How it works, and how it's tested

Sticker Bench is a static web page. All layout, image handling and file generation happen in your browser.

Geometry

• All measurements are kept in millimetres; inches are converted at exactly 25.4 mm.
• Printable area = page minus margins. The bleed of every sticker must sit inside it, so a sticker's cut line stays at least the bleed distance inside the margins.
• Spacing is the minimum distance between any two cut lines (horizontal or vertical gap). It must be ≥ 2 × bleed.
• With calibration marks on, page 1 reserves a 56 × 11 mm block at the bottom-left of the printable area, plus clearance.

Automatic packing

Auto-arrange uses the MaxRects rectangle-packing algorithm. Each sticker is treated as its rectangular bounding box, extended by the spacing. It tries 12 combinations of sort order (longest side, area, height, width) and placement rule (best short-side fit, best area fit, bottom-left), then keeps the result with the fewest sheets and the fullest early sheets.

Limitations: this is a bounding-box approximation, not contour nesting. Round or irregular stickers are packed as rectangles, so space between curves isn't used. The result is good, not proven optimal; a hand arrangement can sometimes fit more. Rotation is limited to 90° steps, and only for designs where you allow it.

Manual editing

When you drag or rotate a sticker, the studio checks the new position against the same rules: it must stay in bounds, keep its spacing from every neighbour, and avoid the calibration block. Problems are listed and outlined in red. Every change can be undone.

Output files

• PDF: page size equals your paper size (1 mm = 72/25.4 pt). Images are embedded losslessly at their original pixels, with transparency. The file asks viewers not to scale when printing.
• SVG: width and height in mm, with a viewBox in mm. The cut lines only SVG has the same page size and positions, with no artwork.
• PNG: rendered at the dpi you choose, with that dpi recorded in the file's pHYs chunk, so pixels = page inches × dpi.

Cut lines are drawn as thin outlines in the colour you choose. They're a visual guide. Sticker Bench makes no claim of compatibility with any cutting machine, its software or its registration marks.

Tests

• Packing: hand-checked grids (e.g. 3 × 5 = 15 of a known size) and a randomized property test over 400 random sheets and design mixes. Each layout is checked by an independent brute-force checker for overlaps, spacing, bounds and calibration clearance, and checked against an area lower bound on sheet count.
• Exports: the generated PDF and SVG are parsed back to confirm page size, sticker positions and aspect ratios. PDFs are also checked with Poppler (pdfinfo, and rasterizing to measure the 50 mm bar). PNG dpi metadata is parsed.
• Safety: malicious SVGs (scripts, event handlers, external links, entities), truncated and oversized images, and tampered project files are tested to fail with a clear message.
• Browser: headless Chrome runs the studio on desktop and mobile sizes: imports, drag, undo, rotate, duplicate, delete, every download, and project save/reopen. Every network request is logged to confirm no artwork leaves the page.

Who runs this

Sticker Bench is operated by SPAZ Power LLC. It's free to use, with no account. Feedback and bug reports: 55paz.power@gmail.com. Always print a test sheet on plain paper before using sticker paper. We can't be responsible for paper, ink or materials.