def add_line(self, cord_1, cord_2, color):
key = tuple(sorted([tuple(cord_1), tuple(cord_2)]))
x = min(cord_1[0], cord_2[0])
y = min(cord_1[1], cord_2[1])
if key in self.lines:
print("ERROR: Line between {} and {} already added.".format(
cord_1, cord_2))
else:
line = QLabel(self)
if color == "white":
pixmap = QPixmap(get_asset_path("hor_line_white"))
else:
pixmap = QPixmap(get_asset_path("hor_line_black"))
c1 = (30 + cord_1[0] * 30, 30 + cord_1[1] * 30)
c2 = (30 + cord_2[0] * 30, 30 + cord_2[1] * 30)
length = ((c1[0] - c2[0])**2 + (c1[1] - c2[1])**2)**(1 / 2)
angle = math.degrees(
math.atan2(key[1][1] - key[0][1], key[1][0] - key[0][0]))
pixmap = pixmap.scaled(length, 5)
pixmap = pixmap.transformed(QTransform().rotate(angle))
line.setPixmap(pixmap)
line.move(30 + x * 30, 30 + y * 30)
line.show()
line.lower()
self.lines[key] = line
