self.sin))

class Line:
    '''A line is an object defined by 2 points'''
    def __init__(self, start, end):
        self.start = start
        self.end = end

    def __str__(self):
        return 'Line from ' + str(self.start) + ' to ' + str(self.end)

    def segments(self, precision=0):
        ''' Line segments is simply the segment start -> end'''
        return [self.start, self.end]

    def length(self):
        '''Line length, Pythagoras theorem'''
        s = self.end - self.start
        return math.sqrt(s.x ** 2 + s.y ** 2)

    def pdistance(self, p):
        '''Perpendicular distance between this Line and a given Point p'''
        if not isinstance(p, Point):
            return NotImplemented

        if self.start == self.end:
        # Distance from a Point to another Point is length of a line
            return Line(self.start, p).length()

        s = self.end - self.start
        if s.x == 0:
        # Vertical Line => pdistance is the difference of abscissa
            return abs(self.start.x - p.x)
        else:
        # That's 2-D perpendicular distance formulae (ref: Wikipedia)
            slope = s.y/s.x
            # intercept: Crossing with ordinate y-axis
            intercept = self.start.y - (slope * self.start.x)
            return abs(slope * p.x - p.y + intercept) / math.sqrt(slope ** 2 + 1)


    def bbox(self):
        if self.start.x < self.end.x:
            xmin = self.start.x
            xmax = self.end.x
        else:
            xmin = self.end.x
            xmax = self.start.x
        if self.start.y < self.end.y:
            ymin = self.start.y
            ymax = self.end.y
        else:
            ymin = self.end.y
            ymax = self.start.y
        return (Point(xmin,ymin),Point(xmax,ymax))

    def transform(self, matrix):
        self.start = matrix * self.start
        self.end = matrix * self.end

    def scale(self, ratio):
        self.start *= ratio
        self.end *= ratio
    def translate(self, offset):
        self.start += offset
        self.end += offset
    def rotate(self, angle):
        self.start = self.start.rot(angle)
        self.end = self.end.rot(angle)

class Bezier:
    '''Bezier curve class
       A Bezier curve is defined by its control points
       Its dimension is equal to the number of control points
       Note that SVG only support dimension 3 and 4 Bezier curve, respectively
       Quadratic and Cubic Bezier curve'''
    def __init__(self, pts):
        self.pts = list(pts)
        self.dimension = len(pts)

    def __str__(self):
        return 'Bezier' + str(self.dimension) + \
                ' : ' + ", ".join([str(x) for x in self.pts])

    def control_point(self, n):
        if n >= self.dimension:
            raise LookupError('Index is larger than Bezier curve dimension')
        else:
            return self.pts[n]

    def rlength(self):
        '''Rough Bezier length: length of control point segments'''
        pts = list(self.pts)
        l = 0.0
        p1 = pts.pop()
        while pts:
            p2 = pts.pop()
            l += Line(p1, p2).length()
            p1 = p2
        return l

    def bbox(self):
        return self.rbbox()

    def rbbox(self):
        '''Rough bounding box: return the bounding box (P1,P2) of the Bezier
        _control_ points'''
        xmin = None
        xmax = None
        ymin = None
        ymax = None
        for pt in self.pts:
            if xmin == None or pt.x < xmin:
                xmin = pt.x
            if ymin == None or pt.y < ymin:
                ymin = pt.y
            if xmax == None or pt.x > xmax:
                xmax = pt.x
            if ymax == None or pt.y > ymax:
                ymax = pt.y

        return (Point(xmin,ymin), Point(xmax,ymax))

    def segments(self, precision=0):
        '''Return a polyline approximation ("segments") of the Bezier curve
           precision is the minimum significative length of a segment'''
        segments = []
        # n is the number of Bezier points to draw according to precision
        if precision != 0:
            n = int(self.rlength() / precision) + 1
        else:
            n = 1000
        if n < 10: n = 10
        if n > 1000 : n = 1000

        for t in range(0, n):
            segments.append(self._bezierN(float(t)/n))
        return segments

    def _bezier1(self, p0, p1, t):
        '''Bezier curve, one dimension
        Compute the Point corresponding to a linear Bezier curve between
        p0 and p1 at "time" t '''
        pt = p0 + t * (p1 - p0)
        return pt

