""" Parse SVG path element d-strings into svgpathtools Path objects. This submodule contains the parse_path() function. 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 from typing import Optional, Sequence, TYPE_CHECKING import math import re import numpy as np import warnings # Internal dependencies from .path import Path if TYPE_CHECKING: # Imported for type annotations only; no XML is parsed here. from xml.etree.ElementTree import Element # The SVG number grammar. Stricter than float(), which also accepts # e.g. '1_0', 'nan', and non-ASCII digits. (The one deliberate # looseness: '1.' is accepted, though the grammar technically wants a # digit after the point.) _NUMBER_RE = re.compile(r'[+-]?([0-9]+(\.[0-9]*)?|\.[0-9]+)([eE][+-]?[0-9]+)?\Z') class SVGSyntaxWarning(UserWarning): """Category for warnings about invalid SVG syntax handled leniently.""" def parse_path(pathdef: str, current_pos: complex = 0j, tree_element: Optional['Element'] = None) -> Path: """Convert an SVG path element d-string into a Path object.""" return Path(pathdef, current_pos=current_pos, tree_element=tree_element) def _check_num_parsed_values(values: Sequence[float], allowed: Sequence[int], transform_substr: str) -> None: if not any(num == len(values) for num in allowed): if len(allowed) > 1: raise ValueError('Expected one of the following number of values {0}, ' 'but found {1} values in {2!r}: {3}' .format(allowed, len(values), transform_substr, values)) elif allowed[0] != 1: raise ValueError('Expected {0} values in {1!r}, found {2}: {3}' .format(allowed[0], transform_substr, len(values), values)) else: raise ValueError('Expected 1 value in {0!r}, found {1}: {2}' .format(transform_substr, len(values), values)) def _parse_transform_substr(transform_substr: str) -> np.ndarray: """ Convert a single SVG transform substring into a 3x3 matrix. A well-formed transform substring has the form `type(v1 v2 ...)`. Raises a ValueError on invalid transform syntax. """ if transform_substr.count('(') != 1: raise ValueError('Invalid SVG transform substring: {0!r}'.format(transform_substr)) type_str, value_str = transform_substr.split('(') # Any leading commas/whitespace are the separator from the preceding # transform in the list, e.g. 'translate(1), rotate(30)'. type_str = type_str.strip(', \t\n\r') tokens = value_str.replace(',', ' ').split() if not all(_NUMBER_RE.match(t) for t in tokens): raise ValueError('Invalid SVG transform substring: {0!r}'.format(transform_substr)) values = [float(t) for t in tokens] # A grammar-valid value can still overflow float, e.g. '1e999'. if not all(math.isfinite(v) for v in values): raise ValueError('Non-finite value in SVG transform substring: {0!r}'.format(transform_substr)) transform = np.identity(3) if type_str == 'matrix': _check_num_parsed_values(values, [6], transform_substr) transform[0:2, 0:3] = np.array([values[0:6:2], values[1:6:2]]) elif type_str == 'translate': _check_num_parsed_values(values, [1, 2], transform_substr) transform[0, 2] = values[0] if len(values) > 1: transform[1, 2] = values[1] elif type_str == 'scale': _check_num_parsed_values(values, [1, 2], transform_substr) x_scale = values[0] y_scale = values[1] if (len(values) > 1) else x_scale transform[0, 0] = x_scale transform[1, 1] = y_scale elif type_str == 'rotate': _check_num_parsed_values(values, [1, 3], transform_substr) angle = values[0] * np.pi / 180.0 if len(values) == 3: offset = values[1:3] else: offset = (0, 0) tf_offset = np.identity(3) tf_offset[0:2, 2:3] = np.array([[offset[0]], [offset[1]]]) tf_rotate = np.identity(3) tf_rotate[0:2, 0:2] = np.array([[np.cos(angle), -np.sin(angle)], [np.sin(angle), np.cos(angle)]]) tf_offset_neg = np.identity(3) tf_offset_neg[0:2, 2:3] = np.array([[-offset[0]], [-offset[1]]]) transform = tf_offset.dot(tf_rotate).dot(tf_offset_neg) elif type_str == 'skewX': _check_num_parsed_values(values, [1], transform_substr) transform[0, 1] = np.tan(values[0] * np.pi / 180.0) elif type_str == 'skewY': _check_num_parsed_values(values, [1], transform_substr) transform[1, 0] = np.tan(values[0] * np.pi / 180.0) else: raise ValueError('Unknown SVG transform type: {0}'.format(type_str)) return transform def parse_transform(transform_str: Optional[str], strict: bool = False) -> np.ndarray: """ Convert a valid SVG transformation string into a 3x3 matrix. If the string is empty, null, or 'none', this returns a 3x3 identity matrix. By default each invalid transform substring is skipped (i.e. contributes an identity matrix) with a warning. If `strict` is true, a ValueError is raised on invalid transform syntax instead. The warnings use the SVGSyntaxWarning category, so they can be silenced or escalated selectively, e.g. `warnings.simplefilter('error', SVGSyntaxWarning)`. """ if transform_str is None or transform_str == '': return np.identity(3) elif not isinstance(transform_str, str): raise TypeError('Must provide a string to parse') # 'none' is valid (SVG 2 / CSS transform syntax) and means no transform. if transform_str.strip() == 'none': return np.identity(3) transform_substrs = transform_str.split(')') # Anything after the last ')' (e.g. a stray 'matrix' with no # parentheses) is invalid syntax, not a transform to apply -- but a # trailing list-separator comma is harmless. trailing = transform_substrs.pop() if trailing.strip(', \t\n\r'): if strict: raise ValueError('Invalid SVG transform substring: {0!r}'.format(trailing)) warnings.warn('Skipping invalid SVG transform substring: {0!r}'.format(trailing), SVGSyntaxWarning) total_transform = np.identity(3) for substr in transform_substrs: try: total_transform = total_transform.dot(_parse_transform_substr(substr)) except ValueError as e: if strict: raise warnings.warn('Skipping invalid SVG transform substring {0!r}: {1}'.format(substr, e), SVGSyntaxWarning) return total_transform