Basic support for importing SVG. Via shell only at this time. See issue #179.
This commit is contained in:
Juan Pablo Caram
268
svgparse.py
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268
svgparse.py
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############################################################
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# FlatCAM: 2D Post-processing for Manufacturing #
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# http://flatcam.org #
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# Author: Juan Pablo Caram (c) #
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# Date: 12/18/2015 #
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# MIT Licence #
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############################################################
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import xml.etree.ElementTree as ET
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import re
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import itertools
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from svg.path import Path, Line, Arc, CubicBezier, QuadraticBezier, parse_path
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from shapely.geometry import LinearRing, LineString
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from shapely.affinity import translate, rotate, scale, skew, affine_transform
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def path2shapely(path, res=1.0):
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"""
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Converts an svg.path.Path into a Shapely
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LinearRing or LinearString.
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:rtype : LinearRing
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:rtype : LineString
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:param path: svg.path.Path instance
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:param res: Resolution (minimum step along path)
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:return: Shapely geometry object
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"""
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points = []
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for component in path:
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# Line
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if isinstance(component, Line):
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start = component.start
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x, y = start.real, start.imag
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if len(points) == 0 or points[-1] != (x, y):
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points.append((x, y))
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end = component.end
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points.append((end.real, end.imag))
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continue
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# Arc, CubicBezier or QuadraticBezier
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if isinstance(component, Arc) or \
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isinstance(component, CubicBezier) or \
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isinstance(component, QuadraticBezier):
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length = component.length(res / 10.0)
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steps = int(length / res + 0.5)
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frac = 1.0 / steps
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print length, steps, frac
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for i in range(steps):
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point = component.point(i * frac)
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x, y = point.real, point.imag
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if len(points) == 0 or points[-1] != (x, y):
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points.append((x, y))
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end = component.point(1.0)
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points.append((end.real, end.imag))
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continue
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print "I don't know what this is:", component
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continue
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if path.closed:
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return LinearRing(points)
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else:
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return LineString(points)
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def svgrect2shapely(rect):
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w = float(rect.get('width'))
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h = float(rect.get('height'))
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x = float(rect.get('x'))
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y = float(rect.get('y'))
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pts = [
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(x, y), (x + w, y), (x + w, y + h), (x, y + h), (x, y)
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]
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return LinearRing(pts)
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def getsvggeo(node):
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"""
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Extracts and flattens all geometry from an SVG node
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into a list of Shapely geometry.
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:param node:
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:return:
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"""
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kind = re.search('(?:\{.*\})?(.*)$', node.tag).group(1)
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geo = []
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# Recurse
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if len(node) > 0:
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for child in node:
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subgeo = getsvggeo(child)
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if subgeo is not None:
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geo += subgeo
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# Parse
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elif kind == 'path':
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print "***PATH***"
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P = parse_path(node.get('d'))
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P = path2shapely(P)
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geo = [P]
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elif kind == 'rect':
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print "***RECT***"
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R = svgrect2shapely(node)
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geo = [R]
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else:
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print "Unknown kind:", kind
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geo = None
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# Transformations
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if 'transform' in node.attrib:
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trstr = node.get('transform')
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trlist = parse_svg_transform(trstr)
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print trlist
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# Transformations are applied in reverse order
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for tr in trlist[::-1]:
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if tr[0] == 'translate':
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geo = [translate(geoi, tr[1], tr[2]) for geoi in geo]
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elif tr[0] == 'scale':
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geo = [scale(geoi, tr[0], tr[1], origin=(0, 0))
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for geoi in geo]
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elif tr[0] == 'rotate':
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geo = [rotate(geoi, tr[1], origin=(tr[2], tr[3]))
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for geoi in geo]
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elif tr[0] == 'skew':
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geo = [skew(geoi, tr[1], tr[2], origin=(0, 0))
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for geoi in geo]
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elif tr[0] == 'matrix':
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geo = [affine_transform(geoi, tr[1:]) for geoi in geo]
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else:
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raise Exception('Unknown transformation: %s', tr)
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return geo
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def parse_svg_transform(trstr):
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"""
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Parses an SVG transform string into a list
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of transform names and their parameters.
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Possible transformations are:
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* Translate: translate(<tx> [<ty>]), which specifies
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a translation by tx and ty. If <ty> is not provided,
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it is assumed to be zero. Result is
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['translate', tx, ty]
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* Scale: scale(<sx> [<sy>]), which specifies a scale operation
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by sx and sy. If <sy> is not provided, it is assumed to be
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equal to <sx>. Result is: ['scale', sx, sy]
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* Rotate: rotate(<rotate-angle> [<cx> <cy>]), which specifies
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a rotation by <rotate-angle> degrees about a given point.
