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# frozen_string_literal: true
require_relative '../table'
module TTFunk
class Table
# Maximum Profile (`maxp`) table
class Maxp < Table
# Default maximum levels of recursion.
DEFAULT_MAX_COMPONENT_DEPTH = 1
# Size of full table version 1.
MAX_V1_TABLE_LENGTH = 32
# Table version.
# @return [Integer]
attr_reader :version
# The number of glyphs in the font.
# @return [Integer]
attr_reader :num_glyphs
# Maximum points in a non-composite glyph.
# @return [Integer]
attr_reader :max_points
# Maximum contours in a non-composite glyph.
# @return [Integer]
attr_reader :max_contours
# Maximum points in a composite glyph.
# @return [Integer]
attr_reader :max_component_points
# Maximum contours in a composite glyph.
# @return [Integer]
attr_reader :max_component_contours
# Maximum zones.
# * 1 if instructions do not use the twilight zone (Z0)
# * 2 if instructions do use Z0
# @return [Integer]
attr_reader :max_zones
# Maximum points used in Z0.
# @return [Integer]
attr_reader :max_twilight_points
# Number of Storage Area locations.
# @return [Integer]
attr_reader :max_storage
# Number of FDEFs.
# @return [Integer]
attr_reader :max_function_defs
# Number of IDEFs.
# @return [Integer]
attr_reader :max_instruction_defs
# Maximum stack depth across Font Program, CVT Program and all glyph
# instructions.
# @return [Integer]
attr_reader :max_stack_elements
# Maximum byte count for glyph instructions.
# @return [Integer]
attr_reader :max_size_of_instructions
# Maximum number of components referenced at "top level" for any composite
# glyph.
# @return [Integer]
attr_reader :max_component_elements
# Maximum levels of recursion.
# @return [Integer]
attr_reader :max_component_depth
class << self
# Encode table.
#
# @param maxp [TTFunk::Table::Maxp]
# @param new2old_glyph [Hash{Integer => Integer}] keys are new glyph IDs, values
# are old glyph IDs.
# @return [String]
def encode(maxp, new2old_glyph)
''.b.tap do |table|
num_glyphs = new2old_glyph.length
table << [maxp.version, num_glyphs].pack('Nn')
if maxp.version == 0x10000
stats = stats_for(maxp, glyphs_from_ids(maxp, new2old_glyph.values))
table << [
stats[:max_points],
stats[:max_contours],
stats[:max_component_points],
stats[:max_component_contours],
# these all come from the fpgm and cvt tables, which
# we don't support at the moment
maxp.max_zones,
maxp.max_twilight_points,
maxp.max_storage,
maxp.max_function_defs,
maxp.max_instruction_defs,
maxp.max_stack_elements,
stats[:max_size_of_instructions],
stats[:max_component_elements],
stats[:max_component_depth],
].pack('n*')
end
end
end
private
def glyphs_from_ids(maxp, glyph_ids)
glyph_ids.each_with_object([]) do |glyph_id, ret|
if (glyph = maxp.file.glyph_outlines.for(glyph_id))
ret << glyph
end
end
end
def stats_for(maxp, glyphs)
stats_for_simple(maxp, glyphs)
.merge(stats_for_compound(maxp, glyphs))
.transform_values { |agg| agg.value_or(0) }
end
def stats_for_simple(_maxp, glyphs)
max_component_elements = Max.new
max_points = Max.new
max_contours = Max.new
max_size_of_instructions = Max.new
glyphs.each do |glyph|
if glyph.compound?
max_component_elements << glyph.glyph_ids.size
else
max_points << glyph.end_point_of_last_contour
max_contours << glyph.number_of_contours
max_size_of_instructions << glyph.instruction_length
end
end
{
max_component_elements: max_component_elements,
max_points: max_points,
max_contours: max_contours,
max_size_of_instructions: max_size_of_instructions,
}
end
def stats_for_compound(maxp, glyphs)
max_component_points = Max.new
max_component_depth = Max.new
max_component_contours = Max.new
glyphs.each do |glyph|
next unless glyph.compound?
stats = totals_for_compound(maxp, [glyph], 0)
max_component_points << stats[:total_points]
max_component_depth << stats[:max_depth]
max_component_contours << stats[:total_contours]
end
{
max_component_points: max_component_points,
max_component_depth: max_component_depth,
max_component_contours: max_component_contours,
}
end
def totals_for_compound(maxp, glyphs, depth)
total_points = Sum.new
total_contours = Sum.new
max_depth = Max.new(depth)
glyphs.each do |glyph|
if glyph.compound?
stats = totals_for_compound(maxp, glyphs_from_ids(maxp, glyph.glyph_ids), depth + 1)
total_points << stats[:total_points]
total_contours << stats[:total_contours]
max_depth << stats[:max_depth]
else
stats = stats_for_simple(maxp, [glyph])
total_points << stats[:max_points]
total_contours << stats[:max_contours]
end
end
{
total_points: total_points,
total_contours: total_contours,
max_depth: max_depth,
}
end
end
private
def parse!
@version, @num_glyphs = read(6, 'Nn')
if @version == 0x10000
@max_points, @max_contours, @max_component_points,
@max_component_contours, @max_zones, @max_twilight_points,
@max_storage, @max_function_defs, @max_instruction_defs,
@max_stack_elements, @max_size_of_instructions,
@max_component_elements = read(24, 'n*')
# a number of fonts omit these last two bytes for some reason,
# so we have to supply a default here to prevent nils
@max_component_depth =
if length == MAX_V1_TABLE_LENGTH
read(2, 'n').first
else
DEFAULT_MAX_COMPONENT_DEPTH
end
end
end
end
end
end
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