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
Source
# File lib/prawn/font_metric_cache.rb, line 11 def initialize(document) @document = document @cache = {} end
Public Instance Methods
Source
# File lib/prawn/font_metric_cache.rb, line 25 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, @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
Get width of string.
@param string [String] @param options [Hash{Symbol => any}] @option options :style [Symbol] @option options :size [Number] @option options :kerning [Boolean] (false) @return [Number]