Use SVG as mask to change puzzle shape

[thelabcat]

We should set the puzzle's aspect ratio from the SVG right at the start, not leave a bunch of blank to be cropped off.

[thelabcat]

import io
import cairosvg
with open("demo.svg", "rb") as f:
    data = f.read()
    
png_data_w = cairosvg.svg2png(data, output_width=100)
png_data_h = cairosvg.svg2png(data, output_height=100)
from PIL import Image
img_w = Image.open(io.BytesIO(png_data_w))
img_h = Image.open(io.BytesIO(png_data_h))

The image produced from an arbitrary black shape on a null background has anti-aliasing in this case.