Module: Arrolio::Renderer::Pdf::FontEmbedding

Included in:
Arrolio::Renderer::Pdf
Defined in:
lib/arrolio/renderer/pdf/font_embedding.rb

Overview

Extracted concern: Pdfrb coupling points kept out of the emission path.

Instance Method Summary collapse

Instance Method Details

#attach_to_resources(font_name, ref) ⇒ Object 



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# File 'lib/arrolio/renderer/pdf/font_embedding.rb', line 39

def attach_to_resources(font_name, ref)
  catalog = @document.catalog
  res = catalog.value[:Resources]
  Arrolio::Logger.debug "attach_to_resources: Resources=#{res.class}"
  unless res.is_a?(Hash) && res[:Font].is_a?(Hash)
    catalog.value[:Resources] = { Font: {} }
  end
  font_hash = catalog.value[:Resources][:Font]
  key = (format('EF%d', (font_hash.length + 1))).to_sym
  font_hash[key] = ref
  @embedded_resource_keys ||= {}
  @embedded_resource_keys[font_name] = key
end

#collect_codepoints(page, by_font) ⇒ Object 



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# File 'lib/arrolio/renderer/pdf/font_embedding.rb', line 53

def collect_codepoints(page, by_font)
  (page.static_regions.values + page.regions.values).each do |region|
    region.placed_boxes.each do |box|
      next unless box.kind == :text
      next unless box.data.is_a?(Hash) && box.data[:lines]

      box.data[:lines].each do |line|
        next unless line.is_a?(TextLayout::Line)
        line.placed_runs.each do |pr|
          next unless pr.run.is_a?(InlineRun)
          # Collect under the RUN'S font name, not the
          # paragraph's. Italic/bold runs have different
          # font_names and need their own subsets.
          run_font = pr.run.style.font_name
          next unless @font_paths.key?(run_font)
          pr.run.text.each_codepoint { |cp| by_font[run_font] << cp }
        end
      end
    end
  end
end

#prepare_embedded_fonts(pages) ⇒ Object

Pre-scan all pages, collect codepoints per font family, then call Font::Embedder for each font_path.



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# File 'lib/arrolio/renderer/pdf/font_embedding.rb', line 11

def prepare_embedded_fonts(pages)
  return if @font_paths.empty?

  codepoints = Hash.new { |h, k| h[k] = [] }
  pages.each { |page| collect_codepoints(page, codepoints) }
  Arrolio::Logger.debug "collected codepoints for fonts: #{codepoints.keys.inspect}"
  @font_paths.each do |font_name, path|
    exists = File.exist?(path)
    has_cp = codepoints.key?(font_name)
    cp_count = codepoints[font_name]&.length || 0
    Arrolio::Logger.debug "font #{font_name}: exists=#{exists} cp=#{cp_count}"
    next unless exists
    next unless has_cp

    cps = codepoints[font_name].uniq
    embedder = Font::Embedder.new(@document, path,
                                  base_font_name: font_name)
    ref = embedder.embed(cps)
    attach_to_resources(font_name, ref)
    @font_embedders[font_name] = embedder
    @font_encoders[font_name] = Font::TextEncoder.new(embedder)
    @font_refs[font_name] = ref
  rescue StandardError => e
    Arrolio::Logger.warn "embed failed for #{font_name}: #{e.class}: #{e.message[0,100]}"
    Arrolio::Logger.debug e.backtrace.first(5).join("\n")
  end
end