From c23d0f867d5acabd9c0f5bd80cefe254c2410295 Mon Sep 17 00:00:00 2001
From: MaNyh <nyhuis@tfd.uni-hannover.de>
Date: Sun, 12 Dec 2021 20:54:20 +0100
Subject: [PATCH] implement line_intersection
---
ntrfc/utils/math/vectorcalc.py | 19 ++++++++++++++++++-
tests/test_ntrfc_math.py | 9 +++++++++
2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/ntrfc/utils/math/vectorcalc.py b/ntrfc/utils/math/vectorcalc.py
index aa656013..48a7e2a1 100644
--- a/ntrfc/utils/math/vectorcalc.py
+++ b/ntrfc/utils/math/vectorcalc.py
@@ -11,7 +11,7 @@ from scipy.spatial.distance import squareform, pdist
import sys
import math as m
-import scipy
+
def calc_largedistant_idx(x_koords, y_koords):
"""
@@ -231,3 +231,20 @@ def lineseg_dist(p, a, b):
return np.hypot(h, np.linalg.norm(c))
+def line_intersection(point_a1, point_a2,
+ point_b1, point_b2):
+ def det_2d(a, b):
+ return a[0] * b[1] - a[1] * b[0]
+
+ xdiff = (point_a1[0] - point_a2[0], point_b1[0] - point_b2[0])
+ ydiff = (point_a1[1] - point_a2[1], point_b1[1] - point_b2[1])
+
+ div = det_2d(xdiff, ydiff)
+ if div == 0:
+ return None
+
+ d = (det_2d(point_a1, point_a2), det_2d(point_b1, point_b2))
+ x = det_2d(d, xdiff) / div
+ y = det_2d(d, ydiff) / div
+ return x, y
+
diff --git a/tests/test_ntrfc_math.py b/tests/test_ntrfc_math.py
index 23b1043e..ae0688fd 100644
--- a/tests/test_ntrfc_math.py
+++ b/tests/test_ntrfc_math.py
@@ -166,3 +166,12 @@ def test_vecAngle():
b = np.array([0, 1, 0])
angle = vecAngle(a, b)
assert angle == np.pi / 2
+
+
+def test_line_intersection():
+ import numpy as np
+ from ntrfc.utils.math.vectorcalc import line_intersection
+
+ intersect = line_intersection((-1,0),(1,0),
+ (0,-1),(0,1))
+ assert all(intersect==np.array([0,0]))
--
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