Module: Pdfrb::Conformance::PdfX

Defined in:
lib/pdfrb/conformance/pdf_x.rb

Overview

PDF/X conformance profiles (ISO 15930). PDF/X is the graphic arts exchange standard for print production. Key constraints:

PDF/X-1a (ISO 15930-1): CMYK + spot only, no RGB, no live ICC
PDF/X-3  (ISO 15930-3): allows calibrated RGB and Lab
PDF/X-4  (ISO 15930-7): allows transparency and layers
PDF/X-6  (ISO 15930-11): PDF 2.0 based

Shared requirements across all X profiles:

* Output intent required (/OutputIntents with /GTS_PDFX)
* BleedBox and TrimBox required
* All fonts embedded
* No encryption
* No actions (/AA), no JavaScript
* /Trapped key present (True/False/Unknown)

Constant Summary collapse

SHARED =

rubocop:disable Metrics/BlockLength

RuleSet.new("PDF/X-shared").tap do |rs| # rubocop:disable Metrics/BlockLength
  rs.register(Rule.new(
                id: "px-1",
                description: "Output intent required",
                severity: :error,
                spec_clause: "ISO 15930 §6.1",
                check: ->(doc) {
                  next nil if has_pdfx_output_intent?(doc)

                  Violation.new(rule_id: "px-1",
                                message: "PDF/X requires a /GTS_PDFX output intent",
                                object: "Catalog", severity: :error,
                                spec_clause: "ISO 15930 §6.1")
                }
              ))

  rs.register(Rule.new(
                id: "px-2",
                description: "TrimBox or ArtBox required on every page",
                severity: :error,
                spec_clause: "ISO 15930 §6.2.3",
                check: ->(doc) {
                  violations = []
                  doc.pages.each do |page|
                    next if page.value[:TrimBox] || page.value[:ArtBox]

                    violations << Violation.new(
                      rule_id: "px-2",
                      message: "Page missing /TrimBox (required for PDF/X)",
                      object: page.oid, severity: :error,
                      spec_clause: "ISO 15930 §6.2.3"
                    )
                  end
                  violations.empty? ? nil : violations
                }
              ))

  rs.register(Rule.new(
                id: "px-3",
                description: "All fonts must be embedded",
                severity: :error,
                spec_clause: "ISO 15930 §6.3",
                check: ->(doc) {
                  violations = []
                  doc.pages.each do |page|
                    resources = page.value[:Resources]
                    next unless resources

                    fonts = if resources.is_a?(Pdfrb::Model::Cos::Dictionary)
                              resources.value[:Font]
                            else
                              resources[:Font]
                            end
                    next unless fonts

                    fonts_hash = fonts.is_a?(Pdfrb::Model::Cos::Dictionary) ? fonts.value : fonts
                    fonts_hash&.each_value do |ref|
                      font = ref.is_a?(Pdfrb::Model::Reference) ? doc.object(ref) : ref
                      next unless font

                      fd = font[:FontDescriptor]
                      next if fd

                      violations << Violation.new(
                        rule_id: "px-3",
                        message: "Font /#{font[:BaseFont]} not embedded",
                        object: font[:BaseFont], severity: :error,
                        spec_clause: "ISO 15930 §6.3"
                      )
                    end
                  end
                  violations.empty? ? nil : violations
                }
              ))

  rs.register(Rule.new(
                id: "px-4",
                description: "Encryption prohibited",
                severity: :error,
                spec_clause: "ISO 15930 §6.1.3",
                check: ->(doc) {
                  next nil unless doc.trailer && doc.trailer[:Encrypt]

                  Violation.new(rule_id: "px-4",
                                message: "PDF/X prohibits encryption",
                                object: "trailer", severity: :error,
                                spec_clause: "ISO 15930 §6.1.3")
                }
              ))

  rs.register(Rule.new(
                id: "px-5",
                description: "/Trapped key required",
                severity: :error,
                spec_clause: "ISO 15930 §6.1.6",
                check: ->(doc) {
                  info = PdfX.info_dict(doc)
                  next nil if info && info[:Trapped]

