src/hb-ot-os2-table.hh - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2011,2012  Google, Inc.
  * 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.
  *
  * Google Author(s): Behdad Esfahbod
  */

 #ifndef HB_OT_OS2_TABLE_HH
 #define HB_OT_OS2_TABLE_HH

 #include "hb-open-type.hh"
 #include "hb-ot-os2-unicode-ranges.hh"
 #include "hb-ot-var-mvar-table.hh"

 #include "hb-set.hh"

 /*
  * OS/2 and Windows Metrics
  * https://docs.microsoft.com/en-us/typography/opentype/spec/os2
  */
 #define HB_OT_TAG_OS2 HB_TAG('O','S','/','2')


 namespace OT {

 struct OS2V1Tail
 {
   bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
     return_trace (c->check_struct (this));
   }

   public:
   HBUINT32	ulCodePageRange1;
   HBUINT32	ulCodePageRange2;
   public:
   DEFINE_SIZE_STATIC (8);
 };

 struct OS2V2Tail
 {
   bool has_data () const { return sxHeight || sCapHeight; }

   const OS2V2Tail * operator -> () const { return this; }
   OS2V2Tail * operator -> () { return this; }

   bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
     return_trace (c->check_struct (this));
   }

   public:
   HBINT16	sxHeight;
   HBINT16	sCapHeight;
   HBUINT16	usDefaultChar;
   HBUINT16	usBreakChar;
   HBUINT16	usMaxContext;
   public:
   DEFINE_SIZE_STATIC (10);
 };

 struct OS2V5Tail
 {
   inline bool get_optical_size (unsigned int *lower, unsigned int *upper) const
   {
     unsigned int lower_optical_size = usLowerOpticalPointSize;
     unsigned int upper_optical_size = usUpperOpticalPointSize;

     /* Per https://docs.microsoft.com/en-us/typography/opentype/spec/os2#lps */
     if (lower_optical_size < upper_optical_size &&
 	lower_optical_size >= 1 && lower_optical_size <= 0xFFFE &&
 	upper_optical_size >= 2 && upper_optical_size <= 0xFFFF)
     {
       *lower = lower_optical_size;
       *upper = upper_optical_size;
       return true;
     }
     return false;
   }

   bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
     return_trace (c->check_struct (this));
   }

   public:
   HBUINT16	usLowerOpticalPointSize;
   HBUINT16	usUpperOpticalPointSize;
   public:
   DEFINE_SIZE_STATIC (4);
 };

 struct OS2
 {
   static constexpr hb_tag_t tableTag = HB_OT_TAG_OS2;

   bool has_data () const { return usWeightClass || usWidthClass || usFirstCharIndex || usLastCharIndex; }

   const OS2V1Tail &v1 () const { return version >= 1 ? v1X : Null (OS2V1Tail); }
   const OS2V2Tail &v2 () const { return version >= 2 ? v2X : Null (OS2V2Tail); }
   const OS2V5Tail &v5 () const { return version >= 5 ? v5X : Null (OS2V5Tail); }

   enum selection_flag_t {
     ITALIC		= 1u<<0,
     UNDERSCORE		= 1u<<1,
     NEGATIVE		= 1u<<2,
     OUTLINED		= 1u<<3,
     STRIKEOUT		= 1u<<4,
     BOLD		= 1u<<5,
     REGULAR		= 1u<<6,
     USE_TYPO_METRICS	= 1u<<7,
     WWS			= 1u<<8,
     OBLIQUE		= 1u<<9
   };

   bool        is_italic () const { return fsSelection & ITALIC; }
   bool       is_oblique () const { return fsSelection & OBLIQUE; }
   bool use_typo_metrics () const { return fsSelection & USE_TYPO_METRICS; }

