gistfile1.py

        for line in norm_lines:
            a = np.cos(line[1])
            b = np.sin(line[1])        
            x0 = a*line[0]
            y0 = b*line[0]
            #print(a, b)
            #print(line[1]*180/np.pi)
            #line_func = lambda t: (x0 + b*t, y0 - a*t)
            #norm_line_seg = np.hstack([line_func(segment_length), line_func(-1*segment_length)])
            norm_line_seg = [x0 - segment_length*b,
                             y0 + segment_length*a,
                             x0 + segment_length*b,
                             y0 - segment_length*a]
            norm_line_segs.append(norm_line_seg)