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mightyscape-1.1-deprecated/extensions/fablabchemnitz/svgpathtools/parser.py
2020-08-30 12:36:33 +02:00

197 lines
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Python

"""This submodule contains the path_parse() function used to convert SVG path
element d-strings into svgpathtools Path objects.
Note: This file was taken (nearly) as is from the svg.path module
(v 2.0)."""
# External dependencies
from __future__ import division, absolute_import, print_function
import re
# Internal dependencies
from .path import Path, Line, QuadraticBezier, CubicBezier, Arc
COMMANDS = set('MmZzLlHhVvCcSsQqTtAa')
UPPERCASE = set('MZLHVCSQTA')
COMMAND_RE = re.compile("([MmZzLlHhVvCcSsQqTtAa])")
FLOAT_RE = re.compile("[-+]?[0-9]*\.?[0-9]+(?:[eE][-+]?[0-9]+)?")
def _tokenize_path(pathdef):
for x in COMMAND_RE.split(pathdef):
if x in COMMANDS:
yield x
for token in FLOAT_RE.findall(x):
yield token
def parse_path(pathdef, current_pos=0j):
# In the SVG specs, initial movetos are absolute, even if
# specified as 'm'. This is the default behavior here as well.
# But if you pass in a current_pos variable, the initial moveto
# will be relative to that current_pos. This is useful.
elements = list(_tokenize_path(pathdef))
# Reverse for easy use of .pop()
elements.reverse()
segments = Path()
start_pos = None
command = None
while elements:
if elements[-1] in COMMANDS:
# New command.
last_command = command # Used by S and T
command = elements.pop()
absolute = command in UPPERCASE
command = command.upper()
else:
# If this element starts with numbers, it is an implicit command
# and we don't change the command. Check that it's allowed:
if command is None:
raise ValueError("Unallowed implicit command in %s, position %s" % (
pathdef, len(pathdef.split()) - len(elements)))
if command == 'M':
# Moveto command.
x = elements.pop()
y = elements.pop()
pos = float(x) + float(y) * 1j
if absolute:
current_pos = pos
else:
current_pos += pos
# when M is called, reset start_pos
# This behavior of Z is defined in svg spec:
# http://www.w3.org/TR/SVG/paths.html#PathDataClosePathCommand
start_pos = current_pos
# Implicit moveto commands are treated as lineto commands.
# So we set command to lineto here, in case there are
# further implicit commands after this moveto.
command = 'L'
elif command == 'Z':
# Close path
if not (current_pos == start_pos):
segments.append(Line(current_pos, start_pos))
segments.closed = True
current_pos = start_pos
start_pos = None
command = None # You can't have implicit commands after closing.
elif command == 'L':
x = elements.pop()
y = elements.pop()
pos = float(x) + float(y) * 1j
if not absolute:
pos += current_pos
segments.append(Line(current_pos, pos))
current_pos = pos
elif command == 'H':
x = elements.pop()
pos = float(x) + current_pos.imag * 1j
if not absolute:
pos += current_pos.real
segments.append(Line(current_pos, pos))
current_pos = pos
elif command == 'V':
y = elements.pop()
pos = current_pos.real + float(y) * 1j
if not absolute:
pos += current_pos.imag * 1j
segments.append(Line(current_pos, pos))
current_pos = pos
elif command == 'C':
control1 = float(elements.pop()) + float(elements.pop()) * 1j
control2 = float(elements.pop()) + float(elements.pop()) * 1j
end = float(elements.pop()) + float(elements.pop()) * 1j
if not absolute:
control1 += current_pos
control2 += current_pos
end += current_pos
segments.append(CubicBezier(current_pos, control1, control2, end))
current_pos = end
elif command == 'S':
# Smooth curve. First control point is the "reflection" of
# the second control point in the previous path.
if last_command not in 'CS':
# If there is no previous command or if the previous command
# was not an C, c, S or s, assume the first control point is
# coincident with the current point.
control1 = current_pos
else:
# The first control point is assumed to be the reflection of
# the second control point on the previous command relative
# to the current point.
control1 = current_pos + current_pos - segments[-1].control2
control2 = float(elements.pop()) + float(elements.pop()) * 1j
end = float(elements.pop()) + float(elements.pop()) * 1j
if not absolute:
control2 += current_pos
end += current_pos
segments.append(CubicBezier(current_pos, control1, control2, end))
current_pos = end
elif command == 'Q':
control = float(elements.pop()) + float(elements.pop()) * 1j
end = float(elements.pop()) + float(elements.pop()) * 1j
if not absolute:
control += current_pos
end += current_pos
segments.append(QuadraticBezier(current_pos, control, end))
current_pos = end
elif command == 'T':
# Smooth curve. Control point is the "reflection" of
# the second control point in the previous path.
if last_command not in 'QT':
# If there is no previous command or if the previous command
# was not an Q, q, T or t, assume the first control point is
# coincident with the current point.
control = current_pos
else:
# The control point is assumed to be the reflection of
# the control point on the previous command relative
# to the current point.
control = current_pos + current_pos - segments[-1].control
end = float(elements.pop()) + float(elements.pop()) * 1j
if not absolute:
end += current_pos
segments.append(QuadraticBezier(current_pos, control, end))
current_pos = end
elif command == 'A':
radius = float(elements.pop()) + float(elements.pop()) * 1j
rotation = float(elements.pop())
arc = float(elements.pop())
sweep = float(elements.pop())
end = float(elements.pop()) + float(elements.pop()) * 1j
if not absolute:
end += current_pos
segments.append(Arc(current_pos, radius, rotation, arc, sweep, end))
current_pos = end
return segments