   enum width_class_t {
     FWIDTH_ULTRA_CONDENSED	= 1, /* 50% */
     FWIDTH_EXTRA_CONDENSED	= 2, /* 62.5% */
     FWIDTH_CONDENSED		= 3, /* 75% */
     FWIDTH_SEMI_CONDENSED	= 4, /* 87.5% */
     FWIDTH_NORMAL		= 5, /* 100% */
     FWIDTH_SEMI_EXPANDED	= 6, /* 112.5% */
     FWIDTH_EXPANDED		= 7, /* 125% */
     FWIDTH_EXTRA_EXPANDED	= 8, /* 150% */
     FWIDTH_ULTRA_EXPANDED	= 9  /* 200% */
   };

   float get_width () const
   {
     switch (usWidthClass) {
     case FWIDTH_ULTRA_CONDENSED:return 50.f;
     case FWIDTH_EXTRA_CONDENSED:return 62.5f;
     case FWIDTH_CONDENSED:	return 75.f;
     case FWIDTH_SEMI_CONDENSED:	return 87.5f;
     default:
     case FWIDTH_NORMAL:		return 100.f;
     case FWIDTH_SEMI_EXPANDED:	return 112.5f;
     case FWIDTH_EXPANDED:	return 125.f;
     case FWIDTH_EXTRA_EXPANDED:	return 150.f;
     case FWIDTH_ULTRA_EXPANDED:	return 200.f;
     }
   }

   float map_wdth_to_widthclass(float width) const
   {
     if (width < 50) return 1.0f;
     if (width > 200) return 9.0f;

     float ratio = (width - 50) / 12.5f;
     int a = (int) floorf (ratio);
     int b = (int) ceilf (ratio);

     /* follow this maping:
      * https://docs.microsoft.com/en-us/typography/opentype/spec/os2#uswidthclass
      */
     if (b <= 6) // 50-125
     {
       if (a == b) return a + 1.0f;
     }
     else if (b == 7) // no mapping for 137.5
     {
       a = 6;
       b = 8;
     }
     else if (b == 8)
     {
       if (a == b) return 8.0f; // 150
       a = 6;
     }
     else
     {
       if (a == b && a == 12) return 9.0f; //200
       b = 12;
       a = 8;
     }

     float va = 50 + a * 12.5f;
     float vb = 50 + b * 12.5f;

     float ret =  a + (width - va) / (vb - va);
     if (a <= 6) ret += 1.0f;
     return ret;
   }

   bool subset (hb_subset_context_t *c) const
   {
     TRACE_SUBSET (this);
     OS2 *os2_prime = c->serializer->embed (this);
     if (unlikely (!os2_prime)) return_trace (false);

 #ifndef HB_NO_VAR
     if (c->plan->normalized_coords)
     {
       auto &MVAR = *c->plan->source->table.MVAR;
       auto *table = os2_prime;

       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER,         sTypoAscender);
       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER,        sTypoDescender);
       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP,         sTypoLineGap);
       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_ASCENT,  usWinAscent);
       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_DESCENT, usWinDescent);
       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_SIZE,         ySubscriptXSize);
       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_SIZE,         ySubscriptYSize);
       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_OFFSET,       ySubscriptXOffset);
       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_OFFSET,       ySubscriptYOffset);
       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_SIZE,       ySuperscriptXSize);
       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_SIZE,       ySuperscriptYSize);
       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_OFFSET,     ySuperscriptXOffset);
       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_OFFSET,     ySuperscriptYOffset);
       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_STRIKEOUT_SIZE,              yStrikeoutSize);
       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_STRIKEOUT_OFFSET,            yStrikeoutPosition);

       if (os2_prime->version >= 2)
       {
         auto *table = & const_cast<OS2V2Tail &> (os2_prime->v2 ());
         HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_X_HEIGHT,                   sxHeight);
         HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_CAP_HEIGHT,                 sCapHeight);
       }
     }
 #endif

