mtlcl410andClaude Opus 5.5
9dfc91e0e8
A cover counted only when it hid 40% of the line's words or box, so a black box over one number in a long line, and an unapplied redaction mark over it, audited clean while the number was still extractable. A cover that hides half of any one word now counts as well. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01RUNQSPVXx3dDBabRZHAnjz
pdfcraft-audit
Layer L4 (may use edit): verification tooling, the faux-redaction audit.
let findings: Vec<Finding> = audit_redactions(&doc)?; // page, kind, rect, covered_text
It reports two kinds of finding:
- faux redaction: an opaque filled rectangle painted after text it overlaps, dark enough against the text's colour (WCAG contrast below 3) to hide it, while the text is still extractable underneath;
- unapplied mark: a Redact annotation that was marked but never applied.
A properly applied redaction removes the text, so it never flags. Page backgrounds, table shading and highlights don't either: they're painted before the text, or light against it.
A rectangle covers a text line when it hides at least half of one of the line's words, at
least 40% of the area of the words the line draws, or at least 40% of the line's box together
with a positive-area intersection with one of its words. The gap an applied redaction leaves (a TJ adjustment where the text was) is in the line's box but
holds no word, so a redaction box over it alone does not count.
Limits, by design and documented rather than hidden:
- only filled rectangles count as covers, drawn with
reor as a singlem/lsubpath whose corners form an axis-aligned rectangle (not other paths, shadings or patterns), and a translucent one (/cabelow 1) is not flagged; - covers inside form XObjects are found, but only text drawn directly in the page content is checked under them;
- annotation rectangles are compared in unrotated user space, so
/Rotatepages may misalign; - a cover that hides less than half of every word it touches, less than 40% of a line's box and less than 40% of its words (a sliver of a long value) is not flagged.
It fails closed: an undecodable content stream, malformed /Annots, form XObjects nested deeper
than 32 or in a cycle, or a walk past the operator bound is an error, never "no findings".
Surfaces: the doc_audit_redactions automation tool and pdfcraft-cli audit. Both report each
rectangle in points from the top-left of the page as displayed (y down, after /Rotate), like
the other tools; AuditFinding::rect itself stays in PDF user space.