Module: Idml::Render::DropCap

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

Overview

Computes drop-cap geometry for a paragraph. IDML's DropCapLines (M) and DropCapCharacters (N) declare that the first N characters of the paragraph should render at M-lines-tall and the next M text lines should wrap to the right of the drop cap.

The helper returns a DropCapLayout struct with the drop cap text, font size, width (for wrap offset), and total height. Returns nil when the paragraph doesn't declare drop caps.

Defined Under Namespace

Classes: DropCapLayout

Class Method Summary collapse

Class Method Details

.active?(paragraph) ⇒ Boolean

True when the paragraph declares an active drop cap (both DropCapLines and DropCapCharacters are positive integers).



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# File 'lib/idml/render/drop_cap.rb', line 36

def self.active?(paragraph)
  return false unless paragraph
  return false unless paragraph.drop_cap_lines.to_i.positive?

  paragraph.drop_cap_characters.to_i.positive?
end

.extract_drop_cap_text(paragraph, n) ⇒ Object

Pulls the first N characters from the paragraph's first run. If the first run is shorter than N, takes from subsequent runs until N chars are accumulated (rare — drop caps typically use 1-2 chars).



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# File 'lib/idml/render/drop_cap.rb', line 47

def self.extract_drop_cap_text(paragraph, n)
  runs = paragraph.runs
  return nil if runs.empty?

  collected = +""
  runs.each do |run|
    needed = n - collected.length
    break if needed <= 0

    collected << run.text[0, needed]
    break if collected.length >= n
  end
  collected
end

.layout(paragraph, font_metrics:, base_size:, leading:) ⇒ Object

Returns a DropCapLayout for the paragraph, or nil when drop caps aren't declared. font_metrics measures the drop-cap text's natural width. base_size is the paragraph's normal font size (drop cap is enlarged relative to it).



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# File 'lib/idml/render/drop_cap.rb', line 23

def self.layout(paragraph, font_metrics:, base_size:, leading:)
  return nil unless active?(paragraph)
  return nil unless font_metrics

  chars = paragraph.drop_cap_characters.to_i
  lines = paragraph.drop_cap_lines.to_i
  return nil if chars <= 0 || lines <= 0

  build_layout(paragraph, font_metrics, base_size, leading, chars, lines)
end