Module: Acrofill::Metrics

Defined in:

lib/acrofill/metrics.rb

Overview

Glyph widths (1/1000 em) for the standard-14 text fonts, indexed by WinAnsiEncoding code minus 32 (appearance streams are written as Windows-1252 bytes against a /WinAnsiEncoding font, so the byte emitted is the byte measured). Extracted from Adobe AFM metrics.

Only six tables are stored: the oblique cuts of Helvetica have the same widths as the upright face, and the whole Courier family is monospaced. #widths_for maps every other BaseFont name onto them.

Constant Summary

DEFAULT_WIDTH =

556

COURIER_WIDTH =

600

FIRST_CODE =

32

LAST_CODE =

255

WINDOWS_1252 =

Encoding::Windows_1252

TIMES =

Bold/italic Times cuts, indexed by bold + 2 * italic.

%w[Times-Roman Times-Bold Times-Italic Times-BoldItalic].freeze

SERIF =

Family and weight hints for BaseFont names outside the standard 14.

/times|roman|serif|georgia|garamond/

SANS =

/sans/

FIXED =

/courier|mono/

BOLD =

/bold|black|heavy/

ITALIC =

/italic|oblique/

WIDTHS =

{
  'Helvetica' => [
    278, 278, 355, 556, 556, 889, 667, 191, 333, 333, 389, 584, 278, 333, 278, 278, 556,
    556, 556, 556, 556, 556, 556, 556, 556, 556, 278, 278, 584, 584, 584, 556, 1015, 667,
    667, 722, 722, 667, 611, 778, 722, 278, 500, 667, 556, 833, 722, 778, 667, 778, 722,
    667, 611, 722, 667, 944, 667, 667, 611, 278, 278, 278, 469, 556, 333, 556, 556, 500,
    556, 556, 278, 556, 556, 222, 222, 500, 222, 833, 556, 556, 556, 556, 333, 500, 278,
    556, 500, 722, 500, 500, 500, 334, 260, 334, 584, nil, 556, nil, 222, 556, 333, 1000,
    556, 556, 333, 1000, 667, 333, 1000, nil, 611, nil, nil, 222, 222, 333, 333, 350, 556,
    1000, 333, 1000, 500, 333, 944, nil, 500, 667, 278, 333, 556, 556, 556, 556, 260, 556,
    333, 737, 370, 556, 584, 333, 737, 333, 400, 584, 333, 333, 333, 556, 537, 278, 333,
    333, 365, 556, 834, 834, 834, 611, 667, 667, 667, 667, 667, 667, 1000, 722, 667, 667,
    667, 667, 278, 278, 278, 278, 722, 722, 778, 778, 778, 778, 778, 584, 778, 722, 722,
    722, 722, 667, 667, 611, 556, 556, 556, 556, 556, 556, 889, 500, 556, 556, 556, 556,
    278, 278, 278, 278, 556, 556, 556, 556, 556, 556, 556, 584, 611, 556, 556, 556, 556,
    500, 556, 500
  ].freeze,
  'Helvetica-Bold' => [
    278, 333, 474, 556, 556, 889, 722, 238, 333, 333, 389, 584, 278, 333, 278, 278, 556,
    556, 556, 556, 556, 556, 556, 556, 556, 556, 333, 333, 584, 584, 584, 611, 975, 722,
    722, 722, 722, 667, 611, 778, 722, 278, 556, 722, 611, 833, 722, 778, 667, 778, 722,
    667, 611, 722, 667, 944, 667, 667, 611, 333, 278, 333, 584, 556, 333, 556, 611, 556,
    611, 556, 333, 611, 611, 278, 278, 556, 278, 889, 611, 611, 611, 611, 389, 556, 333,
    611, 556, 778, 556, 556, 500, 389, 280, 389, 584, nil, 556, nil, 278, 556, 500, 1000,
    556, 556, 333, 1000, 667, 333, 1000, nil, 611, nil, nil, 278, 278, 500, 500, 350, 556,
    1000, 333, 1000, 556, 333, 944, nil, 500, 667, 278, 333, 556, 556, 556, 556, 280, 556,
    333, 737, 370, 556, 584, 333, 737, 333, 400, 584, 333, 333, 333, 611, 556, 278, 333,
    333, 365, 556, 834, 834, 834, 611, 722, 722, 722, 722, 722, 722, 1000, 722, 667, 667,
    667, 667, 278, 278, 278, 278, 722, 722, 778, 778, 778, 778, 778, 584, 778, 722, 722,
    722, 722, 667, 667, 611, 556, 556, 556, 556, 556, 556, 889, 556, 556, 556, 556, 556,
    278, 278, 278, 278, 611, 611, 611, 611, 611, 611, 611, 584, 611, 611, 611, 611, 611,
    556, 611, 556
  ].freeze,
  'Times-Roman' => [
    250, 333, 408, 500, 500, 833, 778, 180, 333, 333, 500, 564, 250, 333, 250, 278, 500,
    500, 500, 500, 500, 500, 500, 500, 500, 500, 278, 278, 564, 564, 564, 444, 921, 722,
    667, 667, 722, 611, 556, 722, 722, 333, 389, 722, 611, 889, 722, 722, 556, 722, 667,
    556, 611, 722, 722, 944, 722, 722, 611, 333, 278, 333, 469, 500, 333, 444, 500, 444,
    500, 444, 333, 500, 500, 278, 278, 500, 278, 778, 500, 500, 500, 500, 333, 389, 278,
    500, 500, 722, 500, 500, 444, 480, 200, 480, 541, nil, 500, nil, 333, 500, 444, 1000,
    500, 500, 333, 1000, 556, 333, 889, nil, 611, nil, nil, 333, 333, 444, 444, 350, 500,
    1000, 333, 980, 389, 333, 722, nil, 444, 722, 250, 333, 500, 500, 500, 500, 200, 500,
