cutandshift.py

""" implementing a brainstormed cut-and-shift operation on polygons
    working from code snagged from Gary Whitehead in masto conversation:
    https://mastodon.social/@grwster/109734946667028881
"""
from cortexdraw import *

circles = []
patches = []

squaresize = 2

width = squaresize * 2
height = squaresize * 2

def op2(m):
    tophalf = int(height/2)
    bottomhalf = height
    for i in range(tophalf):
        m[i].insert(0, 0)
        m[i].pop()
    for i in range(tophalf + 1, bottomhalf):
        m[i].append(0)
        m[i].pop(0)


def op1(m):
    for i in range(11):
        newgrid = [[row[i] for row in m] for i in range(width)]
        op2(newgrid)
        m = [[row[i] for row in newgrid] for i in range(width)]

# construct a 2D array of zero values and stock it with square shape number values
# in the center
# - NOTE: squaresize is expected to be a multiple of 2!


def makearray(squaresize):

    gsize = squaresize * 2
    grid = []
    # create an array of zeros big enough to allow space to shift the square's bits around
    for i in range(gsize):
        newl = []
        for j in range(gsize):
            newl.append(0)
        grid.append(newl)

    # and then add squares digits to the center
    dxy = int(squaresize/2)
    for i in range(1, squaresize*squaresize + 1):
        grid[i % squaresize + dxy][int(i/squaresize)] = i

    return grid


def newpatch(dx, dy):
    offx = dx * width + 1
    offy = dy * height + 1
    for x in range(len(m)):
        for y in range(len(m[x])):
            r = 1
            if m[x][y] > 0:
                # r = 0.1
                circles.append(([x+offx, y+offy], r))

    for c, r in circles:   
        ax.add_patch(mpatches.Arc(c, r, r, color=[0, 0, 0]))


m = makearray(squaresize)
print(m)

fig, ax = plt.subplots(figsize=(10, 10), frameon=False)

newpatch(0, 0)
for i in range(1, 6, 2):
    op1(m)
    print(m)
    newpatch(i, 0)
    op2(m)
    newpatch(i+1, 0)

# for i in range(6):
#     newpatch(i,0)

plt.grid(False)
plt.axis('off')
ax.set_aspect('equal')

x_bounds = [-1, width * 6 + 1]
y_bounds = [-1, height * 1 + 1]

ax.set_xlim(x_bounds)
ax.set_ylim(y_bounds)

collection = PatchCollection(patches, match_original=True)
ax.add_collection(collection)

plt.savefig('cutandshift.svg', bbox_inches='tight', pad_inches=0)
plt.show()

vpypeout(['cutandshift.svg'])