class TTFunk::Table::Kern::Format0
Format 0 kerning subtable.
Attributes
Subtable attributes. @return [Hash{Symbol => any}]
Kerning pairs. @return [Hash{Array(Integer, Integer) => Integer}]
Public Class Methods
Source
# File lib/ttfunk/table/kern/format0.rb, line 21 def initialize(attributes = {}) @attributes = attributes num_pairs, *pairs = attributes.delete(:data).unpack('nx6n*') @pairs = {} num_pairs.times do |i| # sanity check, in case there's a bad length somewhere break if (i * 3) + 2 > pairs.length left = pairs[i * 3] right = pairs[(i * 3) + 1] value = to_signed(pairs[(i * 3) + 2]) @pairs[[left, right]] = value end end
@param attributes [Hash{Symbol => any}]
Public Instance Methods
Source
# File lib/ttfunk/table/kern/format0.rb, line 52 def cross_stream? @attributes[:cross] end
Is this cross-stream kerning? @return [Boolean]
Source
# File lib/ttfunk/table/kern/format0.rb, line 46 def horizontal? !vertical? end
Is this horizontal kerning? @return [Boolean]
Source
# File lib/ttfunk/table/kern/format0.rb, line 61 def recode(mapping) subset = [] pairs.each do |(left, right), value| if mapping[left] && mapping[right] subset << [mapping[left], mapping[right], value] end end return if subset.empty? num_pairs = subset.length search_range = 2 * (2**Integer(Math.log(num_pairs) / Math.log(2))) entry_selector = Integer(Math.log(search_range / 2) / Math.log(2)) range_shift = (2 * num_pairs) - search_range [ attributes[:version], (num_pairs * 6) + 14, attributes[:coverage], num_pairs, search_range, entry_selector, range_shift, subset, ].flatten.pack('n*') end
Recode this subtable using the specified mapping.
@param mapping [Hash{Integer => Integer}] keys are new glyph IDs,
values are old glyph IDs
@return [String]
Source
# File lib/ttfunk/table/kern/format0.rb, line 40 def vertical? @attributes[:vertical] end
Is this vertical kerning? @return [Boolean]