    333, 760, 276, 500, 564, 333, 760, 333, 400, 564, 300, 300, 333, 500, 453, 250, 333,
    300, 310, 500, 750, 750, 750, 444, 722, 722, 722, 722, 722, 722, 889, 667, 611, 611,
    611, 611, 333, 333, 333, 333, 722, 722, 722, 722, 722, 722, 722, 564, 722, 722, 722,
    722, 722, 722, 556, 500, 444, 444, 444, 444, 444, 444, 667, 444, 444, 444, 444, 444,
    278, 278, 278, 278, 500, 500, 500, 500, 500, 500, 500, 564, 500, 500, 500, 500, 500,
    500, 500, 500
  ].freeze,
  'Times-Bold' => [
    250, 333, 555, 500, 500, 1000, 833, 278, 333, 333, 500, 570, 250, 333, 250, 278, 500,
    500, 500, 500, 500, 500, 500, 500, 500, 500, 333, 333, 570, 570, 570, 500, 930, 722,
    667, 722, 722, 667, 611, 778, 778, 389, 500, 778, 667, 944, 722, 778, 611, 778, 722,
    556, 667, 722, 722, 1000, 722, 722, 667, 333, 278, 333, 581, 500, 333, 500, 556, 444,
    556, 444, 333, 500, 556, 278, 333, 556, 278, 833, 556, 500, 556, 556, 444, 389, 333,
    556, 500, 722, 500, 500, 444, 394, 220, 394, 520, nil, 500, nil, 333, 500, 500, 1000,
    500, 500, 333, 1000, 556, 333, 1000, nil, 667, nil, nil, 333, 333, 500, 500, 350, 500,
    1000, 333, 1000, 389, 333, 722, nil, 444, 722, 250, 333, 500, 500, 500, 500, 220, 500,
    333, 747, 300, 500, 570, 333, 747, 333, 400, 570, 300, 300, 333, 556, 540, 250, 333,
    300, 330, 500, 750, 750, 750, 500, 722, 722, 722, 722, 722, 722, 1000, 722, 667, 667,
    667, 667, 389, 389, 389, 389, 722, 722, 778, 778, 778, 778, 778, 570, 778, 722, 722,
    722, 722, 722, 611, 556, 500, 500, 500, 500, 500, 500, 722, 444, 444, 444, 444, 444,
    278, 278, 278, 278, 500, 556, 500, 500, 500, 500, 500, 570, 500, 556, 556, 556, 556,
    500, 556, 500
  ].freeze,
  'Times-Italic' => [
    250, 333, 420, 500, 500, 833, 778, 214, 333, 333, 500, 675, 250, 333, 250, 278, 500,
    500, 500, 500, 500, 500, 500, 500, 500, 500, 333, 333, 675, 675, 675, 500, 920, 611,
    611, 667, 722, 611, 611, 722, 722, 333, 444, 667, 556, 833, 667, 722, 611, 722, 611,
    500, 556, 722, 611, 833, 611, 556, 556, 389, 278, 389, 422, 500, 333, 500, 500, 444,
    500, 444, 278, 500, 500, 278, 278, 444, 278, 722, 500, 500, 500, 500, 389, 389, 278,
    500, 444, 667, 444, 444, 389, 400, 275, 400, 541, nil, 500, nil, 333, 500, 556, 889,
    500, 500, 333, 1000, 500, 333, 944, nil, 556, nil, nil, 333, 333, 556, 556, 350, 500,
    889, 333, 980, 389, 333, 667, nil, 389, 556, 250, 389, 500, 500, 500, 500, 275, 500,
    333, 760, 276, 500, 675, 333, 760, 333, 400, 675, 300, 300, 333, 500, 523, 250, 333,
    300, 310, 500, 750, 750, 750, 500, 611, 611, 611, 611, 611, 611, 889, 667, 611, 611,
    611, 611, 333, 333, 333, 333, 722, 667, 722, 722, 722, 722, 722, 675, 722, 722, 722,
    722, 722, 556, 611, 500, 500, 500, 500, 500, 500, 500, 667, 444, 444, 444, 444, 444,
    278, 278, 278, 278, 500, 500, 500, 500, 500, 500, 500, 675, 500, 500, 500, 500, 500,
    444, 500, 444
  ].freeze,
  'Times-BoldItalic' => [
    250, 389, 555, 500, 500, 833, 778, 278, 333, 333, 500, 570, 250, 333, 250, 278, 500,
    500, 500, 500, 500, 500, 500, 500, 500, 500, 333, 333, 570, 570, 570, 500, 832, 667,
    667, 667, 722, 667, 667, 722, 778, 389, 500, 667, 611, 889, 722, 722, 611, 722, 667,
    556, 611, 722, 667, 889, 667, 611, 611, 333, 278, 333, 570, 500, 333, 500, 500, 444,
    500, 444, 333, 500, 556, 278, 278, 500, 278, 778, 556, 500, 500, 500, 389, 389, 278,
    556, 444, 667, 500, 444, 389, 348, 220, 348, 570, nil, 500, nil, 333, 500, 500, 1000,
    500, 500, 333, 1000, 556, 333, 944, nil, 611, nil, nil, 333, 333, 500, 500, 350, 500,
    1000, 333, 1000, 389, 333, 722, nil, 389, 611, 250, 389, 500, 500, 500, 500, 220, 500,
    333, 747, 266, 500, 606, 333, 747, 333, 400, 570, 300, 300, 333, 576, 500, 250, 333,
    300, 300, 500, 750, 750, 750, 500, 667, 667, 667, 667, 667, 667, 944, 667, 667, 667,
    667, 667, 389, 389, 389, 389, 722, 722, 722, 722, 722, 722, 722, 570, 722, 722, 722,
    722, 722, 611, 611, 500, 500, 500, 500, 500, 500, 500, 722, 444, 444, 444, 444, 444,
    278, 278, 278, 278, 500, 556, 500, 500, 500, 500, 500, 570, 500, 556, 556, 556, 556,
    444, 500, 444
  ].freeze,
  'Courier' => Array.new(LAST_CODE - FIRST_CODE + 1, COURIER_WIDTH).freeze
}.freeze

