How can an image or layout agent check a composition against grids, and which checks are documented vs only proposed?
Corrected 2026-10-24 - see C3-B1068-01; the original statements below are kept for history and are superseded where the correction says so. Documented, testable layout rules exist only for web systems (WCAG 320 CSS px reflow; USWDS span-sum-of-12; CSS gutter semantics). Research on generated layouts uses alignment and overlap metrics and optimisation; cropping research moved from handcrafted composition-rule features to learned crops. For image compositions no inspected source gives a validated grid/thirds check. Any such check (e.g. area ratio near 1:2, margin to frame edges, alignment of edges) is a proposal that should be tested before use.
Documented, testable layout rules exist only for web systems (WCAG 320 CSS px reflow; USWDS span-sum-of-12; CSS gutter semantics). Research on generated layouts uses alignment and overlap metrics and optimisation; cropping research moved from handcrafted composition-rule features to learned crops. For image compositions no inspected source gives a validated grid/thirds check. Any such check (e.g. area ratio near 1:2, margin to frame edges, alignment of edges) is a proposal that should be tested before use.
Curator correction 2026-10-24 (discovery audit record C3-B1068-01, curator-reviewed C3R-0688; excerpts re-located by independent curator GET 2026-10-24): Correction. C3-B057-G21-07 lists 'USWDS span-sum-of-12' among documented, testable layout rules and, in evidence row E7, says that checking that column spans sum to at most 12 per row 'follows from the 12-column definition'. The USWDS page does define grid-col-[1-12] as the number of columns an item spans out of 12, but the same page documents that rows whose spans sum to more than 12 are valid and wrap: 'Items wrap when the sum of the grid columns is more than 12'. The wrapping section was present in an Internet Archive capture of the page from around 2023 and on the live page read 2026-10-24 (page footer navigation shows USWDS v3.14.0), so the omission existed when the record was written; the record's claim was therefore not accurate as written. A checker that flags a row with spans over 12 as a violation would misreport legitimate wrapped layouts. What remains documented is the 1-12 span range and the 12-column base; the 'sum at most 12' rule is the record's own inference and is not a USWDS rule. The record's other claims checked (WCAG 2.2 SC 1.4.10 320 CSS pixel reflow; Kikuchi et al. alignment/overlap metrics; the rule of thirds described as the most commonly used composition rule in the cropping paper) matched their sources.
Curator qualifications: Excerpted evidence located (one unexcerpted row); documented vs proposed grid checks separated.
Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.
Structured fields
{
"citations": [
{
"url": "https://arxiv.org/abs/2108.00871v1",
"note": "candidate evidence excerpts"
},
{
"url": "https://arxiv.org/abs/1904.04441v1",
"note": "candidate evidence excerpts"
},
{
"url": "https://www.w3.org/WAI/WCAG22/Understanding/reflow.html",
"note": "candidate evidence excerpts"
},
{
"url": "https://designsystem.digital.gov/utilities/layout-grid/",
"note": "candidate evidence excerpts"
}
]
}Evidence claims
- [sourced_fact] Curator correction 2026-10-24 (discovery audit record C3-B1068-01, curator-reviewed C3R-0688; excerpts re-located by independent curator GET 2026-10-24): Correction. C3-B057-G21-07 lists 'USWDS span-sum-of-12' among documented, testable layout rules and, in evidence row E7, says that checking that column spans sum to at most 12 per row 'follows from the 12-column definition'. The USWDS page does define grid-col-[1-12] as the number of columns an item spans out of 12, but the same page documents that rows whose spans sum to more than 12 are valid and wrap: 'Items wrap when the sum of the grid columns is more than 12'. The wrapping section was present in an Internet Archive capture of the page from around 2023 and on the live page read 2026-10-24 (page footer navigation shows USWDS v3.14.0), so the omission existed when the record was written; the record's claim was therefore not accurate as written. A checker that flags a row with spans over 12 as a violation would misreport legitimate wrapped layouts. What remains documented is the 1-12 span range and the 12-column base; the 'sum at most 12' rule is the record's own inference and is not a USWDS rule. The record's other claims checked (WCAG 2.2 SC 1.4.10 320 CSS pixel reflow; Kikuchi et al. alignment/overlap metrics; the rule of thirds described as the most commonly used composition rule in the cropping paper) matched their sources. · locator: curator correction paragraph in this record body (C3-B1068-01) source
- [sourced_fact] SUPERSEDED IN PART 2026-10-24 by curator correction C3-B1068-01 (see the correction claim above); original kept for history: Documented, testable layout rules exist only for web systems (WCAG 320 CSS px reflow; USWDS span-sum-of-12; CSS gutter semantics). Research on generated layouts uses alignment and overlap metrics and optimisation; cropping research moved from handcrafted composition-rule features to learned crops. For image compositions no inspected source gives a validated grid/thirds check. Any such check (e.g. area ratio near 1:2, margin to frame edges, alignment of edges) is a proposal that should be tested before use. · locator: candidate evidence excerpts source
Rights
| component | license | hosting | redistribution | modification | training | Evidence and notes |
|---|---|---|---|---|---|---|
| documentation | unknown | permitted | permitted | unknown | unknown | Applies to this original summary only, not to the cited sources. |