/*
 * Copyright © 2018  Ebrahim Byagowi
 *
 *  This is part of HarfBuzz, a text shaping library.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and its documentation for any purpose, provided that the
 * above copyright notice and the following two paragraphs appear in
 * all copies of this software.
 *
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 */

#ifndef HB_AAT_H_IN
#error "Include <hb-aat.h> instead."
#endif

#ifndef HB_AAT_LAYOUT_H
#define HB_AAT_LAYOUT_H

#include "hb.h"

#include "hb-ot.h"

HB_BEGIN_DECLS

/**
 * hb_aat_layout_feature_type_t:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_INVALID: Initial, unset feature type
 * @HB_AAT_LAYOUT_FEATURE_TYPE_ALL_TYPOGRAPHIC:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_CURISVE_CONNECTION:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_LETTER_CASE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_SUBSTITUTION:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_LINGUISTIC_REARRANGEMENT:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_SPACING:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_SMART_SWASH_TYPE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_DIACRITICS_TYPE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_POSITION:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_FRACTIONS:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_OVERLAPPING_CHARACTERS_TYPE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_ORNAMENT_SETS_TYPE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_ALTERNATIVES:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_DESIGN_COMPLEXITY_TYPE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_STYLE_OPTIONS:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_CASE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_TRANSLITERATION:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_ANNOTATION_TYPE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_KANA_SPACING_TYPE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_SPACING_TYPE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_UNICODE_DECOMPOSITION_TYPE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_RUBY_KANA:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_CJK_SYMBOL_ALTERNATIVES_TYPE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_ALTERNATIVES_TYPE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_CJK_VERTICAL_ROMAN_PLACEMENT_TYPE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_ITALIC_CJK_ROMAN:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_CASE_SENSITIVE_LAYOUT:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_ALTERNATE_KANA:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_CONTEXTUAL_ALTERNATIVES:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_LOWER_CASE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_UPPER_CASE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_LANGUAGE_TAG_TYPE:
 * @HB_AAT_LAYOUT_FEATURE_TYPE_CJK_ROMAN_SPACING_TYPE:
 *
 * The possible feature types defined for AAT shaping.
 *
 * Since: 2.2.0
 */
typedef enum
{
  HB_AAT_LAYOUT_FEATURE_TYPE_INVALID				= 0xFFFF,

  HB_AAT_LAYOUT_FEATURE_TYPE_ALL_TYPOGRAPHIC			= 0,
  HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES				= 1,
  HB_AAT_LAYOUT_FEATURE_TYPE_CURISVE_CONNECTION			= 2,
  HB_AAT_LAYOUT_FEATURE_TYPE_LETTER_CASE			= 3,
  HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_SUBSTITUTION		= 4,
  HB_AAT_LAYOUT_FEATURE_TYPE_LINGUISTIC_REARRANGEMENT		= 5,
  HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_SPACING			= 6,
  HB_AAT_LAYOUT_FEATURE_TYPE_SMART_SWASH_TYPE			= 8,
  HB_AAT_LAYOUT_FEATURE_TYPE_DIACRITICS_TYPE			= 9,
  HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_POSITION			= 10,
  HB_AAT_LAYOUT_FEATURE_TYPE_FRACTIONS				= 11,
  HB_AAT_LAYOUT_FEATURE_TYPE_OVERLAPPING_CHARACTERS_TYPE	= 13,
  HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS			= 14,
  HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS		= 15,
  HB_AAT_LAYOUT_FEATURE_TYPE_ORNAMENT_SETS_TYPE			= 16,
  HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_ALTERNATIVES		= 17,
  HB_AAT_LAYOUT_FEATURE_TYPE_DESIGN_COMPLEXITY_TYPE		= 18,
  HB_AAT_LAYOUT_FEATURE_TYPE_STYLE_OPTIONS			= 19,
  HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE			= 20,
  HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_CASE			= 21,
  HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING			= 22,
  HB_AAT_LAYOUT_FEATURE_TYPE_TRANSLITERATION			= 23,
  HB_AAT_LAYOUT_FEATURE_TYPE_ANNOTATION_TYPE			= 24,
  HB_AAT_LAYOUT_FEATURE_TYPE_KANA_SPACING_TYPE			= 25,
  HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_SPACING_TYPE		= 26,
  HB_AAT_LAYOUT_FEATURE_TYPE_UNICODE_DECOMPOSITION_TYPE		= 27,
  HB_AAT_LAYOUT_FEATURE_TYPE_RUBY_KANA				= 28,
  HB_AAT_LAYOUT_FEATURE_TYPE_CJK_SYMBOL_ALTERNATIVES_TYPE	= 29,
  HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_ALTERNATIVES_TYPE	= 30,
  HB_AAT_LAYOUT_FEATURE_TYPE_CJK_VERTICAL_ROMAN_PLACEMENT_TYPE	= 31,
  HB_AAT_LAYOUT_FEATURE_TYPE_ITALIC_CJK_ROMAN			= 32,
  HB_AAT_LAYOUT_FEATURE_TYPE_CASE_SENSITIVE_LAYOUT		= 33,
  HB_AAT_LAYOUT_FEATURE_TYPE_ALTERNATE_KANA			= 34,
  HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES		= 35,
  HB_AAT_LAYOUT_FEATURE_TYPE_CONTEXTUAL_ALTERNATIVES		= 36,
  HB_AAT_LAYOUT_FEATURE_TYPE_LOWER_CASE				= 37,
  HB_AAT_LAYOUT_FEATURE_TYPE_UPPER_CASE				= 38,
  HB_AAT_LAYOUT_FEATURE_TYPE_LANGUAGE_TAG_TYPE			= 39,
  HB_AAT_LAYOUT_FEATURE_TYPE_CJK_ROMAN_SPACING_TYPE		= 103,

