212 lines
6.9 KiB
Python
212 lines
6.9 KiB
Python
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"""
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simplepath.py
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functions for digesting paths into a simple list structure
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Copyright (C) 2005 Aaron Spike, aaron@ekips.org
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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"""
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import re, math
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def lexPath(d):
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"""
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returns and iterator that breaks path data
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identifies command and parameter tokens
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"""
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offset = 0
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length = len(d)
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delim = re.compile(r'[ \t\r\n,]+')
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command = re.compile(r'[MLHVCSQTAZmlhvcsqtaz]')
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parameter = re.compile(r'(([-+]?[0-9]+(\.[0-9]*)?|[-+]?\.[0-9]+)([eE][-+]?[0-9]+)?)')
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while 1:
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m = delim.match(d, offset)
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if m:
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offset = m.end()
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if offset >= length:
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break
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m = command.match(d, offset)
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if m:
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yield [d[offset:m.end()], True]
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offset = m.end()
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continue
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m = parameter.match(d, offset)
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if m:
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yield [d[offset:m.end()], False]
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offset = m.end()
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continue
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#TODO: create new exception
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raise Exception('Invalid path data!')
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'''
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pathdefs = {commandfamily:
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[
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implicitnext,
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#params,
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[casts,cast,cast],
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[coord type,x,y,0]
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]}
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'''
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pathdefs = {
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'M':['L', 2, [float, float], ['x','y']],
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'L':['L', 2, [float, float], ['x','y']],
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'H':['H', 1, [float], ['x']],
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'V':['V', 1, [float], ['y']],
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'C':['C', 6, [float, float, float, float, float, float], ['x','y','x','y','x','y']],
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'S':['S', 4, [float, float, float, float], ['x','y','x','y']],
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'Q':['Q', 4, [float, float, float, float], ['x','y','x','y']],
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'T':['T', 2, [float, float], ['x','y']],
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'A':['A', 7, [float, float, float, int, int, float, float], ['r','r','a',0,'s','x','y']],
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'Z':['L', 0, [], []]
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}
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def parsePath(d):
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"""
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Parse SVG path and return an array of segments.
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Removes all shorthand notation.
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Converts coordinates to absolute.
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"""
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retval = []
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lexer = lexPath(d)
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pen = (0.0,0.0)
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subPathStart = pen
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lastControl = pen
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lastCommand = ''
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while 1:
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try:
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token, isCommand = next(lexer)
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except StopIteration:
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break
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params = []
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needParam = True
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if isCommand:
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if not lastCommand and token.upper() != 'M':
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raise Exception('Invalid path, must begin with moveto.')
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else:
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command = token
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else:
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#command was omited
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#use last command's implicit next command
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needParam = False
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if lastCommand:
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if lastCommand.isupper():
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command = pathdefs[lastCommand][0]
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else:
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command = pathdefs[lastCommand.upper()][0].lower()
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else:
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raise Exception('Invalid path, no initial command.')
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numParams = pathdefs[command.upper()][1]
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while numParams > 0:
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if needParam:
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try:
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token, isCommand = next(lexer)
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if isCommand:
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raise Exception('Invalid number of parameters')
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except StopIteration:
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raise Exception('Unexpected end of path')
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cast = pathdefs[command.upper()][2][-numParams]
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param = cast(token)
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if command.islower():
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if pathdefs[command.upper()][3][-numParams]=='x':
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param += pen[0]
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elif pathdefs[command.upper()][3][-numParams]=='y':
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param += pen[1]
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params.append(param)
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needParam = True
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numParams -= 1
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#segment is now absolute so
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outputCommand = command.upper()
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#Flesh out shortcut notation
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if outputCommand in ('H','V'):
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if outputCommand == 'H':
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params.append(pen[1])
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if outputCommand == 'V':
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params.insert(0,pen[0])
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outputCommand = 'L'
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if outputCommand in ('S','T'):
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params.insert(0,pen[1]+(pen[1]-lastControl[1]))
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params.insert(0,pen[0]+(pen[0]-lastControl[0]))
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if outputCommand == 'S':
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outputCommand = 'C'
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if outputCommand == 'T':
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outputCommand = 'Q'
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#current values become "last" values
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if outputCommand == 'M':
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subPathStart = tuple(params[0:2])
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pen = subPathStart
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if outputCommand == 'Z':
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pen = subPathStart
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else:
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pen = tuple(params[-2:])
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if outputCommand in ('Q','C'):
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lastControl = tuple(params[-4:-2])
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else:
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lastControl = pen
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lastCommand = command
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retval.append([outputCommand,params])
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return retval
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def formatPath(a):
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"""Format SVG path data from an array"""
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return "".join([cmd + " ".join([str(p) for p in params]) for cmd, params in a])
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def translatePath(p, x, y):
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for cmd,params in p:
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defs = pathdefs[cmd]
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for i in range(defs[1]):
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if defs[3][i] == 'x':
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params[i] += x
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elif defs[3][i] == 'y':
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params[i] += y
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def scalePath(p, x, y):
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for cmd,params in p:
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defs = pathdefs[cmd]
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for i in range(defs[1]):
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if defs[3][i] == 'x':
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params[i] *= x
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elif defs[3][i] == 'y':
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params[i] *= y
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elif defs[3][i] == 'r': # radius parameter
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params[i] *= x
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elif defs[3][i] == 's': # sweep-flag parameter
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if x*y < 0:
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params[i] = 1 - params[i]
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elif defs[3][i] == 'a': # x-axis-rotation angle
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if y < 0:
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params[i] = - params[i]
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def rotatePath(p, a, cx = 0, cy = 0):
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if a == 0:
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return p
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for cmd,params in p:
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defs = pathdefs[cmd]
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for i in range(defs[1]):
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if defs[3][i] == 'x':
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x = params[i] - cx
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y = params[i + 1] - cy
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r = math.sqrt((x**2) + (y**2))
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if r != 0:
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theta = math.atan2(y, x) + a
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params[i] = (r * math.cos(theta)) + cx
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params[i + 1] = (r * math.sin(theta)) + cy
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# vim: expandtab shiftwidth=4 tabstop=8 softtabstop=4 fileencoding=utf-8 textwidth=99
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