Module: Idml::Render::Footnote

Defined in:
lib/idml/render/footnote.rb

Overview

Footnote semantics: story-scoped numbering, body-text marker synthesis, footnote-paragraph extraction, and the geometry of the bottom-of-frame footnote area (height reservation + separator rule). Emission of footnote text lines stays in TextFrameRenderer — it owns all canvas text drawing — while this module owns everything footnote-specific (MECE).

Numbering is sequential per story, honoring FootnoteOption's StartAt / Prefix / Suffix when the package declares them. Document-wide continuous numbering and per-section restart are not modeled.

Defined Under Namespace

Classes: Counter, Entry, PositionedRun

Constant Summary collapse

DEFAULT_RULE_WEIGHT = 
0.5
DEFAULT_RULE_GAP = 
3.0
MARKER_TEXT_SEPARATOR = 
" "

Class Method Summary collapse

Class Method Details

.counter_for(option) ⇒ Object 



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# File 'lib/idml/render/footnote.rb', line 51

def self.counter_for(option)
  Counter.new(option&.start_at)
end

.emit_separator(canvas, frame, y, option) ⇒ Object

Emits the separator rule at the top of the footnote area. Honors FootnoteOption RuleOn / RuleLineWeight / RuleWidth / RuleLeftIndent; defaults approximate InDesign (0.5pt rule spanning the column).



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# File 'lib/idml/render/footnote.rb', line 190

def self.emit_separator(canvas, frame, y, option)
  return if option&.rule_on == false

  thickness = separator_weight(option)
  return unless thickness.positive?

  stroke_rule(canvas, separator_left(frame, option), y,
              separator_width(frame, option), thickness)
end

.extract(element, number, condition_filter: nil, style_lookup: nil, option: nil) ⇒ Object

Extracts the footnote's paragraphs via StyleResolver and prefixes the first paragraph's first run with the marker text ("1 ", "n2." …) so the footnote reads as numbered.



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# File 'lib/idml/render/footnote.rb', line 80

def self.extract(element, number, condition_filter: nil,
                 style_lookup: nil, option: nil)
  paragraphs = StyleResolver.extract_container_paragraphs(
    element, condition_filter: condition_filter,
             style_lookup: style_lookup
  )
  marker = marker_text(number, option)
  prepend_marker(paragraphs, marker) unless marker.empty?
  paragraphs
end

.layout_entries(entries, frame, font, top_y, option = nil) ⇒ Object

Lays out all entries' paragraphs top-down starting at top_y. Returns [positioned_runs, bottom_y] where bottom_y is the cursor after the last line — the same walk drives both height measurement and rendering, so the reserved area always matches what gets drawn.



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# File 'lib/idml/render/footnote.rb', line 105

def self.layout_entries(entries, frame, font, top_y, option = nil)
  positioned = []
  cursor = top_y
  wrap_width = TextEngine::VerticalLayout.wrap_width(frame)

  entries.each_with_index do |entry, index|
    cursor -= (option&.space_between || 0).to_f if index.positive?
    entry.paragraphs.each do |paragraph|
      cursor = layout_paragraph(
        paragraph, frame, font, wrap_width, cursor, positioned
      )
    end
  end
  [positioned, cursor]
end

.marker_run(number, base, paragraphs, option) ⇒ Object

Builds the superscript marker run emitted into the body text where the footnote anchors. Inherits the base run's character styling so the marker matches its context; when the owning CSR has no text run, falls back to defaults.



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# File 'lib/idml/render/footnote.rb', line 65

def self.marker_run(number, base, paragraphs, option)
  marker = base || StyleResolver::StyledRun.new(
    point_size: StyleResolver::DEFAULT_POINT_SIZE,
  )
  marker = marker.dup
  marker.text = marker_text(number, option)
  marker.position = "Superscript"
  marker.footnote_number = number
  marker.footnote_paragraphs = paragraphs
  marker
end

.marker_text(number, option) ⇒ Object

Marker text shown in the body text (and prefixed to the footnote's first paragraph): Prefix + number + Suffix.



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# File 'lib/idml/render/footnote.rb', line 57

def self.marker_text(number, option)
  "#{option&.prefix}#{number}#{option&.suffix}"
end

.option(package) ⇒ Object

Returns the package's FootnoteOption (Preferences.xml), or nil when the package doesn't declare one.



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# File 'lib/idml/render/footnote.rb', line 46

def self.option(package)
  preferences = package&.preferences
  preferences&.footnote_option&.first
end

.reserved_height(entries, font, frame, option = nil) ⇒ Object

Height to reserve at the frame bottom for the entries: separator gap + the measured paragraph stack.



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# File 'lib/idml/render/footnote.rb', line 171

def self.reserved_height(entries, font, frame, option = nil)
  return 0.0 if entries.empty?

  content_bottom = TextEngine::VerticalLayout.bottom_limit(frame)
  _, bottom_y = layout_entries(entries, frame, font, content_bottom,
                               option)
  content_bottom - bottom_y + rule_gap(option)
end

.rule_gap(option) ⇒ Object

Vertical distance between the footnote area's top edge and the first footnote line — room for the separator rule.



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# File 'lib/idml/render/footnote.rb', line 182

def self.rule_gap(option)
  option&.spacer || DEFAULT_RULE_GAP
end