  /*< private >*/
  _HB_AAT_LAYOUT_FEATURE_TYPE_MAX_VALUE = HB_TAG_MAX_SIGNED /*< skip >*/
} hb_aat_layout_feature_type_t;

/**
 * hb_aat_layout_feature_selector_t:
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_INVALID: Initial, unset feature selector
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ALL_TYPE_FEATURES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_ALL_TYPOGRAPHIC
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ALL_TYPE_FEATURES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_ALL_TYPOGRAPHIC
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_REQUIRED_LIGATURES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_REQUIRED_LIGATURES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_COMMON_LIGATURES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_COMMON_LIGATURES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_RARE_LIGATURES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_RARE_LIGATURES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_LOGOS_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_LOGOS_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_REBUS_PICTURES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_REBUS_PICTURES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DIPHTHONG_LIGATURES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DIPHTHONG_LIGATURES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SQUARED_LIGATURES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SQUARED_LIGATURES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ABBREV_SQUARED_LIGATURES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ABBREV_SQUARED_LIGATURES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SYMBOL_LIGATURES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SYMBOL_LIGATURES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CONTEXTUAL_LIGATURES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CONTEXTUAL_LIGATURES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HISTORICAL_LIGATURES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HISTORICAL_LIGATURES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_UNCONNECTED: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_PARTIALLY_CONNECTED: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CURSIVE: for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_UPPER_AND_LOWER_CASE: Deprecated
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ALL_CAPS: Deprecated
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ALL_LOWER_CASE: Deprecated
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SMALL_CAPS: Deprecated
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_INITIAL_CAPS: Deprecated
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_INITIAL_CAPS_AND_SMALL_CAPS: Deprecated
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SUBSTITUTE_VERTICAL_FORMS_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_SUBSTITUTION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SUBSTITUTE_VERTICAL_FORMS_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_SUBSTITUTION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_LINGUISTIC_REARRANGEMENT_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_LINGUISTIC_REARRANGEMENT
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_LINGUISTIC_REARRANGEMENT_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_LINGUISTIC_REARRANGEMENT
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_MONOSPACED_NUMBERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_SPACING
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_PROPORTIONAL_NUMBERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_SPACING
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_THIRD_WIDTH_NUMBERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_SPACING
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_QUARTER_WIDTH_NUMBERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_SPACING
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_WORD_INITIAL_SWASHES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_SMART_SWASH_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_WORD_INITIAL_SWASHES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_SMART_SWASH_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_WORD_FINAL_SWASHES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_SMART_SWASH_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_WORD_FINAL_SWASHES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_SMART_SWASH_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_LINE_INITIAL_SWASHES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_SMART_SWASH_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_LINE_INITIAL_SWASHES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_SMART_SWASH_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_LINE_FINAL_SWASHES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_SMART_SWASH_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_LINE_FINAL_SWASHES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_SMART_SWASH_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NON_FINAL_SWASHES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_SMART_SWASH_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NON_FINAL_SWASHES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_SMART_SWASH_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SHOW_DIACRITICS: for #HB_AAT_LAYOUT_FEATURE_TYPE_DIACRITICS_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HIDE_DIACRITICS: for #HB_AAT_LAYOUT_FEATURE_TYPE_DIACRITICS_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DECOMPOSE_DIACRITICS: for #HB_AAT_LAYOUT_FEATURE_TYPE_DIACRITICS_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NORMAL_POSITION: for #HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_POSITION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SUPERIORS: for #HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_POSITION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_INFERIORS: for #HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_POSITION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ORDINALS: for #HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_POSITION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SCIENTIFIC_INFERIORS: for #HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_POSITION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_FRACTIONS: for #HB_AAT_LAYOUT_FEATURE_TYPE_FRACTIONS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_VERTICAL_FRACTIONS: for #HB_AAT_LAYOUT_FEATURE_TYPE_FRACTIONS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DIAGONAL_FRACTIONS: for #HB_AAT_LAYOUT_FEATURE_TYPE_FRACTIONS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_PREVENT_OVERLAP_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_OVERLAPPING_CHARACTERS_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_PREVENT_OVERLAP_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_OVERLAPPING_CHARACTERS_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HYPHENS_TO_EM_DASH_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HYPHENS_TO_EM_DASH_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HYPHEN_TO_EN_DASH_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HYPHEN_TO_EN_DASH_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SLASHED_ZERO_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SLASHED_ZERO_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_FORM_INTERROBANG_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_FORM_INTERROBANG_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SMART_QUOTES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SMART_QUOTES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_PERIODS_TO_ELLIPSIS_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_PERIODS_TO_ELLIPSIS_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HYPHEN_TO_MINUS_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HYPHEN_TO_MINUS_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ASTERISK_TO_MULTIPLY_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ASTERISK_TO_MULTIPLY_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SLASH_TO_DIVIDE_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SLASH_TO_DIVIDE_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_INEQUALITY_LIGATURES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_INEQUALITY_LIGATURES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_EXPONENTS_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_EXPONENTS_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_MATHEMATICAL_GREEK_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_MATHEMATICAL_GREEK_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_ORNAMENTS: for #HB_AAT_LAYOUT_FEATURE_TYPE_ORNAMENT_SETS_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DINGBATS: for #HB_AAT_LAYOUT_FEATURE_TYPE_ORNAMENT_SETS_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_PI_CHARACTERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_ORNAMENT_SETS_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_FLEURONS: for #HB_AAT_LAYOUT_FEATURE_TYPE_ORNAMENT_SETS_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DECORATIVE_BORDERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_ORNAMENT_SETS_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_INTERNATIONAL_SYMBOLS: for #HB_AAT_LAYOUT_FEATURE_TYPE_ORNAMENT_SETS_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_MATH_SYMBOLS: for #HB_AAT_LAYOUT_FEATURE_TYPE_ORNAMENT_SETS_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_ALTERNATES: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DESIGN_LEVEL1: for #HB_AAT_LAYOUT_FEATURE_TYPE_DESIGN_COMPLEXITY_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DESIGN_LEVEL2: for #HB_AAT_LAYOUT_FEATURE_TYPE_DESIGN_COMPLEXITY_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DESIGN_LEVEL3: for #HB_AAT_LAYOUT_FEATURE_TYPE_DESIGN_COMPLEXITY_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DESIGN_LEVEL4: for #HB_AAT_LAYOUT_FEATURE_TYPE_DESIGN_COMPLEXITY_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DESIGN_LEVEL5: for #HB_AAT_LAYOUT_FEATURE_TYPE_DESIGN_COMPLEXITY_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_STYLE_OPTIONS: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLE_OPTIONS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DISPLAY_TEXT: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLE_OPTIONS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ENGRAVED_TEXT: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLE_OPTIONS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ILLUMINATED_CAPS: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLE_OPTIONS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_TITLING_CAPS: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLE_OPTIONS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_TALL_CAPS: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLE_OPTIONS
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_TRADITIONAL_CHARACTERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SIMPLIFIED_CHARACTERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_JIS1978_CHARACTERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_JIS1983_CHARACTERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_JIS1990_CHARACTERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_TRADITIONAL_ALT_ONE: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_TRADITIONAL_ALT_TWO: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_TRADITIONAL_ALT_THREE: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_TRADITIONAL_ALT_FOUR: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_TRADITIONAL_ALT_FIVE: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_EXPERT_CHARACTERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_JIS2004_CHARACTERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HOJO_CHARACTERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NLCCHARACTERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_TRADITIONAL_NAMES_CHARACTERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_LOWER_CASE_NUMBERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_CASE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_UPPER_CASE_NUMBERS: for #HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_CASE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_PROPORTIONAL_TEXT: for #HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_MONOSPACED_TEXT: for #HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HALF_WIDTH_TEXT: for #HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_THIRD_WIDTH_TEXT: for #HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_QUARTER_WIDTH_TEXT: for #HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ALT_PROPORTIONAL_TEXT: for #HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ALT_HALF_WIDTH_TEXT: for #HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_TRANSLITERATION: for #HB_AAT_LAYOUT_FEATURE_TYPE_TRANSLITERATION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HANJA_TO_HANGUL: for #HB_AAT_LAYOUT_FEATURE_TYPE_TRANSLITERATION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HIRAGANA_TO_KATAKANA: for #HB_AAT_LAYOUT_FEATURE_TYPE_TRANSLITERATION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_KATAKANA_TO_HIRAGANA: for #HB_AAT_LAYOUT_FEATURE_TYPE_TRANSLITERATION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_KANA_TO_ROMANIZATION: for #HB_AAT_LAYOUT_FEATURE_TYPE_TRANSLITERATION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ROMANIZATION_TO_HIRAGANA: for #HB_AAT_LAYOUT_FEATURE_TYPE_TRANSLITERATION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ROMANIZATION_TO_KATAKANA: for #HB_AAT_LAYOUT_FEATURE_TYPE_TRANSLITERATION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HANJA_TO_HANGUL_ALT_ONE: for #HB_AAT_LAYOUT_FEATURE_TYPE_TRANSLITERATION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HANJA_TO_HANGUL_ALT_TWO: for #HB_AAT_LAYOUT_FEATURE_TYPE_TRANSLITERATION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HANJA_TO_HANGUL_ALT_THREE: for #HB_AAT_LAYOUT_FEATURE_TYPE_TRANSLITERATION
