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authorFlorian Jung <flo@windfisch.org>2015-09-01 20:47:11 +0200
committerFlorian Jung <flo@windfisch.org>2015-09-01 20:48:03 +0200
commit7a836f4a0a68188a1486b669c4cd437b5f592a5d (patch)
tree666d7867967e8d6fdc04aca6b18d8a95a077f33c /geometry.py
parentf99e10cff97afdc3e6ef07db22cf5f7fd442e067 (diff)
parent7c1180a7b58e7b8c17c8dab297058d0c001386c6 (diff)
Merge branch 'master' into pathfinding
Diffstat (limited to 'geometry.py')
-rw-r--r--geometry.py27
1 files changed, 27 insertions, 0 deletions
diff --git a/geometry.py b/geometry.py
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+++ b/geometry.py
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+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
+