150 lines
4.7 KiB
Python
150 lines
4.7 KiB
Python
#!/usr/bin/env python3
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import sys
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from pathlib import Path
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deps_dir = Path(__file__).parent / "deps"
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if deps_dir.exists() and str(deps_dir) not in sys.path:
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sys.path.insert(0, str(deps_dir))
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import math
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import inkex
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from inkex import PathElement, Rectangle, Transform
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def calculate_path_length(path):
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if isinstance(path, str):
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path = inkex.Path(path)
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csp = path.to_superpath()
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total_length = 0.0
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for subpath in csp:
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for i, seg in enumerate(subpath[:-1]):
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next_seg = subpath[i + 1]
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bezier = (seg[1], seg[2], next_seg[0], next_seg[1])
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seg_length = inkex.bezier.bezierlength(bezier, tolerance=0.01)
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total_length += seg_length
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return total_length
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def point_at_length(path, target_length):
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if isinstance(path, str):
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path = inkex.Path(path)
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csp = path.to_superpath()
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current_length = 0.0
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for subpath in csp:
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for i, seg in enumerate(subpath[:-1]):
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next_seg = subpath[i + 1]
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bezier = (seg[1], seg[2], next_seg[0], next_seg[1])
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seg_length = inkex.bezier.bezierlength(bezier, tolerance=0.01)
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if current_length + seg_length >= target_length:
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t = (target_length - current_length) / seg_length if seg_length > 0 else 0
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t = max(0.0, min(1.0, t))
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p0, p1, p2, p3 = bezier
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p0_p1_dist = ((p1[0] - p0[0])**2 + (p1[1] - p0[1])**2)**0.5
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p2_p3_dist = ((p3[0] - p2[0])**2 + (p3[1] - p2[1])**2)**0.5
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if p0_p1_dist < 0.001 and p2_p3_dist < 0.001:
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point = (
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p0[0] + t * (p3[0] - p0[0]),
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p0[1] + t * (p3[1] - p0[1])
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)
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else:
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point = inkex.bezier.bezierpointatt(bezier, t)
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p0, p1, p2, p3 = bezier
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one_minus_t = 1.0 - t
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dx = (3 * one_minus_t * one_minus_t * (p1[0] - p0[0]) +
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6 * one_minus_t * t * (p2[0] - p1[0]) +
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3 * t * t * (p3[0] - p2[0]))
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dy = (3 * one_minus_t * one_minus_t * (p1[1] - p0[1]) +
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6 * one_minus_t * t * (p2[1] - p1[1]) +
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3 * t * t * (p3[1] - p2[1]))
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length = (dx * dx + dy * dy) ** 0.5
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if length > 0:
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dx /= length
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dy /= length
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return (point[0], point[1]), (dx, dy)
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current_length += seg_length
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last_subpath = csp[-1]
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last_point = last_subpath[-1][1]
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return (last_point[0], last_point[1]), (1.0, 0.0)
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def pattern_along_path(path, num_items, item_width, start_offset, spacing, create_shape_fn):
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if isinstance(path, str):
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path = inkex.Path(path)
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if num_items <= 0:
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return []
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total_length = calculate_path_length(path)
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items = []
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if spacing == "even":
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gap = (total_length - num_items * item_width) / num_items
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for i in range(num_items):
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item_start = (start_offset + i * (gap + item_width)) % total_length
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item_center = (item_start + item_width / 2) % total_length
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point, tangent = point_at_length(path, item_center)
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angle = math.degrees(math.atan2(tangent[1], tangent[0]))
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item = create_shape_fn(i)
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transform = Transform()
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transform.add_translate(point[0], point[1])
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transform.add_rotate(angle)
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item.transform = transform
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items.append(item)
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elif spacing == "endpoints":
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for i in range(num_items):
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base_distance = total_length * i / (num_items - 1) if num_items > 1 else 0
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distance = (base_distance + start_offset) % total_length
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point, tangent = point_at_length(path, distance)
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angle = math.degrees(math.atan2(tangent[1], tangent[0]))
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item = create_shape_fn(i)
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transform = Transform()
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transform.add_translate(point[0], point[1])
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transform.add_rotate(angle)
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item.transform = transform
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items.append(item)
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elif spacing == "simple":
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gap = (total_length - num_items * item_width) / num_items
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for i in range(num_items):
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item_start = (start_offset + i * (gap + item_width)) % total_length
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distance = (item_start + item_width / 2) % total_length
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point, tangent = point_at_length(path, distance)
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angle = math.degrees(math.atan2(tangent[1], tangent[0]))
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item = create_shape_fn(i)
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transform = Transform()
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transform.add_translate(point[0], point[1])
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transform.add_rotate(angle)
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item.transform = transform
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items.append(item)
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return items
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