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_ANNOTATION: for #HB_AAT_LAYOUT_FEATURE_TYPE_ANNOTATION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_BOX_ANNOTATION: for #HB_AAT_LAYOUT_FEATURE_TYPE_ANNOTATION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ROUNDED_BOX_ANNOTATION: for #HB_AAT_LAYOUT_FEATURE_TYPE_ANNOTATION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CIRCLE_ANNOTATION: for #HB_AAT_LAYOUT_FEATURE_TYPE_ANNOTATION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_INVERTED_CIRCLE_ANNOTATION: for #HB_AAT_LAYOUT_FEATURE_TYPE_ANNOTATION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_PARENTHESIS_ANNOTATION: for #HB_AAT_LAYOUT_FEATURE_TYPE_ANNOTATION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_PERIOD_ANNOTATION: for #HB_AAT_LAYOUT_FEATURE_TYPE_ANNOTATION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ROMAN_NUMERAL_ANNOTATION: for #HB_AAT_LAYOUT_FEATURE_TYPE_ANNOTATION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DIAMOND_ANNOTATION: for #HB_AAT_LAYOUT_FEATURE_TYPE_ANNOTATION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_INVERTED_BOX_ANNOTATION: for #HB_AAT_LAYOUT_FEATURE_TYPE_ANNOTATION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_INVERTED_ROUNDED_BOX_ANNOTATION: for #HB_AAT_LAYOUT_FEATURE_TYPE_ANNOTATION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_FULL_WIDTH_KANA: for #HB_AAT_LAYOUT_FEATURE_TYPE_KANA_SPACING_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_PROPORTIONAL_KANA: for #HB_AAT_LAYOUT_FEATURE_TYPE_KANA_SPACING_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_FULL_WIDTH_IDEOGRAPHS: for #HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_SPACING_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_PROPORTIONAL_IDEOGRAPHS: for #HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_SPACING_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HALF_WIDTH_IDEOGRAPHS: for #HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_SPACING_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CANONICAL_COMPOSITION_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_UNICODE_DECOMPOSITION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CANONICAL_COMPOSITION_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_UNICODE_DECOMPOSITION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_COMPATIBILITY_COMPOSITION_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_UNICODE_DECOMPOSITION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_COMPATIBILITY_COMPOSITION_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_UNICODE_DECOMPOSITION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_TRANSCODING_COMPOSITION_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_UNICODE_DECOMPOSITION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_TRANSCODING_COMPOSITION_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_UNICODE_DECOMPOSITION_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_RUBY_KANA: Deprecated; use #HB_AAT_LAYOUT_FEATURE_SELECTOR_RUBY_KANA_OFF instead
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_RUBY_KANA: Deprecated; use #HB_AAT_LAYOUT_FEATURE_SELECTOR_RUBY_KANA_ON instead
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_RUBY_KANA_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_RUBY_KANA
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_RUBY_KANA_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_RUBY_KANA
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_CJK_SYMBOL_ALTERNATIVES: for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_SYMBOL_ALTERNATIVES_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_SYMBOL_ALT_ONE: for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_SYMBOL_ALTERNATIVES_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_SYMBOL_ALT_TWO: for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_SYMBOL_ALTERNATIVES_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_SYMBOL_ALT_THREE: for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_SYMBOL_ALTERNATIVES_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_SYMBOL_ALT_FOUR: for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_SYMBOL_ALTERNATIVES_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_SYMBOL_ALT_FIVE: for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_SYMBOL_ALTERNATIVES_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_IDEOGRAPHIC_ALTERNATIVES: for #HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_ALTERNATIVES_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_IDEOGRAPHIC_ALT_ONE: for #HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_ALTERNATIVES_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_IDEOGRAPHIC_ALT_TWO: for #HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_ALTERNATIVES_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_IDEOGRAPHIC_ALT_THREE: for #HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_ALTERNATIVES_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_IDEOGRAPHIC_ALT_FOUR: for #HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_ALTERNATIVES_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_IDEOGRAPHIC_ALT_FIVE: for #HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_ALTERNATIVES_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_VERTICAL_ROMAN_CENTERED: for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_VERTICAL_ROMAN_PLACEMENT_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_VERTICAL_ROMAN_HBASELINE: for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_VERTICAL_ROMAN_PLACEMENT_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_CJK_ITALIC_ROMAN: Deprecated; use #HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_ITALIC_ROMAN_OFF instead
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_ITALIC_ROMAN: Deprecated; use #HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_ITALIC_ROMAN_ON instead
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_ITALIC_ROMAN_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_ITALIC_CJK_ROMAN
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_ITALIC_ROMAN_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_ITALIC_CJK_ROMAN
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CASE_SENSITIVE_LAYOUT_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_CASE_SENSITIVE_LAYOUT
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CASE_SENSITIVE_LAYOUT_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_CASE_SENSITIVE_LAYOUT
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CASE_SENSITIVE_SPACING_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_CASE_SENSITIVE_LAYOUT
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CASE_SENSITIVE_SPACING_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_CASE_SENSITIVE_LAYOUT
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ALTERNATE_HORIZ_KANA_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_ALTERNATE_KANA
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ALTERNATE_HORIZ_KANA_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_ALTERNATE_KANA
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ALTERNATE_VERT_KANA_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_ALTERNATE_KANA
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_ALTERNATE_VERT_KANA_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_ALTERNATE_KANA
