This implementation is using the bit matrix returned by zxing,
and then we do our own SVG rendering.
The SIX-supplied Swiss Cross SVG version is now used for the overlay.
The resulting SVG has been successfully tested in a number of different SVG
rendering engines:
• Google Chrome 86
• Firefox 82
• Emacs 26
• GIMP
• Inkscape
• Mobile Safari
When rendering the SVG onto 1265x1265 px at 600 dpi,
the resulting image matches the PNG version exactly.