     Triple *axis_range;
     if (c->plan->user_axes_location.has (HB_TAG ('w','g','h','t'), &axis_range))
     {
       unsigned weight_class = static_cast<unsigned> (roundf (hb_clamp (axis_range->middle, 1.0f, 1000.0f)));
       if (os2_prime->usWeightClass != weight_class)
         os2_prime->usWeightClass = weight_class;
     }

     if (c->plan->user_axes_location.has (HB_TAG ('w','d','t','h'), &axis_range))
     {
       unsigned width_class = static_cast<unsigned> (roundf (map_wdth_to_widthclass (axis_range->middle)));
       if (os2_prime->usWidthClass != width_class)
         os2_prime->usWidthClass = width_class;
     }

     if (c->plan->flags & HB_SUBSET_FLAGS_NO_PRUNE_UNICODE_RANGES)
       return_trace (true);

     os2_prime->usFirstCharIndex = hb_min (0xFFFFu, c->plan->unicodes.get_min ());
     os2_prime->usLastCharIndex  = hb_min (0xFFFFu, c->plan->unicodes.get_max ());

     _update_unicode_ranges (&c->plan->unicodes, os2_prime->ulUnicodeRange);

     return_trace (true);
   }

   void _update_unicode_ranges (const hb_set_t *codepoints,
 			       HBUINT32 ulUnicodeRange[4]) const
   {
     HBUINT32 newBits[4];
     for (unsigned int i = 0; i < 4; i++)
       newBits[i] = 0;

     /* This block doesn't show up in profiles. If it ever did,
      * we can rewrite it to iterate over OS/2 ranges and use
      * set iteration to check if the range matches. */
     for (auto cp : *codepoints)
     {
       unsigned int bit = _hb_ot_os2_get_unicode_range_bit (cp);
       if (bit < 128)
       {
 	unsigned int block = bit / 32;
 	unsigned int bit_in_block = bit % 32;
 	unsigned int mask = 1 << bit_in_block;
 	newBits[block] = newBits[block] | mask;
       }
       if (cp >= 0x10000 && cp <= 0x110000)
       {
 	/* the spec says that bit 57 ("Non Plane 0") implies that there's
 	   at least one codepoint beyond the BMP; so I also include all
 	   the non-BMP codepoints here */
 	newBits[1] = newBits[1] | (1 << 25);
       }
     }

     for (unsigned int i = 0; i < 4; i++)
       ulUnicodeRange[i] = ulUnicodeRange[i] & newBits[i]; // set bits only if set in the original
   }

   /* https://github.com/Microsoft/Font-Validator/blob/520aaae/OTFontFileVal/val_OS2.cs#L644-L681
    * https://docs.microsoft.com/en-us/typography/legacy/legacy_arabic_fonts */
   enum font_page_t
   {
     FONT_PAGE_NONE		= 0,
     FONT_PAGE_HEBREW		= 0xB100, /* Hebrew Windows 3.1 font page */
     FONT_PAGE_SIMP_ARABIC	= 0xB200, /* Simplified Arabic Windows 3.1 font page */
     FONT_PAGE_TRAD_ARABIC	= 0xB300, /* Traditional Arabic Windows 3.1 font page */
     FONT_PAGE_OEM_ARABIC	= 0xB400, /* OEM Arabic Windows 3.1 font page */
     FONT_PAGE_SIMP_FARSI	= 0xBA00, /* Simplified Farsi Windows 3.1 font page */
     FONT_PAGE_TRAD_FARSI	= 0xBB00, /* Traditional Farsi Windows 3.1 font page */
     FONT_PAGE_THAI		= 0xDE00  /* Thai Windows 3.1 font page */
   };
   font_page_t get_font_page () const
   { return (font_page_t) (version == 0 ? fsSelection & 0xFF00 : 0); }

   unsigned get_size () const
   {
     unsigned result = min_size;
     if (version >= 1) result += v1X.get_size ();
     if (version >= 2) result += v2X.get_size ();
     if (version >= 5) result += v5X.get_size ();
     return result;
   }

   bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
     if (unlikely (!c->check_struct (this))) return_trace (false);
     if (unlikely (version >= 1 && !v1X.sanitize (c))) return_trace (false);
     if (unlikely (version >= 2 && !v2X.sanitize (c))) return_trace (false);
     if (unlikely (version >= 5 && !v5X.sanitize (c))) return_trace (false);
     return_trace (true);
   }

   public:
   HBUINT16	version;
   HBINT16	xAvgCharWidth;
   HBUINT16	usWeightClass;
   HBUINT16	usWidthClass;
   HBUINT16	fsType;
   HBINT16	ySubscriptXSize;
   HBINT16	ySubscriptYSize;
   HBINT16	ySubscriptXOffset;
   HBINT16	ySubscriptYOffset;
   HBINT16	ySuperscriptXSize;
   HBINT16	ySuperscriptYSize;
   HBINT16	ySuperscriptXOffset;
   HBINT16	ySuperscriptYOffset;
   HBINT16	yStrikeoutSize;
   HBINT16	yStrikeoutPosition;
   HBINT16	sFamilyClass;
   HBUINT8	panose[10];
   HBUINT32	ulUnicodeRange[4];
   Tag		achVendID;
   HBUINT16	fsSelection;
   HBUINT16	usFirstCharIndex;
   HBUINT16	usLastCharIndex;
   HBINT16	sTypoAscender;
   HBINT16	sTypoDescender;
   HBINT16	sTypoLineGap;
   HBUINT16	usWinAscent;
   HBUINT16	usWinDescent;
   OS2V1Tail	v1X;
   OS2V2Tail	v2X;
   OS2V5Tail	v5X;
   public:
   DEFINE_SIZE_MIN (78);
 };

 } /* namespace OT */


 #endif /* HB_OT_OS2_TABLE_HH */
	/*
	* Copyright © 2011,2012 Google, Inc.
	* 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.
	*
	* Google Author(s): Behdad Esfahbod
	*/

	#ifndef HB_OT_OS2_TABLE_HH
	#define HB_OT_OS2_TABLE_HH

	#include "hb-open-type.hh"
	#include "hb-ot-os2-unicode-ranges.hh"
	#include "hb-ot-var-mvar-table.hh"

	#include "hb-set.hh"

	/*
	* OS/2 and Windows Metrics
	* https://docs.microsoft.com/en-us/typography/opentype/spec/os2
	*/
	#define HB_OT_TAG_OS2 HB_TAG('O','S','/','2')


	namespace OT {

	struct OS2V1Tail
	{
	bool sanitize (hb_sanitize_context_t *c) const
	{
	TRACE_SANITIZE (this);
	return_trace (c->check_struct (this));
	}

	public:
	HBUINT32 ulCodePageRange1;
	HBUINT32 ulCodePageRange2;
	public:
	DEFINE_SIZE_STATIC (8);
	};

	struct OS2V2Tail
	{
	bool has_data () const { return sxHeight \|\| sCapHeight; }

	const OS2V2Tail * operator -> () const { return this; }
	OS2V2Tail * operator -> () { return this; }

	bool sanitize (hb_sanitize_context_t *c) const
	{
	TRACE_SANITIZE (this);
	return_trace (c->check_struct (this));
	}

	public:
	HBINT16 sxHeight;
	HBINT16 sCapHeight;
	HBUINT16 usDefaultChar;
	HBUINT16 usBreakChar;
	HBUINT16 usMaxContext;
	public:
	DEFINE_SIZE_STATIC (10);
	};

	struct OS2V5Tail
	{
	inline bool get_optical_size (unsigned int lower, unsigned int upper) const
	{
	unsigned int lower_optical_size = usLowerOpticalPointSize;
	unsigned int upper_optical_size = usUpperOpticalPointSize;