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_STYLISTIC_ALTERNATES: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_ONE_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_ONE_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TWO_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TWO_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_THREE_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_THREE_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FOUR_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FOUR_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FIVE_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FIVE_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SIX_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SIX_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SEVEN_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SEVEN_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_EIGHT_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_EIGHT_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_NINE_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_NINE_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TEN_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TEN_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_ELEVEN_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_ELEVEN_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TWELVE_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TWELVE_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_THIRTEEN_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_THIRTEEN_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FOURTEEN_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FOURTEEN_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FIFTEEN_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FIFTEEN_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SIXTEEN_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SIXTEEN_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SEVENTEEN_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SEVENTEEN_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_EIGHTEEN_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_EIGHTEEN_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_NINETEEN_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_NINETEEN_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TWENTY_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TWENTY_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CONTEXTUAL_ALTERNATES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_CONTEXTUAL_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CONTEXTUAL_ALTERNATES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_CONTEXTUAL_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SWASH_ALTERNATES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_CONTEXTUAL_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_SWASH_ALTERNATES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_CONTEXTUAL_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CONTEXTUAL_SWASH_ALTERNATES_ON: for #HB_AAT_LAYOUT_FEATURE_TYPE_CONTEXTUAL_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_CONTEXTUAL_SWASH_ALTERNATES_OFF: for #HB_AAT_LAYOUT_FEATURE_TYPE_CONTEXTUAL_ALTERNATIVES
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DEFAULT_LOWER_CASE: for #HB_AAT_LAYOUT_FEATURE_TYPE_LOWER_CASE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_LOWER_CASE_SMALL_CAPS: for #HB_AAT_LAYOUT_FEATURE_TYPE_LOWER_CASE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_LOWER_CASE_PETITE_CAPS: for #HB_AAT_LAYOUT_FEATURE_TYPE_LOWER_CASE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DEFAULT_UPPER_CASE: for #HB_AAT_LAYOUT_FEATURE_TYPE_UPPER_CASE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_UPPER_CASE_SMALL_CAPS: for #HB_AAT_LAYOUT_FEATURE_TYPE_UPPER_CASE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_UPPER_CASE_PETITE_CAPS: for #HB_AAT_LAYOUT_FEATURE_TYPE_UPPER_CASE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_HALF_WIDTH_CJK_ROMAN: for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_ROMAN_SPACING_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_PROPORTIONAL_CJK_ROMAN: for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_ROMAN_SPACING_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_DEFAULT_CJK_ROMAN: for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_ROMAN_SPACING_TYPE
 * @HB_AAT_LAYOUT_FEATURE_SELECTOR_FULL_WIDTH_CJK_ROMAN: for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_ROMAN_SPACING_TYPE
 *
 * The selectors defined for specifying AAT feature settings.
 *
 * Since: 2.2.0
 */
typedef enum
{
  HB_AAT_LAYOUT_FEATURE_SELECTOR_INVALID			= 0xFFFF,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_ALL_TYPOGRAPHIC */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ALL_TYPE_FEATURES_ON		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ALL_TYPE_FEATURES_OFF		= 1,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_REQUIRED_LIGATURES_ON		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_REQUIRED_LIGATURES_OFF		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_COMMON_LIGATURES_ON		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_COMMON_LIGATURES_OFF		= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_RARE_LIGATURES_ON		= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_RARE_LIGATURES_OFF		= 5,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_LOGOS_ON			= 6,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_LOGOS_OFF			= 7,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_REBUS_PICTURES_ON		= 8,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_REBUS_PICTURES_OFF		= 9,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DIPHTHONG_LIGATURES_ON		= 10,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DIPHTHONG_LIGATURES_OFF	= 11,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SQUARED_LIGATURES_ON		= 12,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SQUARED_LIGATURES_OFF		= 13,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ABBREV_SQUARED_LIGATURES_ON	= 14,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ABBREV_SQUARED_LIGATURES_OFF	= 15,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SYMBOL_LIGATURES_ON		= 16,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SYMBOL_LIGATURES_OFF		= 17,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CONTEXTUAL_LIGATURES_ON	= 18,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CONTEXTUAL_LIGATURES_OFF	= 19,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HISTORICAL_LIGATURES_ON	= 20,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HISTORICAL_LIGATURES_OFF	= 21,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_LIGATURES */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_UNCONNECTED			= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_PARTIALLY_CONNECTED		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CURSIVE			= 2,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_LETTER_CASE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_UPPER_AND_LOWER_CASE		= 0, /* deprecated */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ALL_CAPS			= 1, /* deprecated */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ALL_LOWER_CASE			= 2, /* deprecated */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SMALL_CAPS			= 3, /* deprecated */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_INITIAL_CAPS			= 4, /* deprecated */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_INITIAL_CAPS_AND_SMALL_CAPS	= 5, /* deprecated */

