line.kv

<Main>
    size: 400, 400
    canvas:
        Line:
            points: root.line1
            width: 1.0
        Rectangle:
            pos: self.pos1
            size: 30, 30

line.py

#!/usr/bin/python3
import kivy
kivy.require("1.9.0")

from kivy.app import App
from kivy.core.window import Window
from kivy.uix.widget import Widget
from kivy.vector import Vector
from kivy.clock import Clock
from kivy.properties import ListProperty, DictProperty

from path import Path
import json

class Main(Widget):
    line1= ListProperty([100, 100, 600, 500])
    pos1 = ListProperty([200, 400])
    move = DictProperty({"up":False, "down":False, "right":False, "left":False})

    def setup(self):
        self.keyboard = Window.request_keyboard(self.key_off, self)
        self.keyboard.bind(on_key_down=self.key_down)
        self.keyboard.bind(on_key_up=self.key_up)
        self.import_json("Main_walls.json")

    def key_off(self):
        pass

    def key_down(self, keyboard, keycode, text, mod):
        if keycode[1] == "w":
            self.move["up"] = True
        if keycode[1] == "s":
            self.move["down"] = True
        if keycode[1] == "d":
            self.move["right"] = True
        if keycode[1] == "a":
            self.move["left"] = True

    def key_up(self, k, keycode):
        if keycode[1] == "w":
            self.move["up"] = False
        if keycode[1] == "s":
            self.move["down"] = False
        if keycode[1] == "d":
            self.move["right"] = False
        if keycode[1] == "a":
            self.move["left"] = False

    def on_touch_down(self, touch):
        pass

    def import_json(self, filename):
        js_file = Path("./data/collision/church/{}".format(filename))
        with open(js_file, "r+") as f:
            js_dict = json.load(f)
        self.line1 = [(int(i[0]/2), int(i[1]/2)) for i in js_dict["main"]]
        print(self.line1)


    def h_l(self, n1, n2):
        """
        higher_lower. Returns the higher number first.
        """
        if n1 > n2:
            return n1, n2
        else:
            return n2, n1

    def does_it_intersect(self):
        a1 = (self.line1[0], self.line1[1])
        a2 = (self.line1[2], self.line1[3])
        b1 = (self.line2[0], self.line2[1])
        b2 = (self.line2[2], self.line2[3])
        x, y = Vector.line_intersection(a1, a2, b1, b2)
        a_xh, a_xl = self.h_l(a1[0], a2[0])
        a_yh, a_yl = self.h_l(a1[1], a2[1])
        b_xh, b_xl = self.h_l(b1[0], b2[0])
        b_yh, b_yl = self.h_l(b1[1], b2[1])
        if x < a_xh and x > a_xl and y < a_yh and y > a_yl:
            if x < b_xh and x > b_xl and y < b_yh and y > b_yl:
                return True
        return False

    def update(self, dt):
        if self.move["up"]:
            self.pos1[1] += 5
        if self.move["down"]:
            self.pos1[1] -= 5
        if self.move["right"]:
            self.pos1[0] += 5
        if self.move["left"]:
            self.pos1[0] -= 5

class LineApp(App):

    def build(self):
        game = Main()
        game.setup()
        Clock.schedule_interval(game.update, 1/60)
        return game

if __name__ == "__main__":
    app = LineApp()
    app.run()