def get_normal_points(cx, cy, cos_t, sin_t, length):
if length == <NUM_LIT:0.>:<EOL><INDENT>return cx, cy, cx, cy<EOL><DEDENT>cos_t1, sin_t1 = sin_t, -cos_t<EOL>cos_t2, sin_t2 = -sin_t, cos_t<EOL>x1, y1 = length*cos_t1 + cx, length*sin_t1 + cy<EOL>x2, y2 = length*cos_t2 + cx, length*sin_t2 + cy<EOL>return x1, y1, x2, y2<EOL>
For a line passing through (*cx*, *cy*) and having a angle *t*,
return locations of the two points located along its perpendicular line at the distance of *length*.