	/* Per https://docs.microsoft.com/en-us/typography/opentype/spec/os2#lps */
	if (lower_optical_size < upper_optical_size &&
	lower_optical_size >= 1 && lower_optical_size <= 0xFFFE &&
	upper_optical_size >= 2 && upper_optical_size <= 0xFFFF)
	{
	*lower = lower_optical_size;
	*upper = upper_optical_size;
	return true;
	}
	return false;
	}

	bool sanitize (hb_sanitize_context_t *c) const
	{
	TRACE_SANITIZE (this);
	return_trace (c->check_struct (this));
	}

	public:
	HBUINT16 usLowerOpticalPointSize;
	HBUINT16 usUpperOpticalPointSize;
	public:
	DEFINE_SIZE_STATIC (4);
	};

	struct OS2
	{
	static constexpr hb_tag_t tableTag = HB_OT_TAG_OS2;

	bool has_data () const { return usWeightClass \|\| usWidthClass \|\| usFirstCharIndex \|\| usLastCharIndex; }

	const OS2V1Tail &v1 () const { return version >= 1 ? v1X : Null (OS2V1Tail); }
	const OS2V2Tail &v2 () const { return version >= 2 ? v2X : Null (OS2V2Tail); }
	const OS2V5Tail &v5 () const { return version >= 5 ? v5X : Null (OS2V5Tail); }

	enum selection_flag_t {
	ITALIC = 1u<<0,
	UNDERSCORE = 1u<<1,
	NEGATIVE = 1u<<2,
	OUTLINED = 1u<<3,
	STRIKEOUT = 1u<<4,
	BOLD = 1u<<5,
	REGULAR = 1u<<6,
	USE_TYPO_METRICS = 1u<<7,
	WWS = 1u<<8,
	OBLIQUE = 1u<<9
	};

	bool is_italic () const { return fsSelection & ITALIC; }
	bool is_oblique () const { return fsSelection & OBLIQUE; }
	bool use_typo_metrics () const { return fsSelection & USE_TYPO_METRICS; }

	enum width_class_t {
	FWIDTH_ULTRA_CONDENSED = 1, /* 50% */
	FWIDTH_EXTRA_CONDENSED = 2, /* 62.5% */
	FWIDTH_CONDENSED = 3, /* 75% */
	FWIDTH_SEMI_CONDENSED = 4, /* 87.5% */
	FWIDTH_NORMAL = 5, /* 100% */
	FWIDTH_SEMI_EXPANDED = 6, /* 112.5% */
	FWIDTH_EXPANDED = 7, /* 125% */
	FWIDTH_EXTRA_EXPANDED = 8, /* 150% */
	FWIDTH_ULTRA_EXPANDED = 9 /* 200% */
	};

	float get_width () const
	{
	switch (usWidthClass) {
	case FWIDTH_ULTRA_CONDENSED:return 50.f;
	case FWIDTH_EXTRA_CONDENSED:return 62.5f;
	case FWIDTH_CONDENSED: return 75.f;
	case FWIDTH_SEMI_CONDENSED: return 87.5f;
	default:
	case FWIDTH_NORMAL: return 100.f;
	case FWIDTH_SEMI_EXPANDED: return 112.5f;
	case FWIDTH_EXPANDED: return 125.f;
	case FWIDTH_EXTRA_EXPANDED: return 150.f;
	case FWIDTH_ULTRA_EXPANDED: return 200.f;
	}
	}

	float map_wdth_to_widthclass(float width) const
	{
	if (width < 50) return 1.0f;
	if (width > 200) return 9.0f;

	float ratio = (width - 50) / 12.5f;
	int a = (int) floorf (ratio);
	int b = (int) ceilf (ratio);

