type: qr_code

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A QR code item. Content comes from text (static, with {key} interpolation) or data (a single bound value) — exactly like a text item; the engine encodes whatever string it gets (URL / number / opaque token, no semantics). Encoded at layout time into vector module rectangles, so it needs no asset pipeline and works inside repeat cells with element-scoped bindings — and in flow, absolute, bands, and containers (flex or absolute placement).

Syntax

- type: qr_code
  box: { w: 60, h: 60 }             # w/h required
  data: { key: url }                # …or text: "https://example.com/{code}"
  errorCorrection: medium           # low | medium | quartile | high
  style: { backgroundColor: "#ffffff" }   # the scannable white backing

Keys

Key	Type	Default	Description
text / data		one required	Content, exactly like text.md — scope-aware, so per-element inside cells.
bindings	map of name → binding	unset	Named declarations for this item's {name} interpolations — the option set the bare {key} grammar cannot carry, incl. a key outside [A-Za-z0-9_.] (data-binding.md).
box.w / box.h	Length	required	The code draws square on the smaller content-box side, centered, with the ISO 18004 4-module quiet zone inside the box.
errorCorrection	low | medium | quartile | high	medium	Tolerated damage ~7/15/25/30%; higher levels need more modules for the same content.
style / styleNames			Decoration only: backgroundColor paints under the modules (the usual white backing), plus borderWidth/borderColor.

Guards

• The encoded string is the formatted value, like any text placement — a field with enum display labels encodes its LABEL; bind format: value to encode the machine value (data-binding.md).
• Content is capped at 1 KiB (qr_content_too_long) — params are untrusted and modules fan out into tree items.
• Modules smaller than 1 pt draw but warn qr_module_too_small (scanners may struggle).

Limitations

• box.w/box.h are required (qr_missing_size).
• Content is capped at 1 KiB; past that the item is skipped (qr_content_too_long).
• Modules under 1 pt still draw but warn (qr_module_too_small) — a scanner may not read them.
• QR only. No other symbology, and no barcode types.
• The engine encodes the string it is given and reads no semantics from it: a payload's validity is the host's business.

Diagnostics

Code	Meaning
qr_missing_size	box.w/box.h absent
empty_qr_code_item	neither text nor data set
qr_content_too_long	content over 1 KiB; skipped
qr_module_too_small	modules < 1 pt at the authored size; drawn anyway

Capability key: qr_code.

See also

• image.md — raster/SVG assets (QR needs none)
• repeat.md — per-element codes in n-up cells