Class Method Summary

• .string_width(str, widths, size) ⇒ Object

  Width of str at size points.

• .widths_for(base_font) ⇒ Object

  The width table for a BaseFont name.

Class Method Details

.string_width(str, widths, size) ⇒ Object

Width of str at size points. widths is a table from #widths_for, or a BaseFont name (resolved here, at the cost of the lookup).

# File 'lib/acrofill/metrics.rb', line 130

def self.string_width(str, widths, size)
  widths = widths_for(widths) unless widths.is_a?(Array)
  str = to_win_ansi(str)
  units = str.each_byte.sum do |code|
    (code >= FIRST_CODE && widths[code - FIRST_CODE]) || DEFAULT_WIDTH
  end
  units * size / 1000.0
end

.widths_for(base_font) ⇒ Object

The width table for a BaseFont name. Standard-14 names hit the table directly; anything else (ArialMT, TimesNewRomanPS-BoldMT, a template's embedded face) is classified by family and weight, which is far closer than measuring everything as Helvetica.

# File 'lib/acrofill/metrics.rb', line 143

def self.widths_for(base_font)
  name = base_font.to_s
  return WIDTHS[name] if WIDTHS.key?(name)

  lower = name.downcase
  return WIDTHS['Courier'] if FIXED.match?(lower)
  return WIDTHS[TIMES[weight_index(lower)]] if serif?(lower)

  WIDTHS[BOLD.match?(lower) ? 'Helvetica-Bold' : 'Helvetica']
end