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 20 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 26 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 key = CacheEntry.new( f, options, string ) unless length = @cache[ key ] length = @cache[ key ] = f.compute_width_of(string, options) end length + (@document.character_spacing * @document.font.character_count(string)) end