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If optional parameters <cx> and <cy> are not supplied,
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the rotate is about the origin of the current user coordinate
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system. Result is: ['rotate', rotate-angle, cx, cy]
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* Skew: skewX(<skew-angle>), which specifies a skew
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transformation along the x-axis. skewY(<skew-angle>), which
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specifies a skew transformation along the y-axis.
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Result is ['skew', angle-x, angle-y]
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* Matrix: matrix(<a> <b> <c> <d> <e> <f>), which specifies a
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transformation in the form of a transformation matrix of six
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values. matrix(a,b,c,d,e,f) is equivalent to applying the
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transformation matrix [a b c d e f]. Result is
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['matrix', a, b, c, d, e, f]
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:param trstr: SVG transform string.
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:type trstr: str
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:return: List of transforms.
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:rtype: list
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"""
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trlist = []
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assert isinstance(trstr, str)
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trstr = trstr.strip(' ')
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num_re_str = r'[\+\-]?[0-9\.e]+' # TODO: Negative exponents missing
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comma_or_space_re_str = r'(?:(?:\s+)|(?:\s*,\s*))'
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translate_re_str = r'translate\s*\(\s*(' + \
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num_re_str + r')' + \
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r'(?:' + comma_or_space_re_str + \
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r'(' + num_re_str + r'))?\s*\)'
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scale_re_str = r'scale\s*\(\s*(' + \
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num_re_str + r')' + \
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r'(?:' + comma_or_space_re_str + \
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r'(' + num_re_str + r'))?\s*\)'
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skew_re_str = r'skew([XY])\s*\(\s*(' + \
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num_re_str + r')\s*\)'
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rotate_re_str = r'rotate\s*\(\s*(' + \
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num_re_str + r')' + \
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r'(?:' + comma_or_space_re_str + \
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r'(' + num_re_str + r')' + \
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comma_or_space_re_str + \
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r'(' + num_re_str + r'))?\*\)'
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matrix_re_str = r'matrix\s*\(\s*' + \
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r'(' + num_re_str + r')' + comma_or_space_re_str + \
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r'(' + num_re_str + r')' + comma_or_space_re_str + \
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r'(' + num_re_str + r')' + comma_or_space_re_str + \
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r'(' + num_re_str + r')' + comma_or_space_re_str + \
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r'(' + num_re_str + r')' + comma_or_space_re_str + \
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r'(' + num_re_str + r')\s*\)'
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while len(trstr) > 0:
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match = re.search(r'^' + translate_re_str, trstr)
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if match:
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trlist.append([
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'translate',
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float(match.group(1)),
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float(match.group(2)) if match.group else 0.0
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])
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trstr = trstr[len(match.group(0)):].strip(' ')
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continue
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match = re.search(r'^' + scale_re_str, trstr)
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if match:
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trlist.append([
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'translate',
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float(match.group(1)),
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float(match.group(2)) if match.group else float(match.group(1))
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])
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trstr = trstr[len(match.group(0)):].strip(' ')
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continue
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match = re.search(r'^' + skew_re_str, trstr)
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if match:
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trlist.append([
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'skew',
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float(match.group(2)) if match.group(1) == 'X' else 0.0,
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float(match.group(2)) if match.group(1) == 'Y' else 0.0
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])
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trstr = trstr[len(match.group(0)):].strip(' ')
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continue
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match = re.search(r'^' + rotate_re_str, trstr)
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if match:
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trlist.append([
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'rotate',
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float(match.group(1)),
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float(match.group(2)) if match.group(2) else 0.0,
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float(match.group(3)) if match.group(3) else 0.0
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])
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trstr = trstr[len(match.group(0)):].strip(' ')
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continue
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match = re.search(r'^' + matrix_re_str, trstr)
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if match:
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trlist.append(['matrix'] + [float(x) for x in match.groups()])
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trstr = trstr[len(match.group(0)):].strip(' ')
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continue
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raise Exception("Don't know how to parse: %s" % trstr)
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return trlist
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if __name__ == "__main__":
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tree = ET.parse('tests/svg/drawing.svg')
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root = tree.getroot()
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ns = re.search(r'\{(.*)\}', root.tag).group(1)
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print ns
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for geo in getsvggeo(root):
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print geo
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Reference in New Issue
Block a user