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| -rw-r--r-- | geometry.py | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/geometry.py b/geometry.py new file mode 100644 index 0000000..d69add8 --- /dev/null +++ b/geometry.py @@ -0,0 +1,27 @@ +import math +def distance_point_line(p, l1, l2): + # (x - l1.x) * (l2.y-l1.y)/(l2.x-l1.x) + l1.y = y + # x * (l2.y-l1.y)/(l2.x-l1.x) - l1.x * (l2.y-l1.y)/(l2.x-l1.x) + l1.y - y = 0 + # x * (l2.y-l1.y) - l1.x * (l2.y-l1.y) + l1.y * (l2.x-l1.x) - y * (l2.x-l1.x) = 0 + # ax + by + c = 0 + # with a = (l2.y-l1.y), b = -(l2.x-l1.x), c = l1.y * (l2.x-l1.x) - l1.x * (l2.y-l1.y) + a = (l2.y-l1.y) + b = -(l2.x-l1.x) + c = l1.y * (l2.x-l1.x) - l1.x * (l2.y-l1.y) + + d = math.sqrt(a**2 + b**2) + a/=d + b/=d + c/=d + + assert (abs(a*l1.x + b*l1.y + c) < 0.001) + assert (abs(a*l2.x + b*l2.y + c) < 0.001) + + return abs(a*p.x + b*p.y + c) + +def is_colinear(points, epsilon=1): + for point in points: + if distance_point_line(point, points[0], points[-1]) > epsilon: + return False + return True + |