import numpy as np
import matplotlib.pyplot as plt

def getSquareY(x):
    if x==-1 or x == 1:
        return 0
    else:
        return 1

getSquareYVectorised = np.vectorize(getSquareY)

def getCircle(x):
    return np.sqrt(1-np.square(x))

def transform(x,y,t):
    points = np.array([x,y])
    result = t @ points
    return result[0,:], result[1,:]

def plotGridLines(xlim,ylim,t):
    for i in range(xlim[0]-20,xlim[1]+21):
        x = [i,i]
        y = [ylim[0]-20,ylim[1]+20]
        x,y = transform(x,y,t)
        plt.plot(x,y, color='#DAD5D4',linestyle='dashed',linewidth=0.5)
    for i in range(ylim[0]-20,ylim[1]+21):
        y = [i,i]
        x = [xlim[0]-20,xlim[1]+20]
        x,y = transform(x,y,t)
        plt.plot(x,y, color='#DAD5D4',linestyle='dashed',linewidth=0.5)