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Diffstat (limited to 'taep/svg_util.py')
| -rw-r--r-- | taep/svg_util.py | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/taep/svg_util.py b/taep/svg_util.py new file mode 100644 index 0000000..009e9a5 --- /dev/null +++ b/taep/svg_util.py @@ -0,0 +1,327 @@ +import math +import re +import textwrap +from dataclasses import dataclass + + +@dataclass(frozen=True, slots=True) +class LengthUnit: + """ Convenience length unit class. Used in :py:class:`.GraphicObject` and :py:class:`.Aperture` to store length + information. Provides a number of useful unit conversion functions. + + Singleton, use only global instances ``utils.MM`` and ``utils.Inch``. + """ + + name: str + shorthand: str + this_in_mm: float + + def convert_from(self, unit, value): + """ Convert ``value`` from ``unit`` into this unit. + + :param unit: ``MM``, ``Inch`` or one of the strings ``"mm"`` or ``"inch"`` + :param float value: + :rtype: float + """ + + if isinstance(unit, str): + unit = units[unit] + + if unit == self or unit is None or value is None: + return value + + return value * unit.this_in_mm / self.this_in_mm + + def convert_to(self, unit, value): + """ :py:meth:`.LengthUnit.convert_from` but in reverse. """ + + if isinstance(unit, str): + unit = to_unit(unit) + + if unit is None: + return value + + return unit.convert_from(self, value) + + def convert_bounds_from(self, unit, value): + """ :py:meth:`.LengthUnit.convert_from` but for ((min_x, min_y), (max_x, max_y)) bounding box tuples. """ + + if value is None: + return None + + (min_x, min_y), (max_x, max_y) = value + min_x = self.convert_from(unit, min_x) + min_y = self.convert_from(unit, min_y) + max_x = self.convert_from(unit, max_x) + max_y = self.convert_from(unit, max_y) + return (min_x, min_y), (max_x, max_y) + + def convert_bounds_to(self, unit, value): + """ :py:meth:`.LengthUnit.convert_to` but for ((min_x, min_y), (max_x, max_y)) bounding box tuples. """ + + if value is None: + return None + + (min_x, min_y), (max_x, max_y) = value + min_x = self.convert_to(unit, min_x) + min_y = self.convert_to(unit, min_y) + max_x = self.convert_to(unit, max_x) + max_y = self.convert_to(unit, max_y) + return (min_x, min_y), (max_x, max_y) + + def format(self, value): + """ Return a human-readdable string representing value in this unit. + + :param float value: + :returns: something like "3mm" + :rtype: str + """ + + return f'{value:.3f}{self.shorthand}' if value is not None else '' + + def __call__(self, value, unit): + """ Convenience alias for :py:meth:`.LengthUnit.convert_from` """ + return self.convert_from(unit, value) + + def __eq__(self, other): + if isinstance(other, str): + return other.lower() in (self.name, self.shorthand) + else: + return id(self) == id(other) + + # This class is a singleton, we don't want copies around + def __copy__(self): + return self + + def __deepcopy__(self, memo): + return self + + def __str__(self): + return self.shorthand + + def __repr__(self): + return f'<LengthUnit {self.name}>' + + +MILLIMETERS_PER_INCH = 25.4 +Inch = LengthUnit('inch', 'in', MILLIMETERS_PER_INCH) +MM = LengthUnit('millimeter', 'mm', 1) +units = {'inch': Inch, 'mm': MM, None: None} + + +class Tag: + """ Helper class to ease creation of SVG. All API functions that create SVG allow you to substitute this with your + own implementation by passing a ``tag`` parameter. """ + + def __init__(self, name, children=None, root=False, **attrs): + if (fill := attrs.get('fill')) and isinstance(fill, tuple): + attrs['fill'], attrs['fill-opacity'] = fill + if (stroke := attrs.get('stroke')) and isinstance(stroke, tuple): + attrs['stroke'], attrs['stroke-opacity'] = stroke + self.name, self.attrs = name, attrs + self.children = children or [] + self.root = root + + def __str__(self): + prefix = '<?xml version="1.0" encoding="utf-8"?>\n' if self.root else '' + opening = ' '.join([self.name] + [f'{key.replace("__", ":").replace("_", "-")}="{value}"' for key, value in self.attrs.items()]) + if self.children: + children = '\n'.join(textwrap.indent(str(c), ' ') for c in self.children) + return f'{prefix}<{opening}>\n{children}\n</{self.name}>' + else: + return f'{prefix}<{opening}/>' + + +def svg_rotation(angle_rad, cx=0, cy=0): + if math.isclose(angle_rad, 0.0, abs_tol=1e-3): + return {} + else: + return {'transform': f'rotate({float(math.degrees(angle_rad)):.4} {float(cx):.6} {float(cy):.6})'} + +def setup_svg(tags, bounds, margin=0, arg_unit=MM, svg_unit=MM, pagecolor='white', tag=Tag, inkscape=False): + (min_x, min_y), (max_x, max_y) = bounds + + if margin: + margin = svg_unit(margin, arg_unit) + min_x -= margin + min_y -= margin + max_x += margin + max_y += margin + + w, h = max_x - min_x, max_y - min_y + w = 1.0 if math.isclose(w, 0.0) else w + h = 1.0 if math.isclose(h, 0.0) else h + + if inkscape: + tags.insert(0, tag('sodipodi:namedview', [], id='namedview1', pagecolor=pagecolor, + inkscape__document_units=svg_unit.shorthand)) + namespaces = dict( + xmlns="http://www.w3.org/2000/svg", + xmlns__xlink="http://www.w3.org/1999/xlink", + xmlns__sodipodi='http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd', + xmlns__inkscape='http://www.inkscape.org/namespaces/inkscape') + + else: + namespaces = dict( + xmlns="http://www.w3.org/2000/svg", + xmlns__xlink="http://www.w3.org/1999/xlink") + + svg_unit = 'in' if svg_unit == 'inch' else 'mm' + # TODO export apertures as <uses> where reasonable. + return tag('svg', tags, + width=f'{w}{svg_unit}', height=f'{h}{svg_unit}', + viewBox=f'{min_x} {min_y} {w} {h}', + style=f'background-color:{pagecolor}', + **namespaces, + root=True) + + +class Transform: + xform_re = r'((matrix|translate|scale|rotate|skewX|skewY)\(([-0-9. ]+)\))|(.+)' + + def __init__(self, a=1, b=0, c=0, d=1, e=0, f=0): + # Reference: https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/transform + self.mat = (a, b, c, d, e, f) + + def __mul__(self, other): + a1, b1, c1, d1, e1, f1 = self.mat + a2, b2, c2, d2, e2, f2 = other.mat + + a = a1*a2 + c1*b2 + b = d1*b2 + b1*a2 + c = c1*d2 + a1*c2 + d = d1*d2 + b1*c2 + e = e1 + c1*f2 + a1*e2 + f = f1 + d1*f2 + b1*e2 + + return Transform(a, b, c, d, e, f) + + def __str__(self): + a, b, c, d, e, f = self.mat + return f'Transform({a=:.3f} {b=:.3f} {c=:.3f} {d=:.3f} {e=:.3f} {f=:.3f})' + + def transform_point(self, x, y): + a, b, c, d, e, f = self.mat + x_new = a*x + c*y + e + y_new = b*x + d*y + f + return x_new, y_new + + @classmethod + def translate(kls, x, y): + return kls(1, 0, 0, 1, x, y) + + @classmethod + def scale(kls, x, y): + return kls(x, 0, 0, y, 0, 0) + + @classmethod + def rotate(kls, a, x=0, y=0): + s, c = math.sin(a), math.cos(a) + mat = kls(c, s, -s, c, 0, 0) + if not math.isclose(x, 0) or not math.isclose(y, 0): + mat = kls.translate(x, y) * (mat * kls.translate(-x, -y)) + return mat + + @classmethod + def skew_x(kls, a): + return kls(1, 0, math.tan(a), 1, 0, 0) + + @classmethod + def skew_y(kls, a): + return kls(1, math.tan(a), 0, 1, 0, 0) + + @classmethod + def _parse_single_svg(kls, xform_string): + _transform, name, nums, _garbage = re.match(kls.xform_re, xform_string).groups() + nums = [float(x) for x in nums.strip().split()] + match (name, *nums): + case ('matrix', a, b, c, d, e, f): + return kls(a, b, c, d, e, f) + case ('translate', x): + return kls.translate(x, 0) + case ('translate', x, y): + return kls.translate(x, y) + case ('scale', s): + return kls.scale(s, s) + case ('scale', x, y): + return kls.scale(x, y) + case ('rotate', a): + return kls.rotate(math.radians(a)) + case ('rotate', a, x, y): + return kls.rotate(math.radians(a), x, y) + case ('skewX', a): + return kls.skew_x(math.radians(a)) + case ('skewY', a): + return kls.skew_y(math.radians(a)) + + @classmethod + def parse_svg(kls, xform_string): + mat = kls() + for xf in re.finditer(kls.xform_re, xform_string): + component, command, params, garbage = xf.groups() + if garbage: + raise ValueError(f'Unknown SVG transform {garbage!r}') + mat *= kls._parse_single_svg(xf.group(0)) + return mat + + def as_svg(self): + a, b, c, d, e, f = self.mat + return f'matrix({a} {b} {c} {d} {e} {f})' + + +def parse_path_d(d): + # Reference: https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/d#path_commands + cur_x, cur_y = None, None + start_x, start_y = None, None + for m in re.finditer(r'([MmLlHhVvCcSsQqTtAaZz])\s*((-?[0-9.]+)(\s*[\s,]\s*-?[0-9.]+)*)', d): + command = m.group(1) + is_relative, command = command.islower(), command.upper() + params = [float(x or 0) for x in re.split(r'\s*[\s,]\s*', m.group(2).strip())] + + def r(x, y, reset=True): + if is_relative: + x, y = x+cur_x, y+cur_y + if reset: + cur_x, cur_y = x, y + return x, y + + if command == 'Z': + if params: + raise ValueError('Z (close path) command followed by numeric parameters') + if not math.isclose(cur_x, start_x) or not math.isclose(cur_y, start_y): + yield 'L', (start_x, start_y) + + else: + while params: + match (command, *params): + case ('M', x, y, *_extra): + yield 'M', r(x, y) + start_x, start_y = cur_x, cur_y + command = 'L' + params = params[2:] + case ('L', x, y, *_extra): + yield 'L', r(x, y) + params = params[2:] + case ('H', x, *_extra): + yield 'L', r(x, 0 if is_relative else cur_y) + params = params[1:] + case ('V', y, *_extra): + yield 'L', r(0 if is_relative else cur_x, y) + params = params[1:] + case ('C', x1, y1, x2, y2, x, y, *_extra): + yield 'C', r(x1, y1, False), r(x2, y2, False), r(x, y) + params = params[6:] + case ('S', dx2, dy2, x, y, *_extra): + yield 'S', r(dx2, dy2, False), r(x, y) + params = params[4:] + case ('Q', x1, y1, x, y, *_extra): + yield 'Q', r(x1, y1, False), r(x, y) + params = params[4:] + case ('T', x, y, *_extra): + yield 'T', r(x, y) + params = params[2:] + case ('A', rx, ry, a, l, s, x, y, *_extra): + yield 'A', (rx, ry), a, l, s, r(x, y) + params = params[7:] + + |