	/* follow this maping:
	* https://docs.microsoft.com/en-us/typography/opentype/spec/os2#uswidthclass
	*/
	if (b <= 6) // 50-125
	{
	if (a == b) return a + 1.0f;
	}
	else if (b == 7) // no mapping for 137.5
	{
	a = 6;
	b = 8;
	}
	else if (b == 8)
	{
	if (a == b) return 8.0f; // 150
	a = 6;
	}
	else
	{
	if (a == b && a == 12) return 9.0f; //200
	b = 12;
	a = 8;
	}

	float va = 50 + a * 12.5f;
	float vb = 50 + b * 12.5f;

	float ret = a + (width - va) / (vb - va);
	if (a <= 6) ret += 1.0f;
	return ret;
	}

	bool subset (hb_subset_context_t *c) const
	{
	TRACE_SUBSET (this);
	OS2 *os2_prime = c->serializer->embed (this);
	if (unlikely (!os2_prime)) return_trace (false);

	#ifndef HB_NO_VAR
	if (c->plan->normalized_coords)
	{
	auto &MVAR = *c->plan->source->table.MVAR;
	auto *table = os2_prime;

	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_HORIZONTAL_ASCENDER, sTypoAscender);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_HORIZONTAL_DESCENDER, sTypoDescender);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_HORIZONTAL_LINE_GAP, sTypoLineGap);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_ASCENT, usWinAscent);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_HORIZONTAL_CLIPPING_DESCENT, usWinDescent);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_SIZE, ySubscriptXSize);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_SIZE, ySubscriptYSize);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUBSCRIPT_EM_X_OFFSET, ySubscriptXOffset);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUBSCRIPT_EM_Y_OFFSET, ySubscriptYOffset);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_SIZE, ySuperscriptXSize);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_SIZE, ySuperscriptYSize);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUPERSCRIPT_EM_X_OFFSET, ySuperscriptXOffset);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_SUPERSCRIPT_EM_Y_OFFSET, ySuperscriptYOffset);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_STRIKEOUT_SIZE, yStrikeoutSize);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_STRIKEOUT_OFFSET, yStrikeoutPosition);

	if (os2_prime->version >= 2)
	{
	auto *table = & const_cast<OS2V2Tail &> (os2_prime->v2 ());
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_X_HEIGHT, sxHeight);
	HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_CAP_HEIGHT, sCapHeight);
	}
	}
	#endif

	Triple *axis_range;
	if (c->plan->user_axes_location.has (HB_TAG ('w','g','h','t'), &axis_range))
	{
	unsigned weight_class = static_cast<unsigned> (roundf (hb_clamp (axis_range->middle, 1.0f, 1000.0f)));
	if (os2_prime->usWeightClass != weight_class)
	os2_prime->usWeightClass = weight_class;
	}

	if (c->plan->user_axes_location.has (HB_TAG ('w','d','t','h'), &axis_range))
	{
	unsigned width_class = static_cast<unsigned> (roundf (map_wdth_to_widthclass (axis_range->middle)));
	if (os2_prime->usWidthClass != width_class)
	os2_prime->usWidthClass = width_class;
	}

	if (c->plan->flags & HB_SUBSET_FLAGS_NO_PRUNE_UNICODE_RANGES)
	return_trace (true);

	os2_prime->usFirstCharIndex = hb_min (0xFFFFu, c->plan->unicodes.get_min ());
	os2_prime->usLastCharIndex = hb_min (0xFFFFu, c->plan->unicodes.get_max ());

	_update_unicode_ranges (&c->plan->unicodes, os2_prime->ulUnicodeRange);

	return_trace (true);
	}

	void _update_unicode_ranges (const hb_set_t *codepoints,
	HBUINT32 ulUnicodeRange[4]) const
	{
	HBUINT32 newBits[4];
	for (unsigned int i = 0; i < 4; i++)
	newBits[i] = 0;

