class Prawn::Fonts::TTF

TrueType font.

@note You shouldn’t use this class directly.

Attributes

subsets [R]

ttf [R]

TTFunk font. @return [TTFunk::File]

Public Class Methods

new (document, name, options = {})

Source

# File lib/prawn/fonts/ttf.rb, line 134
def initialize(document, name, options = {})
  super

  @ttf = read_ttf_file
  @subsets =
    if full_font_embedding
      FullFontSubsetsCollection.new(@ttf)
    else
      TTFunk::SubsetCollection.new(@ttf)
    end
  @italic_angle = nil

  @attributes = {}
  @bounding_boxes = {}
  @char_widths = {}
  @has_kerning_data = @ttf.kerning.exists? && @ttf.kerning.tables.any?

  @ascender = Integer(@ttf.ascent * scale_factor)
  @descender = Integer(@ttf.descent * scale_factor)
  @line_gap = Integer(@ttf.line_gap * scale_factor)
end

@param document [Prawn::Document] @param name [String] font file path @param options [Hash] @option options :family [String] @option options :style [Symbol]

Calls superclass method Prawn::Font::new

Public Instance Methods

basename ()

Source

# File lib/prawn/fonts/ttf.rb, line 240
def basename
  @basename ||= @ttf.name.postscript_name
end

Base name of the font.

@return [String]

bbox ()

Source

# File lib/prawn/fonts/ttf.rb, line 184
def bbox
  @bbox ||= @ttf.bbox.map { |i| Integer(i * scale_factor) }
end

The font bbox.

@return [Array(Number, Number, Number, Number)]

cap_height ()

Source

# File lib/prawn/fonts/ttf.rb, line 272
def cap_height
  @cap_height ||=
    begin
      height = (@ttf.os2.exists? && @ttf.os2.cap_height) || 0
      height.zero? ? @ascender : height
    end
end

@private @return [Number]

character_count (str)

Source

# File lib/prawn/fonts/ttf.rb, line 354
def character_count(str)
  str.length
end

Returns the number of characters in ‘str` (a UTF-8-encoded string).

@param str [String] @return [Integer]

compute_width_of (string, options = {})

Source

# File lib/prawn/fonts/ttf.rb, line 164
def compute_width_of(string, options = {})
  scale = (options[:size] || size) / 1000.0
  if options[:kerning]
    kern(string).reduce(0) { |s, r|
      if r.is_a?(Numeric)
        s - r
      else
        r.reduce(s) { |a, e| a + character_width_by_code(e) }
      end
    } * scale
  else
    string.codepoints.reduce(0) { |s, r|
      s + character_width_by_code(r)
    } * scale
  end
end

Compute width of a string at the specified size, optionally with kerning applied.

@param string [String] must be encoded as UTF-8 @param options [Hash{Symbol => any}] @option options :size [Number] @option options :kerning [Boolean] (false) @return [Number]

encode_text (text, options = {})

Source

# File lib/prawn/fonts/ttf.rb, line 204
def encode_text(text, options = {})
  text = text.chomp

  if options[:kerning]
    last_subset = nil
    kern(text).reduce([]) do |result, element|
      if element.is_a?(Numeric)
        unless result.last[1].is_a?(Array)
          result.last[1] = [result.last[1]]
        end
        result.last[1] << element
        result
      else
        encoded = @subsets.encode(element)

        if encoded.first[0] == last_subset
          result.last[1] << encoded.first[1]
          encoded.shift
        end

        if encoded.any?
          last_subset = encoded.last[0]
          result + encoded
        else
          result
        end
      end
    end
  else
    @subsets.encode(text.unpack('U*'))
  end
end

Perform any changes to the string that need to happen before it is rendered to the canvas. Returns an array of subset “chunks”, where the even-numbered indices are the font subset number, and the following entry element is either a string or an array (for kerned text).

@param text [String] must be in UTF-8 encoding @param options [Hash{Symbol => any}] @option options :kerning [Boolean] @return [Array<Array(0, (String, Array)>]

family_class ()

Source

# File lib/prawn/fonts/ttf.rb, line 290
def family_class
  @family_class ||= ((@ttf.os2.exists? && @ttf.os2.family_class) || 0) >> 8
end

@private @return [Number]

glyph_present? (char)

Source

# File lib/prawn/fonts/ttf.rb, line 345
def glyph_present?(char)
  code = char.codepoints.first
  cmap[code].positive?
end

Does this font has a glyph for the character?

@param char [String] @return [Boolean]

has_kerning_data? ()

Source

# File lib/prawn/fonts/ttf.rb, line 191
def has_kerning_data? # rubocop: disable Naming/PredicateName
  @has_kerning_data
end

Does this font contain kerning data.

@return [Boolean]

italic_angle ()

Source

# File lib/prawn/fonts/ttf.rb, line 254
def italic_angle
  return @italic_angle if @italic_angle

  if @ttf.postscript.exists?
    raw = @ttf.postscript.italic_angle
    hi = raw >> 16
    low = raw & 0xFF
    hi = -((hi ^ 0xFFFF) + 1) if hi & 0x8000 != 0
    @italic_angle = Float("#{hi}.#{low}")
  else
    @italic_angle = 0
  end

  @italic_angle
end

@private @return [Number]

normalize_encoding (text)

Source

# File lib/prawn/fonts/ttf.rb, line 325
def normalize_encoding(text)
  text.encode(::Encoding::UTF_8)
rescue StandardError
  raise Prawn::Errors::IncompatibleStringEncoding,
    "Encoding #{text.encoding} can not be transparently converted to UTF-8. " \
      'Please ensure the encoding of the string you are attempting to use is set correctly'
end

Normlize text to a compatible encoding.

@param text [String] @return [String]

pdf_flags ()

Source

# File lib/prawn/fonts/ttf.rb, line 308
def pdf_flags
  @pdf_flags ||=
    begin
      flags = 0
      flags |= 0x0001 if @ttf.postscript.fixed_pitch?
      flags |= 0x0002 if serif?
      flags |= 0x0008 if script?
      flags |= 0x0040 if italic_angle != 0
      # Assume the font contains at least some non-latin characters
      flags | 0x0004
    end
end

@private @return [Integer]

script? ()

Source

# File lib/prawn/fonts/ttf.rb, line 302
def script?
  @script ||= family_class == 10
end

@private @return [Boolean]

serif? ()

Source

# File lib/prawn/fonts/ttf.rb, line 296
def serif?
  @serif ||= [1, 2, 3, 4, 5, 7].include?(family_class)
end

@private @return [Boolean]

stem_v ()

Source

# File lib/prawn/fonts/ttf.rb, line 248
def stem_v
  0
end

@devnote not sure how to compute this for true-type fonts…

@private @return [Number]

to_utf8 (text)

Source

# File lib/prawn/fonts/ttf.rb, line 337
def to_utf8(text)
  text.encode('UTF-8')
end

Encode text to UTF-8.

@param text [String] @return [String]

unicode? ()

Source

# File lib/prawn/fonts/ttf.rb, line 63
def unicode?
  true
end

Does this font support Unicode?

@return [true]

x_height ()

Source

# File lib/prawn/fonts/ttf.rb, line 282
def x_height
  # FIXME: seems like if os2 table doesn't exist, we could
  # just find the height of the lower-case 'x' glyph?
  (@ttf.os2.exists? && @ttf.os2.x_height) || 0
end

@private @return [number]