From b15029a07eef79aec69d6bf1714fd54560b957bd Mon Sep 17 00:00:00 2001
From: Sergey Vartanov <me@enzet.ru>
Date: Tue, 1 Jun 2021 04:15:29 +0300
Subject: [PATCH] Issue #45: fix line intersection.

Use infinite lines to find intersection point.
---
 roentgen/road.py   | 34 ++++++++++++++--------------------
 roentgen/vector.py | 12 +++++++-----
 2 files changed, 21 insertions(+), 25 deletions(-)

diff --git a/roentgen/road.py b/roentgen/road.py
index 1573a58..c578190 100644
--- a/roentgen/road.py
+++ b/roentgen/road.py
@@ -6,11 +6,10 @@ from typing import List
 
 import numpy as np
 import svgwrite
-from shapely.geometry import LineString, Point
 
 from roentgen.constructor import Road
 from roentgen.flinger import Flinger
-from roentgen.vector import angle, turn_by_angle, norm
+from roentgen.vector import angle, turn_by_angle, norm, Line
 from roentgen.osm_reader import OSMNode
 
 
@@ -163,7 +162,7 @@ class RoadPart:
         ]
         drawing.add(drawing.path(path_commands, fill="#CCCCCC"))
 
-        self.draw_entrance(drawing, False)
+        # self.draw_entrance(drawing, False)
 
     def draw_entrance(self, drawing: svgwrite.Drawing, is_debug: bool):
         path_commands = [
@@ -210,26 +209,21 @@ class Intersection:
             next_index: int = 0 if index == len(self.parts) - 1 else index + 1
             part_1 = self.parts[index]
             part_2 = self.parts[next_index]
-            line_1 = LineString(
-                [
-                    part_1.point_1 + part_1.right_vector,
-                    part_1.point_2 + part_1.right_vector,
-                ]
+            line_1 = Line(
+                part_1.point_1 + part_1.right_vector,
+                part_1.point_2 + part_1.right_vector,
             )
-            line_2 = LineString(
-                [
-                    part_2.point_1 + part_2.left_vector,
-                    part_2.point_2 + part_2.left_vector,
-                ]
+            line_2 = Line(
+                part_2.point_1 + part_2.left_vector,
+                part_2.point_2 + part_2.left_vector,
             )
-            a = line_1.intersection(line_2)
-            if isinstance(a, Point):
-                part_1.right_connection = np.array((a.x, a.y))
-                part_2.left_connection = np.array((a.x, a.y))
-                part_1.update()
-                part_2.update()
+            a = line_1.get_intersection_point(line_2)
+            part_1.right_connection = a
+            part_2.left_connection = a
+            part_1.update()
+            part_2.update()
 
-    def draw(self, drawing: svgwrite.Drawing, is_debug: bool):
+    def draw(self, drawing: svgwrite.Drawing, is_debug: bool = False):
         """
         Draw all road parts and intersection.
         """
diff --git a/roentgen/vector.py b/roentgen/vector.py
index fd48815..bfa00ce 100644
--- a/roentgen/vector.py
+++ b/roentgen/vector.py
@@ -21,10 +21,12 @@ def turn_by_angle(vector: np.array, angle: float):
     """
     Turn vector by an angle.
     """
-    return np.array((
-        vector[0] * np.cos(angle) - vector[1] * np.sin(angle),
-        vector[0] * np.sin(angle) + vector[1] * np.cos(angle),
-    ))
+    return np.array(
+        (
+            vector[0] * np.cos(angle) - vector[1] * np.sin(angle),
+            vector[0] * np.sin(angle) + vector[1] * np.cos(angle),
+        )
+    )
 
 
 def norm(vector: np.array) -> np.array:
@@ -44,7 +46,7 @@ class Line:
         #     util.error("cannot create line by one point")
         self.a: float = start[1] - end[1]
         self.b: float = end[0] - start[0]
-        self.c: float = start.x * end.y - end.x * start.y
+        self.c: float = start[0] * end[1] - end[0] * start[1]
 
     def parallel_shift(self, shift: np.array):
         """