How to generate full-page QR code from command line?

I'd like to generate a full-page QR code from the command line. The following command sort of accomplishes this: qrencode -o- https://example.net | convert png:- -gravity center -units pixelsperinch -density 300 -resize 2551x3295 -extent 2551x3295 qrcode.pdf Unfortunately, the resulting QR code is quite blurry, as though imagemagick is doing some sort of unwanted antialiasing. Is there a way to make the code completely crisp, or just a better/simpler approach to generating a PDF file with a full-page QR code?