	/* This block doesn't show up in profiles. If it ever did,
	* we can rewrite it to iterate over OS/2 ranges and use
	* set iteration to check if the range matches. */
	for (auto cp : *codepoints)
	{
	unsigned int bit = _hb_ot_os2_get_unicode_range_bit (cp);
	if (bit < 128)
	{
	unsigned int block = bit / 32;
	unsigned int bit_in_block = bit % 32;
	unsigned int mask = 1 << bit_in_block;
	newBits[block] = newBits[block] \| mask;
	}
	if (cp >= 0x10000 && cp <= 0x110000)
	{
	/* the spec says that bit 57 ("Non Plane 0") implies that there's
	at least one codepoint beyond the BMP; so I also include all
	the non-BMP codepoints here */
	newBits[1] = newBits[1] \| (1 << 25);
	}
	}

	for (unsigned int i = 0; i < 4; i++)
	ulUnicodeRange[i] = ulUnicodeRange[i] & newBits[i]; // set bits only if set in the original
	}

	/* https://github.com/Microsoft/Font-Validator/blob/520aaae/OTFontFileVal/val_OS2.cs#L644-L681
	* https://docs.microsoft.com/en-us/typography/legacy/legacy_arabic_fonts */
	enum font_page_t
	{
	FONT_PAGE_NONE = 0,
	FONT_PAGE_HEBREW = 0xB100, /* Hebrew Windows 3.1 font page */
	FONT_PAGE_SIMP_ARABIC = 0xB200, /* Simplified Arabic Windows 3.1 font page */
	FONT_PAGE_TRAD_ARABIC = 0xB300, /* Traditional Arabic Windows 3.1 font page */
	FONT_PAGE_OEM_ARABIC = 0xB400, /* OEM Arabic Windows 3.1 font page */
	FONT_PAGE_SIMP_FARSI = 0xBA00, /* Simplified Farsi Windows 3.1 font page */
	FONT_PAGE_TRAD_FARSI = 0xBB00, /* Traditional Farsi Windows 3.1 font page */
	FONT_PAGE_THAI = 0xDE00 /* Thai Windows 3.1 font page */
	};
	font_page_t get_font_page () const
	{ return (font_page_t) (version == 0 ? fsSelection & 0xFF00 : 0); }

	unsigned get_size () const
	{
	unsigned result = min_size;
	if (version >= 1) result += v1X.get_size ();
	if (version >= 2) result += v2X.get_size ();
	if (version >= 5) result += v5X.get_size ();
	return result;
	}

	bool sanitize (hb_sanitize_context_t *c) const
	{
	TRACE_SANITIZE (this);
	if (unlikely (!c->check_struct (this))) return_trace (false);
	if (unlikely (version >= 1 && !v1X.sanitize (c))) return_trace (false);
	if (unlikely (version >= 2 && !v2X.sanitize (c))) return_trace (false);
	if (unlikely (version >= 5 && !v5X.sanitize (c))) return_trace (false);
	return_trace (true);
	}

	public:
	HBUINT16 version;
	HBINT16 xAvgCharWidth;
	HBUINT16 usWeightClass;
	HBUINT16 usWidthClass;
	HBUINT16 fsType;
	HBINT16 ySubscriptXSize;
	HBINT16 ySubscriptYSize;
	HBINT16 ySubscriptXOffset;
	HBINT16 ySubscriptYOffset;
	HBINT16 ySuperscriptXSize;
	HBINT16 ySuperscriptYSize;
	HBINT16 ySuperscriptXOffset;
	HBINT16 ySuperscriptYOffset;
	HBINT16 yStrikeoutSize;
	HBINT16 yStrikeoutPosition;
	HBINT16 sFamilyClass;
	HBUINT8 panose[10];
	HBUINT32 ulUnicodeRange[4];
	Tag achVendID;
	HBUINT16 fsSelection;
	HBUINT16 usFirstCharIndex;
	HBUINT16 usLastCharIndex;
	HBINT16 sTypoAscender;
	HBINT16 sTypoDescender;
	HBINT16 sTypoLineGap;
	HBUINT16 usWinAscent;
	HBUINT16 usWinDescent;
	OS2V1Tail v1X;
	OS2V2Tail v2X;
	OS2V5Tail v5X;
	public:
	DEFINE_SIZE_MIN (78);
	};

	} /* namespace OT */


	#endif /* HB_OT_OS2_TABLE_HH */