class Prawn::FontMetricCache
Cache used internally by Prawn::Document
instances to calculate the width of various strings for layout purposes.
@private
Constants
- CacheEntry
Public Class Methods
new(document)
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# File lib/prawn/font_metric_cache.rb, line 18 def initialize(document) @document = document @cache = {} end
Public Instance Methods
width_of(string, options)
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# File lib/prawn/font_metric_cache.rb, line 24 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 = CacheEntry.new(f, 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