label-snip

Label Snip

Chrome extension that trims a shipping label PDF (a 4×6 label on a letter or A4 page) down to a print-ready 4×6 PDF. Built for Vinted, works on any site whose label is a single picture on the page. Everything runs on your computer.

Install

Get Label Snip on the Chrome Web Store, then pin it: puzzle-piece icon in the toolbar → pin Label Snip.

Install from source

1. Download or clone this repo.
2. Open chrome://extensions.
3. Turn on Developer mode (top right).
4. Click Load unpacked and pick the extension folder.
5. Pin it: puzzle-piece icon in the toolbar → pin Label Snip.

After changing any file, click the reload ↻ icon on the Label Snip card in chrome://extensions.

Use

1. Open the label so the PDF is showing in a Chrome tab.
2. Click the Label Snip icon. A new tab opens with just the 4×6 label.
3. Press Ctrl+P, choose your label printer, set paper size to 4 × 6 in (100mm x 150mm) and scale to Default / 100% (not “Fit”), then print.

New sites

The first time you use it on a site other than Vinted, Label Snip asks “Allow Label Snip to read labels from site?”. Click Allow, then confirm Chrome’s own prompt. Chrome words that prompt as “Read and change your data on site”, which is its standard wording for any site access; Label Snip only downloads the PDF from the tab you clicked.

Chrome remembers the OK. To see or remove approved sites: chrome://extensions → Label Snip → Details → Site access.

If the site only shows the label when you’re signed in, that works too: Label Snip uses your existing login.

What it can’t do (yet)

• Labels drawn as text and lines instead of one picture → “Couldn’t find a label in this PDF.”
• Labels the site builds inside the browser (the tab address starts with blob:) → “Label Snip can’t read this tab.”
• Pages served over plain http:// → “Label Snip only reads secure (https) pages.”

How it works

• background.js: on icon click, opens crop.html with the clicked tab’s address.
• crop.js: asks for the site’s OK if needed, downloads the PDF (with your login cookies), calls labelcrop.js, shows the result in Chrome’s PDF viewer.
• labelcrop.js: finds the largest image on each page (the label), shrinks the page boxes to it, turns it upright if it’s sideways, and drops pages with no label. The label image isn’t re-rendered, so barcodes stay sharp.
• lib/pdf-lib.js: pdf-lib 1.17.1 (MIT), unminified so it’s easy to read.

Vinted’s label host (svc-shipping-labels.s3.eu-central-1.amazonaws.com) is approved from install, so Vinted never shows the Allow step.

Privacy

Label Snip has no server, no account and no analytics. See the privacy policy.

Faint prints on a thermal printer

That’s a printer setting, not the PDF (Label Snip doesn’t change the label image). In Windows → Printers & scanners → your printer → Printing preferences, raise Density (or Darkness) and lower Speed; slower prints darker. If there’s a Dither / Threshold option, pick Threshold. On a Nelko PL70e-BT these are on the Parameters tab (density default 8 of 15, speed default 4).

License

MIT. Bundled pdf-lib is also MIT (extension/lib/pdf-lib.LICENSE.md).

Tests

node --test test/crop.test.js

To also check a real label: set LABEL_SAMPLE to a label PDF path (and optionally LABEL_OUT to save the cropped result).

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