import numpy as np
import csv
import matplotlib.pyplot as plt

def import_csv_data(filename):
    stylus_x = []
    stylus_y = []
    stylus_pressure = []
    time = []
    with open(filename) as csv_fp:
        reader = csv.reader(csv_fp)
        next(reader) # skip header
        for row in reader:
            for i, v in enumerate([stylus_x, stylus_y, stylus_pressure, time]):
                v.append(float(row[i]))
    stylus_pos = np.array([stylus_x, stylus_y])
    time = np.array(time)
    return time, stylus_pos