Three core pages and four plugin pages each imported qrcode and jsbarcode
directly, and each carried its own answer to the same questions: what margin,
what width, which error correction, how big a module must be before a scanner
can read it. The answers had already drifted - margin 0 in one place and 2 in
another, width 150 against 160 - and on a label that is the difference between
a sticker that scans and one that does not.
frontend/src/utils/codes.js owns it now: the label-stock presets, the quiet-zone
and margin defaults, CODE128 with no printed value, and the printer-resolution
arithmetic that only the Tech Tools generator had. A view passes what is
specific to its own label and nothing else - MachineBadge still asks for CODE39,
because the badge readers predate the shop-floor scanners and decode nothing
else, and that is exactly the kind of thing a call site should say out loud.
views/print/qrLogo.js is folded in rather than left as a second half-shared
helper that only some of the pages reached into.
The check script now fails a build that imports either library outside that
module. Without it this re-forks within a month: the next label page starts by
copying the nearest existing one, which is how it happened the first time.
Tests cover the part no amount of looking at a screen verifies - a QR that
looks fine at 96 dpi on a monitor can be unreadable at 203 dpi on half-inch
stock.
A place for the small utilities a technician reaches for at a bench. The
plugin owns no API and no tables: every tool runs entirely in the browser,
so an air-gapped site gets them for free and a bad network cannot break
them. Adding the next tool is a view, a route, and one entry in tools.js.
First tool is a barcode/QR generator. Content is typed text, a URL, or a
CSV (content,label,copies - quoted fields and an optional header both
handled), so a batch of a few hundred is one paste. Label stock is
adjustable in inches with five presets, and the code renders to an SVG
data URI rather than a PNG: a bitmap gets downscaled to label size and
smears the module edges a scanner reads, where SVG rasterizes at the
printer's resolution with hard edges.
It also carries the dot-grid rule that is easy to get wrong by eye. A
thermal head cannot render a fraction of a dot, so a code sized off the
grid gets uneven modules; pick a DPI and the page says what the current
size lands on and what to use instead. The quiet zone is blank label
rather than white baked into the code, so it can be tuned - and it applies
to CODE128 too, which needs clear space at each end and was letting bars
run into the caption.
Tech Tools is the first bundled plugin that owns no schema, which two
guards did not model: it belongs in the universal installer profile, and
upgrade-all reports it 'no-migrations' where every plugin was assumed to
report 'ok'. The migration test now asserts that status explicitly for
schema-less plugins, so a table-owning plugin whose chain went missing
still fails.