                  Violation.new(rule_id: "px-5",
                                message: "Document Info /Trapped key required (True, False, or Unknown)",
                                object: "Info", severity: :error,
                                spec_clause: "ISO 15930 §6.1.6")
                }
              ))

  rs.register(Rule.new(
                id: "px-6",
                description: "No JavaScript or form actions",
                severity: :error,
                spec_clause: "ISO 15930 §6.5",
                check: ->(doc) {
                  violations = []
                  doc.each_indirect_object do |obj|
                    next unless obj.is_a?(Pdfrb::Model::Cos::Dictionary)

                    s = obj[:S]
                    next unless [:JavaScript, :JS, :Launch, :URI].include?(s)

                    violations << Violation.new(
                      rule_id: "px-6",
                      message: "Action /#{s} prohibited in PDF/X",
                      object: obj.oid, severity: :error,
                      spec_clause: "ISO 15930 §6.5"
                    )
                  end
                  violations.empty? ? nil : violations
                }
              ))
end
X1A =

X-1a: strictest — CMYK + spot only

RuleSet.new("PDF/X-1a").tap do |rs|
  SHARED.rules.each { |r| rs.register(r) }
  rs.register(Rule.new(
                id: "x1a-1",
                description: "PDF/X-1a: no RGB or Lab color spaces",
                severity: :error,
                spec_clause: "ISO 15930-1 §6.3.8",
                check: ->(doc) {
                  violations = []
                  scan_color_spaces(doc) do |cs, oid|
                    case cs.to_s
                    when "DeviceRGB", "CalRGB", "CalGray", "Lab"
                      violations << Violation.new(
                        rule_id: "x1a-1",
                        message: "PDF/X-1a prohibits #{cs} color space",
                        object: oid, severity: :error,
                        spec_clause: "ISO 15930-1 §6.3.8"
                      )
                    end
                  end
                  violations.empty? ? nil : violations
                }
              ))
end
X3 =

X-3: allows calibrated RGB and Lab

RuleSet.new("PDF/X-3").tap do |rs|
  SHARED.rules.each { |r| rs.register(r) }
end
X4 =

X-4: allows transparency and layers

RuleSet.new("PDF/X-4").tap do |rs|
  SHARED.rules.each { |r| rs.register(r) }
end

Class Method Summary collapse

Class Method Details

.has_pdfx_output_intent?(doc) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pdfrb/conformance/pdf_x.rb', line 170

def has_pdfx_output_intent?(doc)
  intents = doc.catalog.value[:OutputIntents]
  return false unless intents

  intents = [intents] unless intents.is_a?(::Array)
  intents.any? do |ref|
    obj = ref.is_a?(Pdfrb::Model::Reference) ? doc.object(ref) : ref
    obj && obj.value[:S] == :GTS_PDFX
  end
end

.info_dict(doc) ⇒ Object 



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# File 'lib/pdfrb/conformance/pdf_x.rb', line 181

def info_dict(doc)
  info_ref = doc.trailer && doc.trailer[:Info]
  return nil unless info_ref

  doc.object(info_ref)
end

.profiles ⇒ Object 



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# File 'lib/pdfrb/conformance/pdf_x.rb', line 23

def profiles
  { x1a: X1A, x3: X3, x4: X4 }
end

.rule_set_for(level) ⇒ Object 



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# File 'lib/pdfrb/conformance/pdf_x.rb', line 31

def rule_set_for(level)
  case level.to_s
  when /\Ax1/i then X1A
  when /\Ax3/i then X3
  else X4
  end
end

.scan_color_spaces(doc, &block) ⇒ Object 



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# File 'lib/pdfrb/conformance/pdf_x.rb', line 224

def scan_color_spaces(doc, &block)
  doc.each_indirect_object do |obj|
    next unless obj.is_a?(Pdfrb::Model::Cos::Dictionary)

    cs = obj.value[:ColorSpace]
    next unless cs

    yield_color_space(cs, obj.oid, &block)
  end
end

.validate(document, level: :x4) ⇒ Object 



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# File 'lib/pdfrb/conformance/pdf_x.rb', line 27

def validate(document, level: :x4)
  rule_set_for(level).validate(document)
end