kopia lustrzana https://github.com/inkstitch/inkstitch
120 wiersze
4.5 KiB
Python
120 wiersze
4.5 KiB
Python
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import inkex
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from shapely import geometry as shgeo
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from itertools import chain
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from .base import InkstitchExtension
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from ..svg.tags import SVG_PATH_TAG
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from ..svg import get_correction_transform, PIXELS_PER_MM
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from ..elements import Stroke
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from ..utils import Point
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class ConvertToSatin(InkstitchExtension):
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"""Convert a line to a satin column of the same width."""
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def effect(self):
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if not self.get_elements():
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return
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if not self.selected:
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inkex.errormsg(_("Please select at least one line to convert to a satin column."))
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return
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if not all(isinstance(item, Stroke) for item in self.elements):
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# L10N: Convert To Satin extension, user selected one or more objects that were not lines.
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inkex.errormsg(_("Only simple lines may be converted to satin columns."))
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return
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for element in self.elements:
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parent = element.node.getparent()
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index = parent.index(element.node)
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correction_transform = get_correction_transform(element.node)
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for path in element.paths:
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try:
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rails, rungs = self.path_to_satin(path, element.stroke_width)
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except ValueError:
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inkex.errormsg(_("Cannot convert %s to a satin column because it intersects itself. Try breaking it up into multiple paths.") % element.node.get('id'))
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parent.insert(index, self.satin_to_svg_node(rails, rungs, correction_transform))
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parent.remove(element.node)
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def path_to_satin(self, path, stroke_width):
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path = shgeo.LineString(path)
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left_rail = path.parallel_offset(stroke_width / 2.0, 'left')
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right_rail = path.parallel_offset(stroke_width / 2.0, 'right')
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if not isinstance(left_rail, shgeo.LineString) or \
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not isinstance(right_rail, shgeo.LineString):
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# If the parallel offsets come out as anything but a LineString, that means the
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# path intersects itself, when taking its stroke width into consideration. See
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# the last example for parallel_offset() in the Shapely documentation:
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# https://shapely.readthedocs.io/en/latest/manual.html#object.parallel_offset
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raise ValueError()
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# for whatever reason, shapely returns a right-side offset's coordinates in reverse
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left_rail = list(left_rail.coords)
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right_rail = list(reversed(right_rail.coords))
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rungs = self.generate_rungs(path, stroke_width)
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return (left_rail, right_rail), rungs
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def generate_rungs(self, path, stroke_width):
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rungs = []
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# approximately 1cm between rungs, and we don't want them at the very start or end
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num_rungs = int(path.length / PIXELS_PER_MM / 10) - 1
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if num_rungs < 1 or num_rungs == 2:
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# avoid 2 rungs because it can be ambiguous (which are the rails and which are the
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# rungs?)
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num_rungs += 1
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distance_between_rungs = path.length / (num_rungs + 1)
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for i in xrange(num_rungs):
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rung_center = path.interpolate((i + 1) * distance_between_rungs)
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rung_center = Point(rung_center.x, rung_center.y)
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# TODO: use bezierslopeatt or whatever
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# we need to calculate the normal at this point so grab another point just a little
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# further down the path, effectively grabbing a small segment of the path
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segment_end = path.interpolate((i + 1) * distance_between_rungs + 0.1)
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segment_end = Point(segment_end.x, segment_end.y)
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tangent = segment_end - rung_center
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normal = tangent.unit().rotate_left()
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offset = normal * stroke_width * 0.75
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rung_start = rung_center + offset
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rung_end = rung_center - offset
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rungs.append((rung_start.as_tuple(), rung_end.as_tuple()))
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return rungs
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import sys
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print >> sys.stderr, rails, rungs
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def satin_to_svg_node(self, rails, rungs, correction_transform):
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d = ""
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for path in chain(rails, rungs):
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d += "M"
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for x, y in path:
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d += "%s,%s " % (x, y)
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d += " "
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return inkex.etree.Element(SVG_PATH_TAG,
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{
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"id": self.uniqueId("path"),
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"style": "stroke:#000000;stroke-width:1px;fill:none",
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"transform": correction_transform,
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"d": d,
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"embroider_satin_column": "true",
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}
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)
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