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_SUBSTITUTION */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SUBSTITUTE_VERTICAL_FORMS_ON	= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SUBSTITUTE_VERTICAL_FORMS_OFF	= 1,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_LINGUISTIC_REARRANGEMENT */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_LINGUISTIC_REARRANGEMENT_ON	= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_LINGUISTIC_REARRANGEMENT_OFF	= 1,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_SPACING */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_MONOSPACED_NUMBERS		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_PROPORTIONAL_NUMBERS		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_THIRD_WIDTH_NUMBERS		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_QUARTER_WIDTH_NUMBERS		= 3,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_SMART_SWASH_TYPE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_WORD_INITIAL_SWASHES_ON	= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_WORD_INITIAL_SWASHES_OFF	= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_WORD_FINAL_SWASHES_ON		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_WORD_FINAL_SWASHES_OFF		= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_LINE_INITIAL_SWASHES_ON	= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_LINE_INITIAL_SWASHES_OFF	= 5,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_LINE_FINAL_SWASHES_ON		= 6,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_LINE_FINAL_SWASHES_OFF		= 7,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NON_FINAL_SWASHES_ON		= 8,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NON_FINAL_SWASHES_OFF		= 9,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_DIACRITICS_TYPE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SHOW_DIACRITICS		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HIDE_DIACRITICS		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DECOMPOSE_DIACRITICS		= 2,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_VERTICAL_POSITION */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NORMAL_POSITION		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SUPERIORS			= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_INFERIORS			= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ORDINALS			= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SCIENTIFIC_INFERIORS		= 4,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_FRACTIONS */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_FRACTIONS			= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_VERTICAL_FRACTIONS		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DIAGONAL_FRACTIONS		= 2,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_OVERLAPPING_CHARACTERS_TYPE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_PREVENT_OVERLAP_ON		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_PREVENT_OVERLAP_OFF		= 1,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HYPHENS_TO_EM_DASH_ON		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HYPHENS_TO_EM_DASH_OFF		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HYPHEN_TO_EN_DASH_ON		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HYPHEN_TO_EN_DASH_OFF		= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SLASHED_ZERO_ON		= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SLASHED_ZERO_OFF		= 5,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_FORM_INTERROBANG_ON		= 6,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_FORM_INTERROBANG_OFF		= 7,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SMART_QUOTES_ON		= 8,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SMART_QUOTES_OFF		= 9,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_PERIODS_TO_ELLIPSIS_ON		= 10,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_PERIODS_TO_ELLIPSIS_OFF	= 11,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_MATHEMATICAL_EXTRAS */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HYPHEN_TO_MINUS_ON		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HYPHEN_TO_MINUS_OFF		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ASTERISK_TO_MULTIPLY_ON	= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ASTERISK_TO_MULTIPLY_OFF	= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SLASH_TO_DIVIDE_ON		= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SLASH_TO_DIVIDE_OFF		= 5,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_INEQUALITY_LIGATURES_ON	= 6,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_INEQUALITY_LIGATURES_OFF	= 7,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_EXPONENTS_ON			= 8,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_EXPONENTS_OFF			= 9,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_MATHEMATICAL_GREEK_ON		= 10,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_MATHEMATICAL_GREEK_OFF		= 11,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_ORNAMENT_SETS_TYPE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_ORNAMENTS			= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DINGBATS			= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_PI_CHARACTERS			= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_FLEURONS			= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DECORATIVE_BORDERS		= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_INTERNATIONAL_SYMBOLS		= 5,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_MATH_SYMBOLS			= 6,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_ALTERNATIVES */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_ALTERNATES			= 0,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_DESIGN_COMPLEXITY_TYPE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DESIGN_LEVEL1			= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DESIGN_LEVEL2			= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DESIGN_LEVEL3			= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DESIGN_LEVEL4			= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DESIGN_LEVEL5			= 4,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLE_OPTIONS */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_STYLE_OPTIONS		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DISPLAY_TEXT			= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ENGRAVED_TEXT			= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ILLUMINATED_CAPS		= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_TITLING_CAPS			= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_TALL_CAPS			= 5,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_SHAPE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_TRADITIONAL_CHARACTERS		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SIMPLIFIED_CHARACTERS		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_JIS1978_CHARACTERS		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_JIS1983_CHARACTERS		= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_JIS1990_CHARACTERS		= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_TRADITIONAL_ALT_ONE		= 5,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_TRADITIONAL_ALT_TWO		= 6,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_TRADITIONAL_ALT_THREE		= 7,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_TRADITIONAL_ALT_FOUR		= 8,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_TRADITIONAL_ALT_FIVE		= 9,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_EXPERT_CHARACTERS		= 10,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_JIS2004_CHARACTERS		= 11,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HOJO_CHARACTERS		= 12,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NLCCHARACTERS			= 13,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_TRADITIONAL_NAMES_CHARACTERS	= 14,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_NUMBER_CASE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_LOWER_CASE_NUMBERS		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_UPPER_CASE_NUMBERS		= 1,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_TEXT_SPACING */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_PROPORTIONAL_TEXT		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_MONOSPACED_TEXT		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HALF_WIDTH_TEXT		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_THIRD_WIDTH_TEXT		= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_QUARTER_WIDTH_TEXT		= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ALT_PROPORTIONAL_TEXT		= 5,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ALT_HALF_WIDTH_TEXT		= 6,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_TRANSLITERATION */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_TRANSLITERATION		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HANJA_TO_HANGUL		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HIRAGANA_TO_KATAKANA		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_KATAKANA_TO_HIRAGANA		= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_KANA_TO_ROMANIZATION		= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ROMANIZATION_TO_HIRAGANA	= 5,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ROMANIZATION_TO_KATAKANA	= 6,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HANJA_TO_HANGUL_ALT_ONE	= 7,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HANJA_TO_HANGUL_ALT_TWO	= 