SVG

phil/qr-code

SvgWriter draws a QrCode as a standalone SVG image.

new SvgWriter(int $quietZone = 4, string $dark = '#000000', string $light = '#ffffff', int $size = 0)
    ->write(QrCode $code, string $title = '', ?Logo $logo = null): string

The image is a light square of the code's size plus the quiet zone on each side, and one path of dark squares, a run of modules of a row for each sub-path, in units of one module: viewBox="0 0 29 29" for a version 1 code with the standard quiet zone. shape-rendering="crispEdges" keeps the edges sharp at any size.

Option	Range
`$quietZone`	0 to 16 modules; readers need 4 around a code printed on a busy background
`$dark`, `$light`	`#rrggbb`; keep a strong contrast, dark on light
`$size`	0 to 4096: the `width` and `height` written, in pixels; 0 writes none, and the image takes the size its container gives it

InvalidOption refuses any other value.

The zone of a code encoded with $logoZone is left light; a Logo given to write() is drawn over it, half a module inside its edges — see Logos. A logo for a code without a zone is refused.

Accessibility

The image carries role="img" and a <title>: the $title given, or the code's own text. Screen readers announce it; a page that shows the address beside the code may give a shorter title, such as "QR code of the ticket". The text of a Wi-Fi code holds its password: give such a code the label() of its content as title.

Safety

The only text written is the title, escaped for XML. A logo is embedded as a data: URI in an <image> element, where an SVG logo runs no script and loads nothing. The image holds no script, link, style sheet nor external reference, so it is safe to write inline in a page and to keep in a database.