kopia lustrzana https://github.com/inkstitch/inkstitch
67 wiersze
2.3 KiB
Python
67 wiersze
2.3 KiB
Python
""" Utility functions to produce running stitches. """
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def running_stitch(points, stitch_length):
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"""Generate running stitch along a path.
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Given a path and a stitch length, walk along the path in increments of the
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stitch length. If sharp corners are encountered, an extra stitch will be
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added at the corner to avoid rounding the corner. The starting and ending
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point are always stitched.
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The path is described by a set of line segments, each connected to the next.
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The line segments are described by a sequence of points.
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"""
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if len(points) < 2:
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return []
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output = []
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segment_start = points[0]
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last_segment_direction = None
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# This tracks the distance we've travelled along the current segment so
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# far. Each time we make a stitch, we add the stitch_length to this
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# value. If we fall off the end of the current segment, we carry over
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# the remainder to the next segment.
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distance = 0.0
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for segment_end in points[1:]:
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segment = segment_end - segment_start
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segment_length = segment.length()
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if segment_length == 0:
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continue
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segment_direction = segment.unit()
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# corner detection
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if last_segment_direction:
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cos_angle_between = segment_direction * last_segment_direction
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# This checks whether the corner is sharper than 45 degrees.
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if cos_angle_between < 0.5:
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# Only add the corner point if it's more than 0.1mm away to
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# avoid a double-stitch.
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if (segment_start - output[-1]).length() > 0.1:
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# add a stitch at the corner
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output.append(segment_start)
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# next stitch needs to be stitch_length along this segment
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distance = stitch_length
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while distance < segment_length:
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output.append(segment_start + distance * segment_direction)
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distance += stitch_length
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# prepare for the next segment
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segment_start = segment_end
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last_segment_direction = segment_direction
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distance -= segment_length
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# stitch the last point unless we're already almost there
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if (segment_start - output[-1]).length() > 0.1:
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output.append(segment_start)
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return output
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