Module: Yaml::Converter::Renderer::PdfPrawn

Defined in:
lib/yaml/converter/renderer/pdf_prawn.rb

Overview

Native PDF rendering using prawn.
Basic layout: title lines, YAML block in monospace, notes as italic paragraphs.

For PDF rendering via pandoc, see PandocShell.

Class Method Summary collapse

Class Method Details

.extract_notes(markdown) ⇒ Array<String>

Extract note strings from Markdown blockquote lines.

Parameters:

  • markdown (String)

Returns:

  • (Array<String>) 


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# File 'lib/yaml/converter/renderer/pdf_prawn.rb', line 104

def extract_notes(markdown)
  markdown.lines.grep(/^> NOTE:/).map { |l| l.sub(/^> NOTE:\s*/, "").strip }
end

.fenced_yaml(markdown) ⇒ Array<String>

Return the lines inside the first fenced ```yaml block.

Parameters:

  • markdown (String)

Returns:

  • (Array<String>) 


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# File 'lib/yaml/converter/renderer/pdf_prawn.rb', line 84

def fenced_yaml(markdown)
  inside = false
  lines = []
  markdown.each_line do |l|
    if l.start_with?("```yaml")
      inside = true
      next
    elsif inside && l.strip == "```"
      inside = false
      break
    elsif inside
      lines << l.rstrip
    end
  end
  lines
end

.header_lines(markdown) ⇒ Array<String>

Extract leading # Title lines.

Parameters:

  • markdown (String)

Returns:

  • (Array<String>) 


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# File 'lib/yaml/converter/renderer/pdf_prawn.rb', line 77

def header_lines(markdown)
  markdown.lines.take_while { |l| l.start_with?("# ") }.map { |l| l.sub(/^# /, "").strip }
end

.render(markdown:, out_path:, options: {}) ⇒ Boolean

Render a PDF document from the given markdown string.

Parameters:

  • markdown (String) —

    Markdown that includes fenced YAML and blockquote notes

  • out_path (String) —

    Destination PDF path

  • options (Hash) (defaults to: {}) —

    PDF options (see Config defaults: page size, margins, font sizes, two-column notes)

Options Hash (options:):

  • :pdf_page_size (String) — default: "LETTER"
  • :pdf_margin (Array<Integer>) — default: [36, 36, 36, 36]
  • :pdf_title_font_size (Integer) — default: 14
  • :pdf_body_font_size (Integer) — default: 11
  • :pdf_yaml_font_size (Integer) — default: 9
  • :pdf_two_column_notes (Boolean) — default: false

Returns:

  • (Boolean) —

    true if rendering succeeded



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# File 'lib/yaml/converter/renderer/pdf_prawn.rb', line 25

def render(markdown:, out_path:, options: {})
  require "prawn"

  notes = extract_notes(markdown)
  yaml_section = fenced_yaml(markdown)
  title_lines = header_lines(markdown)

  page_size = options[:pdf_page_size] || "LETTER"
  margin = options[:pdf_margin] || [36, 36, 36, 36]
  title_fs = options[:pdf_title_font_size] || 14
  body_fs = options[:pdf_body_font_size] || 11
  yaml_fs = options[:pdf_yaml_font_size] || 9
  two_col = !!options[:pdf_two_column_notes]

  Prawn::Document.generate(out_path, page_size: page_size, margin: margin) do |pdf|
    pdf.font_size(title_fs)
    title_lines.each { |l| pdf.text(l, style: :bold) }
    pdf.move_down(10) if title_lines.any?

    if two_col && notes.any?
      # Create two columns: left for YAML, right for notes
      col_gap = 16
      col_width = (pdf.bounds.width - col_gap) / 2.0
      pdf.bounding_box([pdf.bounds.left, pdf.cursor], width: col_width, height: pdf.cursor) do
        pdf.font_size(yaml_fs)
        pdf.font("Courier") { yaml_section.each { |l| pdf.text(l) } }
      end
      pdf.bounding_box([pdf.bounds.left + col_width + col_gap, pdf.cursor], width: col_width, height: pdf.cursor) do
        pdf.font_size(body_fs)
        notes.each { |n| pdf.text("NOTE: #{n}", style: :italic) }
      end
    else
      pdf.font_size(yaml_fs)
      pdf.font("Courier") { yaml_section.each { |l| pdf.text(l) } }
      pdf.move_down(10)
      unless notes.empty?
        pdf.font_size(body_fs)
        notes.each { |n| pdf.text("NOTE: #{n}", style: :italic) }
      end
    end

    pdf.number_pages("Page <page> of <total>", at: [pdf.bounds.right - 100, 0])
  end
  true
rescue StandardError => e
  warn("prawn pdf failed: #{e.class}: #{e.message}")
  false
end