    def _bezierN(self, t):
        '''Bezier curve, Nth dimension
        Compute the point of the Nth dimension Bezier curve at "time" t'''
        # We reduce the N Bezier control points by computing the linear Bezier
        # point of each control point segment, creating N-1 control points
        # until we reach one single point
        res = list(self.pts)
        # We store the resulting Bezier points in res[], recursively
        for n in range(self.dimension, 1, -1):
            # For each control point of nth dimension,
            # compute linear Bezier point a t
            for i in range(0,n-1):
                res[i] = self._bezier1(res[i], res[i+1], t)
        return res[0]

    def transform(self, matrix):
        self.pts = [matrix * x for x in self.pts]

    def scale(self, ratio):
        self.pts = [x * ratio for x in self.pts]
    def translate(self, offset):
        self.pts = [x + offset for x in self.pts]
    def rotate(self, angle):
        self.pts = [x.rot(angle) for x in self.pts]

class MoveTo:
    def __init__(self, dest):
        self.dest = dest

    def bbox(self):
        return (self.dest, self.dest)

    def transform(self, matrix):
        self.dest = matrix * self.dest

    def scale(self, ratio):
        self.dest *= ratio
    def translate(self, offset):
        self.dest += offset
    def rotate(self, angle):
        self.dest = self.dest.rot(angle)

class Circle(Transformable):
    '''SVG <circle>'''
    def __init__(self, elt=None):
        Transformable.__init__(self, elt)
        if elt is not None:
            self.center = Point(float(elt.get('cx')), float(elt.get('cy')))
            self.radius = float(elt.get('r'))
            self.style = elt.get('style')
            self.ident = elt.get('id')

    def __repr__(self):
        return 'circle id ' + self.ident

    def bbox(self):
        '''Bounding box'''
        pmin = self.center - Point(self.radius, self.radius)
        pmax = self.center + Point(self.radius, self.radius)
        return (pmin, pmax)

    def transform(self, matrix):
        self.center = self.matrix * self.center

    def scale(self, ratio):
        self.center *= ratio
        self.radius *= ratio
    def translate(self, offset):
        self.center += offset
    def rotate(self, angle):
        self.center = self.center.rot(angle)

    def segments(self, precision=0):
        return self

    def simplify(self, precision):
        return self

def simplify_segment(segment, epsilon):
    '''Ramer-Douglas-Peucker algorithm'''
    if len(segment) < 3 or epsilon <= 0:
        return segment[:]

    l = Line(segment[0], segment[-1]) # Longest line

    # Find the furthest point from the line
    maxDist = 0
    index = None
    for i,p in enumerate(segment[1:]):
        dist = l.pdistance(p)
        if (dist > maxDist):
            maxDist = dist
            index = i+1 # enumerate starts at segment[1]

    if maxDist > epsilon:
        # Recursively call with segment splited in 2 on its furthest point
        r1 = simplify_segment(segment[:index+1], epsilon)
        r2 = simplify_segment(segment[index:], epsilon)
        # Remove redundant 'middle' Point
        return r1[:-1] + r2
    else:
        return [segment[0], segment[-1]]

svg.test.py

import sys, os
import svg
import Image, ImageDraw

f = open(sys.argv[1])
line = f.readline()

p = svg.Path(line)

im = Image.new("RGB", (800,800), "white")
draw = ImageDraw.Draw(im)

red = (255,0,0)
green = (0,255,0)

for l in p.segments(1):
    draw.line([(1*x).coord() for x in l], fill=red)
#for l in p.simplify(5):
#    draw.point([(1*x).coord() for x in l], fill=green)
draw.rectangle([pt.coord() for pt in p.bbox()], outline='blue')
#im.save(os.path.expanduser("~/public_html/bezier.png"))
im.show()

Hello me,

It would be better to use Ramer–Douglas–Peucker algorithm for simplification.
See:
http://en.wikipedia.org/wiki/Ramer-Douglas-Peucker_algorithm
http://karthaus.nl/rdp/js/rdp.js
http://mourner.github.io/simplify-js/
https://github.com/omarestrella/simplify.py/blob/master/simplify.py