7a0be0c812
Rewrite of the code which calculates the document scale and simplified code path which applies the necessary transformations.
243 lines
6.7 KiB
Python
243 lines
6.7 KiB
Python
"""
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Based on code from Aaron Spike. See http://www.bobcookdev.com/inkscape/inkscape-dxf.html
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"""
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import pkgutil, os, re, collections, itertools
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from . import inkex, simpletransform, cubicsuperpath, cspsubdiv, inkscape
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def _get_unit_factors_map():
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# Fluctuates somewhat between Inkscape releases _and_ between SVG version.
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pixels_per_inch = 96.
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pixels_per_mm = pixels_per_inch / 25.4
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return {
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'px': 1.0,
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'mm': pixels_per_mm,
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'cm': pixels_per_mm * 10,
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'm' : pixels_per_mm * 1e3,
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'km': pixels_per_mm * 1e6,
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'pt': pixels_per_inch / 72,
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'pc': pixels_per_inch / 6,
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'in': pixels_per_inch,
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'ft': pixels_per_inch * 12,
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'yd': pixels_per_inch * 36 }
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class ExportEffect(inkex.Effect):
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_unit_factors = _get_unit_factors_map()
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_asymptote_all_paths_name = 'all'
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def __init__(self):
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inkex.Effect.__init__(self)
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self._flatness = float(os.environ['DXF_FLATNESS'])
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self._layers = None
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self._paths = None
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def _get_document_scale(self):
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"""
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Return scaling factor applied to the document because of a viewBox setting. This currently ignores any setting of a preserveAspectRatio attribute (like Inkscape).
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"""
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document_height = self._get_height()
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view_box = self._get_view_box()
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if view_box is None or document_height is None:
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return 1
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else:
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_, _, _, view_box_height = view_box
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return document_height / view_box_height
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def _get_document_height(self):
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"""
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Get the height of the document in pixels in the document coordinate system as it is interpreted by Inkscape.
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"""
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view_box = self._get_view_box()
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document_height = self._get_height()
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if view_box is not None:
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_, _, _, view_box_height = view_box
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return view_box_height
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elif document_height is not None:
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return document_height
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else:
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return 0
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def _get_height(self):
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height_attr = self.document.getroot().get('height')
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if height_attr is None:
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return None
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else:
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return self._measure_to_pixels(height_attr)
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def _get_view_box(self):
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view_box_attr = self.document.getroot().get('viewBox')
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if view_box_attr is None:
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return None
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else:
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return [float(i) for i in view_box_attr.split()]
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def _get_shape_paths(self, node, transform):
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shape = cubicsuperpath.parsePath(node.get('d'))
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transform = simpletransform.composeTransform(
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transform,
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simpletransform.composeParents(node, [[1, 0, 0], [0, 1, 0]]))
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simpletransform.applyTransformToPath(transform, shape)
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def iter_paths():
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for path in shape:
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cspsubdiv.subdiv(path, self._flatness)
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# path contains two control point coordinates and the actual coordinates per point.
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yield [i for _, i, _ in path]
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return list(iter_paths())
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def effect(self):
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document_height = self._get_document_height()
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document_scale = self._get_document_scale()
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transform = simpletransform.composeTransform(
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[[document_scale, 0, 0], [0, document_scale, 0]],
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[[1, 0, 0], [0, -1, document_height]])
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layers = inkscape.get_inkscape_layers(self.svg_file)
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layers_by_inkscape_name = { i.inkscape_name: i for i in layers }
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def iter_paths():
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for node in self.document.getroot().xpath('//svg:path', namespaces = inkex.NSS):
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layer = layers_by_inkscape_name.get(self._get_inkscape_layer_name(node))
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for path in self._get_shape_paths(node, transform):
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yield layer, path
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self._layers = layers
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self._paths = list(iter_paths())
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def write_dxf(self, file):
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# Scales pixels to millimeters. This is the predominant unit in CAD.
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unit_factor = self._unit_factors['mm']
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layer_indices = { l: i for i, l in enumerate(self._layers) }
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file.write(pkgutil.get_data(__name__, 'dxf_header.txt'))
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def write_instruction(code, value):
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print >> file, code
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print >> file, value
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handle_iter = itertools.count(256)
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for layer, path in self._paths:
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for (x1, y1), (x2, y2) in zip(path, path[1:]):
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write_instruction(0, 'LINE')
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if layer is not None:
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write_instruction(8, layer.export_name)
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write_instruction(62, layer_indices.get(layer, 0))
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write_instruction(5, '{:x}'.format(next(handle_iter)))
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write_instruction(100, 'AcDbEntity')
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write_instruction(100, 'AcDbLine')
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write_instruction(10, repr(x1 / unit_factor))
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write_instruction(20, repr(y1 / unit_factor))
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write_instruction(30, 0.0)
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write_instruction(11, repr(x2 / unit_factor))
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write_instruction(21, repr(y2 / unit_factor))
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write_instruction(31, 0.0)
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file.write(pkgutil.get_data(__name__, 'dxf_footer.txt'))
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def write_asy(self, file):
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def write_line(format, *args):
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print >> file, format.format(*args) + ';'
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# Scales pixels to points. Asymptote uses points by default.
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unit_factor = self._unit_factors['pt']
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paths_by_layer = collections.defaultdict(list)
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variable_names = []
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for layer, path in self._paths:
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paths_by_layer[layer].append(path)
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for layer in self._layers + [None]:
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paths = paths_by_layer[layer]
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variable_name = self._asymptote_identifier_from_layer(layer)
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write_line('path[] {}', variable_name)
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variable_names.append(variable_name)
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for path in paths:
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point_strs = ['({}, {})'.format(x / unit_factor, y / unit_factor) for x, y in path]
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# Hack. We should determine this from whether Z or z was used to close the path in the SVG document.
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if path[0] == path[-1]:
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point_strs[-1] = 'cycle'
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write_line('{}.push({})', variable_name, ' -- '.join(point_strs))
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if self._asymptote_all_paths_name not in variable_names:
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write_line('path[] {}', self._asymptote_all_paths_name)
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for i in variable_names:
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write_line('{}.append({})', self._asymptote_all_paths_name, i)
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@classmethod
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def _parse_measure(cls, string):
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value_match = re.match(r'(([-+]?[0-9]+(\.[0-9]*)?|[-+]?\.[0-9]+)([eE][-+]?[0-9]+)?)', string)
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unit_match = re.search('(%s)$' % '|'.join(cls._unit_factors.keys()), string)
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value = float(string[value_match.start():value_match.end()])
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if unit_match:
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unit = string[unit_match.start():unit_match.end()]
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else:
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unit = None
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return value, unit
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@classmethod
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def _measure_to_pixels(cls, string):
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"""
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Parse a string containing a measure and return it's value converted to pixels.
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"""
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value, unit = cls._parse_measure(string)
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return value * cls._get_unit_factor(unit)
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@classmethod
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def _get_inkscape_layer_name(cls, node):
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while node is not None:
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layer = node.get(inkex.addNS('label', 'inkscape'))
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if layer is not None:
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return layer
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node = node.getparent()
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return None
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@classmethod
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def _get_unit_factor(cls, unit):
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if unit is None:
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return 1
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else:
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return cls._unit_factors[unit]
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@classmethod
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def _asymptote_identifier_from_layer(cls, layer):
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if layer is None:
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return '_'
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else:
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return re.sub('[^a-zA-Z0-9]', '_', layer.export_name)
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