What

Adds a new image factory qrcode.image.pdf.PdfImage that renders the QR code as a PDF document, written from scratch with no third-party dependency. The factory is also registered as the pdf shortcut for the qr console script:

qr --factory pdf --output code.pdf 'some data'

import qrcode
import qrcode.image.pdf

img = qrcode.make('some data', image_factory=qrcode.image.pdf.PdfImage)
img.save('code.pdf')

Why

PDF is a common target for print workflows (labels, invoices, tickets). A QR code only needs filled rectangles, so a minimal hand-written PDF avoids pulling in a heavyweight dependency like reportlab.

Design notes

• Single-page PDF 1.1 with one content stream of filled re rectangles; stream /Length and xref offsets are computed from the actual content.
• Horizontal runs of dark modules are merged into single rectangles to keep files small (roughly half the size of one-rect-per-module).
• PDF's coordinate system starts at the bottom-left, so rows are flipped vertically to produce the correct (non-mirrored) orientation.
• A box_size of 10 (default) renders each module at 10pt (10/72 inch).
• save() accepts a binary stream or a str/Path, matching the other factories.

Testing

• Unit tests cover the PDF structure (stream length, xref offsets pointing at the right objects), kind checking, saving to a path, and a geometry roundtrip: the rectangles from the content stream are parsed back into a module matrix and compared against QRCode.get_matrix(), which also locks in the correct orientation.
• Manually verified end-to-end: rasterized with pdftoppm and Ghostscript, decoded with zbarimg, and confirmed pixel-identical to the PIL factory's rendering of the same code.