Reported as a barcode rendering 176 by 0. A bar height of zero is what does it:
the number went straight into a CSS length, height: 0in is perfectly valid, and
an image sized height: 100% of a zero-height box is zero pixels tall. The label
comes out full width with nothing on it, which reads as a rendering failure
rather than as a field doing exactly what it was told.
A cleared field was the same bug wearing a different hat. An emptied number
input holds '', not 0, so the page emitted `NaNin`; the browser dropped the
declaration and the box fell back to auto height. That one merely looked wrong
instead of vanishing, which is arguably worse for finding it.
Measurements now go through labelVars(), which will not emit NaN, an empty
length, or a zero for anything whose zero means the box stops existing. Padding,
the quiet zone and the gap still take zero, because there zero is a real answer,
and offsets stay signed. It is a separate module because this is exactly the
kind of arithmetic that needs tests rather than a preview: every case in
labelVars.spec.js is a value a number input can actually hold.
The stylesheet now carries fallbacks on its var() reads as well, but they are a
net, not the fix: a custom property set to garbage is substituted and then
dropped at computed value time, and the fallback does not apply - it only covers
a property that is absent entirely.
Reported as the CODE128 not appearing in the preview. It was appearing, in 44
of the 45 preset and layout combinations swept - as a 36 pixel stub. The code
box and the caption were both allowed to grow, so a caption of any length took
half the label and then kept taking, and on 1.00 x 0.50in stock a few words of
caption left a barcode too narrow to scan. Present, useless, and indisinguishable
from a failed render. The caption now takes the room it needs and no more, and a
CODE128 holds at least 40% of the label, or all of it when stacked: past that
there are too few narrow bars left to read, and a caption that wraps or clips is
the better trade.
So that a real failure can never again look like this one, an empty code box now
says so in red in the preview. It is screen-only - the marker must never reach a
printed label.
The settings were a narrow column with the preview trailing below them, which
put the labels being adjusted off the bottom of the screen. Settings on the
left, labels on the right in a column that stays in view and scrolls on its own,
folding back to one column on a narrow window.
That scrolling column is a print hazard worth naming: an ancestor with its own
overflow clips a multi-page print to whatever happened to be on screen. Print
resets it, and the check is a six-page two-sided run coming out as six pages
with the label as the only clipping box in the chain.
The back side landed last commit carrying text by default, and a back laid out
as text-only renders no code box at all. So a two-sided run came out with a
blank reverse, which reads as the code having failed rather than as a setting
doing exactly what it said. The back now defaults to carrying a code, takes its
own content per row, and chooses its own symbology - a QR on the front that
opens the record, a CODE128 on the back that the bench scanner already reads.
Text-only is refused while the back carries a code, and the contradiction is
reconciled on load, so a saved setting from the broken combination repairs
itself rather than printing another blank box of cards.
A picture can go on a label: above the code, beside it, or behind everything as
a watermark, on either side or both. The file is read in the browser and never
sent anywhere, which is what makes it usable at an air-gapped site, and it is
deliberately not saved between visits - a data URL runs to megabytes and would
take every sizing value with it when the quota gave out. The watermark says
plainly that it costs the scanner contrast.
The generator was a full-screen route with no navigation and a narrow column of
controls against the left edge. That shape exists so a print cannot put the
sidebar on label stock, which is a real hazard and the reason core's label pages
are built that way - but it is a hazard the print stylesheet can answer, and
style.css now hides the shell at print time. A tool someone spends ten minutes
in gets the navigation and the full width; the stock still gets nothing but
labels, confirmed against a print PDF rather than a preview.
Two smaller things found while checking the above. A test print paired each page
with a rendered code by loop position, while the codes are keyed to position in
the whole run, so a two-sided test card could carry the wrong code; the index
now travels with the page. And the back's dotted preview outline outspecified
the print reset, drawing a dashed rule down the edge of every second card.
Three things the code generator could not do, each of which had someone
working around it with a control that meant something else.
The gap between a code and its caption was the quiet zone. That is the
clear space a scanner needs around the code, so closing up a caption meant
shaving the thing that makes the code readable, and the only way to get a
tight label to scan was to push the caption further away than it looked
like it should be. Quiet zone now means the code's own margin and nothing
else; gap means the distance to the caption, and adds to the quiet zone
rather than eating into it. Each stock preset carries the gap that suits it.
Position had one pair of controls and they moved the label box on the
stock. That is the fix for a printer whose origin is off, and it is not the
fix for a code sitting in the wrong place on a label - but it was the only
lever there, so it got used for both. The label div is now the media and
holds still; everything printed sits in a content wrapper that Align,
Vertical and Content X/Y move within it. The old pair kept its behaviour
and is labelled Media X/Y.
A badge card has two sides and the generator only ever emitted one page per
card. The back can now carry the same code again, a fixed block of text,
its own per-row content, or nothing. Page order is a choice because the two
kinds of printer want opposite things: interleaved for a duplex card
printer, which takes pages two at a time, and grouped for a single-sided
one whose stack gets flipped and reloaded. A row that leaves its back
column empty still gets a blank back page - a page count that varies per
row shifts every later back onto the wrong front, which prints a box of
perfectly readable cards that are all wrong.
CSV parsing and page building moved to plugins/tools/frontend/labelPages.js
(committed in 875fde9), where the column contract and both page orders are
covered by tests rather than by looking at the preview.
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.
