fill function

def fill(n): #n - count of points
    global smooth
    global height
    global width
    clear()

    print("FILL")

    color = [1.0, 1.0, 1.0]
    global points

    #step1 - outline rasterization

    for i in range(n):
        k = (i + n - 1) % n
        j = (i + 1) % n
        x1 = points[i][0]
        y1 = points[i][1]
        x2 = points[j][0]
        y2 = points[j][1]

        ex = (y1 >= y2) ^ (y1 <= points[k][1])

        dx = abs(x2 - x1)
        dy = abs(y2 - y1)

        sx = sign(x2 - x1)
        sy = sign(y2 - y1)

        er = dx - dy

        back = [0.0, 0.0, 0.0]
        tooglePixel(x2, y2, color, back)

        if not ex:
            tooglePixel(x1, y1, color, back)

        while x1 != x2 or y1 != y2:
            er2 = er * 2
            if er2 > -dy:
                er -= dy
                x1 += sx
            if er2 < dx:
                er += dx
                y1 += sy
                tooglePixel(x1, y1, color, back)

    #step2 - filling shape

    for j in range(height):
        flag = False
        for i in range(width):
            if getPixel(i, j) == color:
                flag = not flag
            if flag:
                setPixel(i, j, color)

    #step3 - drawing outline

    drawShape(smooth)