8,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HANJA_TO_HANGUL_ALT_THREE	= 9,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_ANNOTATION_TYPE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_ANNOTATION			= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_BOX_ANNOTATION			= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ROUNDED_BOX_ANNOTATION		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CIRCLE_ANNOTATION		= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_INVERTED_CIRCLE_ANNOTATION	= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_PARENTHESIS_ANNOTATION		= 5,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_PERIOD_ANNOTATION		= 6,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ROMAN_NUMERAL_ANNOTATION	= 7,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DIAMOND_ANNOTATION		= 8,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_INVERTED_BOX_ANNOTATION	= 9,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_INVERTED_ROUNDED_BOX_ANNOTATION= 10,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_KANA_SPACING_TYPE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_FULL_WIDTH_KANA		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_PROPORTIONAL_KANA		= 1,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_SPACING_TYPE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_FULL_WIDTH_IDEOGRAPHS		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_PROPORTIONAL_IDEOGRAPHS	= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HALF_WIDTH_IDEOGRAPHS		= 2,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_UNICODE_DECOMPOSITION_TYPE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CANONICAL_COMPOSITION_ON	= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CANONICAL_COMPOSITION_OFF	= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_COMPATIBILITY_COMPOSITION_ON	= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_COMPATIBILITY_COMPOSITION_OFF	= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_TRANSCODING_COMPOSITION_ON	= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_TRANSCODING_COMPOSITION_OFF	= 5,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_RUBY_KANA */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_RUBY_KANA			= 0, /* deprecated - use HB_AAT_LAYOUT_FEATURE_SELECTOR_RUBY_KANA_OFF instead */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_RUBY_KANA			= 1, /* deprecated - use HB_AAT_LAYOUT_FEATURE_SELECTOR_RUBY_KANA_ON instead */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_RUBY_KANA_ON			= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_RUBY_KANA_OFF			= 3,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_SYMBOL_ALTERNATIVES_TYPE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_CJK_SYMBOL_ALTERNATIVES	= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_SYMBOL_ALT_ONE		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_SYMBOL_ALT_TWO		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_SYMBOL_ALT_THREE		= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_SYMBOL_ALT_FOUR		= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_SYMBOL_ALT_FIVE		= 5,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_IDEOGRAPHIC_ALTERNATIVES_TYPE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_IDEOGRAPHIC_ALTERNATIVES	= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_IDEOGRAPHIC_ALT_ONE		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_IDEOGRAPHIC_ALT_TWO		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_IDEOGRAPHIC_ALT_THREE		= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_IDEOGRAPHIC_ALT_FOUR		= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_IDEOGRAPHIC_ALT_FIVE		= 5,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_VERTICAL_ROMAN_PLACEMENT_TYPE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_VERTICAL_ROMAN_CENTERED	= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_VERTICAL_ROMAN_HBASELINE	= 1,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_ITALIC_CJK_ROMAN */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_CJK_ITALIC_ROMAN		= 0,    /* deprecated - use HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_ITALIC_ROMAN_OFF instead */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_ITALIC_ROMAN		= 1,    /* deprecated - use HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_ITALIC_ROMAN_ON instead */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_ITALIC_ROMAN_ON		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CJK_ITALIC_ROMAN_OFF		= 3,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_CASE_SENSITIVE_LAYOUT */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CASE_SENSITIVE_LAYOUT_ON	= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CASE_SENSITIVE_LAYOUT_OFF	= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CASE_SENSITIVE_SPACING_ON	= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CASE_SENSITIVE_SPACING_OFF	= 3,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_ALTERNATE_KANA */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ALTERNATE_HORIZ_KANA_ON	= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ALTERNATE_HORIZ_KANA_OFF	= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ALTERNATE_VERT_KANA_ON		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_ALTERNATE_VERT_KANA_OFF	= 3,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_STYLISTIC_ALTERNATIVES */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_NO_STYLISTIC_ALTERNATES	= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_ONE_ON		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_ONE_OFF		= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TWO_ON		= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TWO_OFF		= 5,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_THREE_ON		= 6,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_THREE_OFF	= 7,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FOUR_ON		= 8,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FOUR_OFF		= 9,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FIVE_ON		= 10,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FIVE_OFF		= 11,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SIX_ON		= 12,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SIX_OFF		= 13,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SEVEN_ON		= 14,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SEVEN_OFF	= 15,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_EIGHT_ON		= 16,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_EIGHT_OFF	= 17,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_NINE_ON		= 18,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_NINE_OFF		= 19,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TEN_ON		= 20,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TEN_OFF		= 21,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_ELEVEN_ON	= 22,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_ELEVEN_OFF	= 23,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TWELVE_ON	= 24,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TWELVE_OFF	= 25,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_THIRTEEN_ON	= 26,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_THIRTEEN_OFF	= 27,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FOURTEEN_ON	= 28,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FOURTEEN_OFF	= 29,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FIFTEEN_ON	= 30,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_FIFTEEN_OFF	= 31,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SIXTEEN_ON	= 32,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SIXTEEN_OFF	= 33,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SEVENTEEN_ON	= 34,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_SEVENTEEN_OFF	= 35,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_EIGHTEEN_ON	= 36,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_EIGHTEEN_OFF	= 37,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_NINETEEN_ON	= 38,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_NINETEEN_OFF	= 39,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TWENTY_ON	= 40,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_STYLISTIC_ALT_TWENTY_OFF	= 41,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_CONTEXTUAL_ALTERNATIVES */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CONTEXTUAL_ALTERNATES_ON	= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CONTEXTUAL_ALTERNATES_OFF	= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SWASH_ALTERNATES_ON		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_SWASH_ALTERNATES_OFF		= 3,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CONTEXTUAL_SWASH_ALTERNATES_ON	= 4,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_CONTEXTUAL_SWASH_ALTERNATES_OFF= 5,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_LOWER_CASE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DEFAULT_LOWER_CASE		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_LOWER_CASE_SMALL_CAPS		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_LOWER_CASE_PETITE_CAPS		= 2,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_UPPER_CASE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DEFAULT_UPPER_CASE		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_UPPER_CASE_SMALL_CAPS		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_UPPER_CASE_PETITE_CAPS		= 2,

