class Prawn::FontMetricCache

Cache used internally by Prawn::Document instances to calculate the width of various strings for layout purposes.

@private

Constants

CacheEntryMonkeyPatch

Public Instance Methods

width_of(string, options) click to toggle source
# File lib/prawn/font_metric_cache.rb, line 9
def width_of(string, options)
  f = if options[:style]
        # override style with :style => :bold
        @document.find_font(@document.font.family, style: options[:style])
      else
        @document.font
      end

  encoded_string = f.normalize_encoding(string)

  key = CacheEntryMonkeyPatch.new(f, @document.font_size, options, encoded_string)

  @cache[key] ||= f.compute_width_of(encoded_string, options)

  length = @cache[key]

  character_count = @document.font.character_count(encoded_string)
  if character_count.positive?
    length += @document.character_spacing * (character_count - 1)
  end

  length
end