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# coding=utf-8
#
# Copyright (C) 2010 Nick Drobchenko, nick@cnc-club.ru
# Copyright (C) 2005 Aaron Spike, aaron@ekips.org
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
"""
Basic common utility functions for calculated things
"""
import os
import sys
import random
import re
import math
from argparse import ArgumentTypeError
from itertools import tee
ABORT_STATUS = -5
(X, Y) = range(2)
PY3 = sys.version_info[0] == 3
# pylint: disable=line-too-long
# Taken from https://www.w3.org/Graphics/SVG/1.1/paths.html#PathDataBNF
DIGIT_REX_PART = r"[0-9]"
DIGIT_SEQUENCE_REX_PART = rf"(?:{DIGIT_REX_PART}+)"
INTEGER_CONSTANT_REX_PART = DIGIT_SEQUENCE_REX_PART
SIGN_REX_PART = r"[+-]"
EXPONENT_REX_PART = rf"(?:[eE]{SIGN_REX_PART}?{DIGIT_SEQUENCE_REX_PART})"
FRACTIONAL_CONSTANT_REX_PART = rf"(?:{DIGIT_SEQUENCE_REX_PART}?\.{DIGIT_SEQUENCE_REX_PART}|{DIGIT_SEQUENCE_REX_PART}\.)"
FLOATING_POINT_CONSTANT_REX_PART = rf"(?:{FRACTIONAL_CONSTANT_REX_PART}{EXPONENT_REX_PART}?|{DIGIT_SEQUENCE_REX_PART}{EXPONENT_REX_PART})"
NUMBER_REX = re.compile(
rf"(?:{SIGN_REX_PART}?{FLOATING_POINT_CONSTANT_REX_PART}|{SIGN_REX_PART}?{INTEGER_CONSTANT_REX_PART})"
)
# pylint: enable=line-too-long
def _pythonpath():
for pth in os.environ.get("PYTHONPATH", "").split(":"):
if os.path.isdir(pth):
yield pth
def get_user_directory():
"""Return the user directory where extensions are stored.
.. versionadded:: 1.1"""
if "INKSCAPE_PROFILE_DIR" in os.environ:
return os.path.abspath(
os.path.expanduser(
os.path.join(os.environ["INKSCAPE_PROFILE_DIR"], "extensions")
)
)
home = os.path.expanduser("~")
for pth in _pythonpath():
if pth.startswith(home):
return pth
return None
def get_inkscape_directory():
"""Return the system directory where inkscape's core is.
.. versionadded:: 1.1"""
for pth in _pythonpath():
if os.path.isdir(os.path.join(pth, "inkex")):
return pth
raise ValueError("Unable to determine the location of Inkscape")
class KeyDict(dict):
"""
A normal dictionary, except asking for anything not in the dictionary
always returns the key itself. This is used for translation dictionaries.
"""
def __getitem__(self, key):
try:
return super().__getitem__(key)
except KeyError:
return key
def parse_percent(val: str):
"""Parse strings that are either values (i.e., '3.14159') or percentages
(i.e. '75%') to a float.
.. versionadded:: 1.2"""
val = val.strip()
if val.endswith("%"):
return float(val[:-1]) / 100
return float(val)
def Boolean(value):
"""ArgParser function to turn a boolean string into a python boolean"""
if value.upper() == "TRUE":
return True
if value.upper() == "FALSE":
return False
return None
def to_bytes(content):
"""Ensures the content is bytes
.. versionadded:: 1.1"""
if isinstance(content, bytes):
return content
return str(content).encode("utf8")
def debug(what):
"""Print debug message if debugging is switched on"""
errormsg(what)
return what
def do_nothing(*args, **kwargs): # pylint: disable=unused-argument
"""A blank function to do nothing
.. versionadded:: 1.1"""
def errormsg(msg):
"""Intended for end-user-visible error messages.
(Currently just writes to stderr with an appended newline, but could do
something better in future: e.g. could add markup to distinguish error
messages from status messages or debugging output.)
Note that this should always be combined with translation::
import inkex
...
inkex.errormsg(_("This extension requires two selected paths."))
"""
try:
sys.stderr.write(msg)
except TypeError:
sys.stderr.write(str(msg))
except UnicodeEncodeError:
# Python 2:
# Fallback for cases where sys.stderr.encoding is not Unicode.
# Python 3:
# This will not work as write() does not accept byte strings, but AFAIK
# we should never reach this point as the default error handler is
# 'backslashreplace'.
# This will be None by default if stderr is piped, so use ASCII as a
# last resort.
encoding = sys.stderr.encoding or "ascii"
sys.stderr.write(msg.encode(encoding, "backslashreplace"))
# Write '\n' separately to avoid dealing with different string types.
sys.stderr.write("\n")
class AbortExtension(Exception):
"""Raised to print a message to the user without backtrace"""
class DependencyError(NotImplementedError):
"""Raised when we need an external python module that isn't available"""
class FragmentError(Exception):
"""Raised when trying to do rooty things on an xml fragment"""
def to(kind): # pylint: disable=invalid-name
"""
Decorator which will turn a generator into a list, tuple or other object type.
"""
def _inner(call):
def _outer(*args, **kw):
return kind(call(*args, **kw))
return _outer
return _inner
def strargs(string, kind=float):
"""Returns a list of floats from a string
.. versionchanged:: 1.1
also splits at -(minus) signs by adding a space in front of the - sign
.. versionchanged:: 1.2
Full support for the `SVG Path data BNF
<https://www.w3.org/Graphics/SVG/1.1/paths.html#PathDataBNF>`_
"""
return [kind(val) for val in NUMBER_REX.findall(string)]
class classproperty: # pylint: disable=invalid-name, too-few-public-methods
"""Combine classmethod and property decorators"""
def __init__(self, func):
self.func = func
def __get__(self, obj, owner):
return self.func(owner)
def filename_arg(name):
"""Existing file to read or option used in script arguments"""
filename = os.path.abspath(os.path.expanduser(name))
if not os.path.isfile(filename):
raise ArgumentTypeError(f"File not found: {name}")
return filename
def pairwise(iterable, start=True):
"Iterate over a list with overlapping pairs (see itertools recipes)"
first, then = tee(iterable)
starter = [(None, next(then, None))]
if not start:
starter = []
return starter + list(zip(first, then))
EVAL_GLOBALS = {}
EVAL_GLOBALS.update(random.__dict__)
EVAL_GLOBALS.update(math.__dict__)
def math_eval(function, variable="x"):
"""Interpret a function string. All functions from math and random may be used.
.. versionadded:: 1.1
Returns:
a lambda expression if sucessful; otherwise None.
"""
try:
if function != "":
return eval(
f"lambda {variable}: " + (function.strip('"') or "t"), EVAL_GLOBALS, {}
)
# handle incomplete/invalid function gracefully
except SyntaxError:
pass
return None
def is_number(string):
"""Checks if a value is a number
.. versionadded:: 1.2"""
try:
float(string)
return True
except ValueError:
return False
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