  /* Selectors for #HB_AAT_LAYOUT_FEATURE_TYPE_CJK_ROMAN_SPACING_TYPE */
  HB_AAT_LAYOUT_FEATURE_SELECTOR_HALF_WIDTH_CJK_ROMAN		= 0,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_PROPORTIONAL_CJK_ROMAN		= 1,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_DEFAULT_CJK_ROMAN		= 2,
  HB_AAT_LAYOUT_FEATURE_SELECTOR_FULL_WIDTH_CJK_ROMAN		= 3,

  /*< private >*/
  _HB_AAT_LAYOUT_FEATURE_SELECTOR_MAX_VALUE = HB_TAG_MAX_SIGNED /*< skip >*/
} hb_aat_layout_feature_selector_t;

HB_EXTERN unsigned int
hb_aat_layout_get_feature_types (hb_face_t                    *face,
				 unsigned int                  start_offset,
				 unsigned int                 *feature_count, /* IN/OUT.  May be NULL. */
				 hb_aat_layout_feature_type_t *features       /* OUT.     May be NULL. */);

HB_EXTERN hb_ot_name_id_t
hb_aat_layout_feature_type_get_name_id (hb_face_t                    *face,
					hb_aat_layout_feature_type_t  feature_type);

typedef struct hb_aat_layout_feature_selector_info_t
{
  hb_ot_name_id_t			name_id;
  hb_aat_layout_feature_selector_t	enable;
  hb_aat_layout_feature_selector_t	disable;
  /*< private >*/
  unsigned int				reserved;
} hb_aat_layout_feature_selector_info_t;

/**
 * HB_AAT_LAYOUT_NO_SELECTOR_INDEX
 *
 * Used when getting or setting AAT feature selectors. Indicates that
 * there is no selector index corresponding to the selector of interest.
 *
 */
#define HB_AAT_LAYOUT_NO_SELECTOR_INDEX		0xFFFFu

HB_EXTERN unsigned int
hb_aat_layout_feature_type_get_selector_infos (hb_face_t                             *face,
					       hb_aat_layout_feature_type_t           feature_type,
					       unsigned int                           start_offset,
					       unsigned int                          *selector_count, /* IN/OUT.  May be NULL. */
					       hb_aat_layout_feature_selector_info_t *selectors,      /* OUT.     May be NULL. */
					       unsigned int                          *default_index   /* OUT.     May be NULL. */);


/*
 * morx/mort
 */

HB_EXTERN hb_bool_t
hb_aat_layout_has_substitution (hb_face_t *face);


/*
 * kerx
 */

HB_EXTERN hb_bool_t
hb_aat_layout_has_positioning (hb_face_t *face);


/*
 * trak
 */

HB_EXTERN hb_bool_t
hb_aat_layout_has_tracking (hb_face_t *face);


HB_END_DECLS

#endif /* HB_AAT_LAYOUT_H */