kopia lustrzana https://github.com/villares/sketch-a-day
157 wiersze
4.6 KiB
Python
157 wiersze
4.6 KiB
Python
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def intersecting(poly_points):
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ed = edges(poly_points)
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intersect = False
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for p1, p2 in ed[::-1]:
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for p3, p4 in ed[2::]:
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# test only non consecutive edges
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if (p1 != p3) and (p2 != p3) and (p1 != p4):
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if line_instersect(Line(p1, p2), Line(p3, p4)):
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intersect = True
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break
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return intersect
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def is_inside(x, y, poly_points):
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min_, max_ = min_max(poly_points)
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if x < min_.x or y < min_.y or x > max_.x or y > max_.y:
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return False
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a = PVector(x, min_.y)
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b = PVector(x, max_.y)
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v_lines = inter_lines(Line(a, b), poly_points)
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if not v_lines:
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return False
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a = PVector(min_.x, y)
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b = PVector(max_.x, y)
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h_lines = inter_lines(Line(a, b), poly_points)
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if not h_lines:
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return False
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for v in v_lines:
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for h in h_lines:
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if line_instersect(v, h):
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return True
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return False
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def inter_lines(L, poly_points):
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inter_points = []
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for p1, p2 in edges(poly_points):
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inter = line_instersect(Line(p1, p2), L)
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if inter:
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inter_points.append(inter)
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if not inter_points:
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return []
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inter_lines = []
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if len(inter_points) > 1:
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inter_points.sort()
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pairs = zip(inter_points[::2], inter_points[1::2])
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for p1, p2 in pairs:
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if p2:
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inter_lines.append(Line(PVector(p1.x, p1.y),
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PVector(p2.x, p2.y)))
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return inter_lines
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class Line():
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""" I should change this to a named tuple... """
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def __init__(self, p1, p2):
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self.p1 = PVector(*p1)
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self.p2 = PVector(*p2)
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def __getitem__(self, i):
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return (self.p1, self.p2)[i]
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def plot(self):
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line(self.p1.x, self.p1.y, self.p2.x, self.p2.y)
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def lerp(self, other, t):
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p1 = PVector.lerp(self.p1, other.p1, t)
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p2 = PVector.lerp(self.p2, other.p2, t)
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return Line(p1, p2)
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def line_instersect(line_a, line_b):
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"""
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code adapted from Bernardo Fontes
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https://github.com/berinhard/sketches/
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"""
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x1, y1 = line_a.p1.x, line_a.p1.y
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x2, y2 = line_a.p2.x, line_a.p2.y
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x3, y3 = line_b.p1.x, line_b.p1.y
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x4, y4 = line_b.p2.x, line_b.p2.y
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try:
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uA = ((x4-x3)*(y1-y3) - (y4-y3)*(x1-x3)) / ((y4-y3)*(x2-x1) - (x4-x3)*(y2-y1));
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uB = ((x2-x1)*(y1-y3) - (y2-y1)*(x1-x3)) / ((y4-y3)*(x2-x1) - (x4-x3)*(y2-y1));
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except ZeroDivisionError:
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return
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if not(0 <= uA <= 1 and 0 <= uB <= 1):
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return
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x = line_a.p1.x + uA * (line_a.p2.x - line_a.p1.x)
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y = line_a.p1.y + uA * (line_a.p2.y - line_a.p1.y)
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return PVector(x, y)
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# """
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# code adapted from
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# https://stackoverflow.com/questions/27745972/test-if-polylines-intersects-using-python
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# """
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# xdiff = (line1[0][0] - line1[1][0], line2[0][0] - line2[1][0])
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# ydiff = (line1[0][1] - line1[1][1], line2[0][1] - line2[1][1])
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# def det(a, b):
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# return a[0] * b[1] - a[1] * b[0]
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# div = det(xdiff, ydiff)
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# if div == 0:
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# return None
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# d = (det(*line1), det(*line2))
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# x = det(d, xdiff) / div
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# y = det(d, ydiff) / div
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# return x, y
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# return PVector(x, y)
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def edges(poly_points):
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return pairwise(poly_points) + [(poly_points[-1], poly_points[0])]
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def pairwise(iterable):
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import itertools
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"s -> (s0,s1), (s1,s2), (s2, s3), ..."
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a, b = itertools.tee(iterable)
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next(b, None)
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return zip(a, b)
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def min_max(points):
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points = iter(points)
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try:
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p = points.next()
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min_x, min_y = max_x, max_y = p.x, p.y
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except StopIteration:
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raise ValueError, "min_max requires at least one point"
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for p in points:
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if p.x < min_x:
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min_x = p.x
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elif p.x > max_x:
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max_x = p.x
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if p.y < min_y:
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min_y = p.y
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elif p.y > max_y:
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max_y = p.y
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return (PVector(min_x, min_y),
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PVector(max_x, max_y))
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def par_hatch(points, divisions, *sides):
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vectors = [PVector(p.x, p.y) for p in points]
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lines = []
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if not sides: sides = [0]
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for s in sides:
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a, b = vectors[-1 + s], vectors[+0 + s]
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d, c = vectors[-2 + s], vectors[-3 + s]
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for i in range(1, divisions):
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s0 = PVector.lerp(a, b, i/float(divisions))
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s1 = PVector.lerp(d, c, i/float(divisions))
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lines.append(Line(s0, s1))
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return lines
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