Module: Pdfrb::Conformance::PdfUA2Deep

Defined in:

lib/pdfrb/conformance/pdf_ua2_deep.rb

Overview

PDF/UA-2 (ISO 14289-2) deep checks. PDF/UA-2 is rooted in PDF 2.0 and adds stricter requirements on top of PDF/UA-1:

* PDF version >= 2.0
* Structure tree with consistent /RoleMap
* Heading hierarchy (H1-H6) without skipping levels
* Every Figure, Formula, Table has /Alt or /ActualText

Constant Summary

RULESET =

RuleSet.new("PDF/UA-2-deep").tap do |rs|
  rs.register(Rule.new(
                id: "ua2-1",
                description: "PDF/UA-2 requires PDF 2.0",
                severity: :error,
                spec_clause: "ISO 14289-2 4.1",
                check: ->(doc) {
                  v = doc.version.to_s
                  next nil if v >= "2.0"

                  Violation.new(
                    rule_id: "ua2-1",
                    message: "PDF/UA-2 requires PDF 2.0 (was #{v})",
                    object: "Header",
                    severity: :error,
                    spec_clause: "ISO 14289-2 4.1"
                  )
                }
              ))

  rs.register(Rule.new(
                id: "ua2-2",
                description: "Heading hierarchy must not skip levels",
                severity: :warning,
                spec_clause: "ISO 14289-2 7.3",
                check: ->(doc) {
                  vs = []
                  prev_level = 0
                  TaggedPdf.walk_structure(doc) do |elem|
                    s = elem[:S]&.to_s
                    next unless s&.match?(/\AH([1-6])\z/)

                    level = Regexp.last_match(1).to_i
                    if level > prev_level + 1 && prev_level.positive?
                      vs << Violation.new(
                        rule_id: "ua2-2",
                        message: "Heading H#{level} jumps from H#{prev_level}",
                        object: "StructElem/#{s}",
                        severity: :warning,
                        spec_clause: "ISO 14289-2 7.3"
                      )
                    end
                    prev_level = level
                  end
                  vs.empty? ? nil : vs
                }
              ))

  rs.register(Rule.new(
                id: "ua2-3",
                description: "Formula elements require /Alt or /ActualText",
                severity: :warning,
                spec_clause: "ISO 14289-2 7.9",
                check: ->(doc) {
                  vs = []
                  TaggedPdf.walk_structure(doc) do |elem|
                    next unless elem[:S] == :Formula
                    next if elem[:Alt] || elem[:ActualText]

                    vs << Violation.new(
                      rule_id: "ua2-3",
                      message: "Formula without /Alt or /ActualText",
                      object: "StructElem/Formula",
                      severity: :warning,
                      spec_clause: "ISO 14289-2 7.9"
                    )
                  end
                  vs.empty? ? nil : vs
                }
              ))
end

Class Method Summary

• .validate(document) ⇒ Object

Class Method Details

.validate(document) ⇒ Object

# File 'lib/pdfrb/conformance/pdf_ua2_deep.rb', line 87

def validate(document)
  RULESET.validate(document)
end