gfx/harfbuzz/src/hb-ot-os2-table.hh

   1 /*
   2  * Copyright © 2011,2012  Google, Inc.
   3  * Copyright © 2018  Ebrahim Byagowi
   4  *
   5  *  This is part of HarfBuzz, a text shaping library.
   6  *
   7  * Permission is hereby granted, without written agreement and without
   8  * license or royalty fees, to use, copy, modify, and distribute this
   9  * software and its documentation for any purpose, provided that the
  10  * above copyright notice and the following two paragraphs appear in
  11  * all copies of this software.
  12  *
  13  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  14  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  15  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  16  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  17  * DAMAGE.
  18  *
  19  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  20  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  21  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  22  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  23  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  24  *
  25  * Google Author(s): Behdad Esfahbod
  26  */
  27
  28 #ifndef HB_OT_OS2_TABLE_HH
  29 #define HB_OT_OS2_TABLE_HH
  30
  31 #include "hb-open-type.hh"
  32 #include "hb-ot-os2-unicode-ranges.hh"
  33
  34 #include "hb-set.hh"
  35
  36 /*
  37  * OS/2 and Windows Metrics
  38  * https://docs.microsoft.com/en-us/typography/opentype/spec/os2
  39  */
  40 #define HB_OT_TAG_OS2 HB_TAG('O','S','/','2')
  41
  42
  43 namespace OT {
  44
  45 struct OS2V1Tail
  46 {
  47   bool sanitize (hb_sanitize_context_t *c) const
  48   {
  49     TRACE_SANITIZE (this);
  50     return_trace (c->check_struct (this));
  51   }
  52
  53   public:
  54   HBUINT32      ulCodePageRange1;
  55   HBUINT32      ulCodePageRange2;
  56   public:
  57   DEFINE_SIZE_STATIC (8);
  58 };
  59
  60 struct OS2V2Tail
  61 {
  62   bool has_data () const { return sxHeight || sCapHeight; }
  63
  64   const OS2V2Tail * operator -> () const { return this; }
  65
  66   bool sanitize (hb_sanitize_context_t *c) const
  67   {
  68     TRACE_SANITIZE (this);
  69     return_trace (c->check_struct (this));
  70   }
  71
  72   public:
  73   HBINT16       sxHeight;
  74   HBINT16       sCapHeight;
  75   HBUINT16      usDefaultChar;
  76   HBUINT16      usBreakChar;
  77   HBUINT16      usMaxContext;
  78   public:
  79   DEFINE_SIZE_STATIC (10);
  80 };
  81
  82 struct OS2V5Tail
  83 {
  84   inline bool get_optical_size (unsigned int *lower, unsigned int *upper) const
  85   {
  86     unsigned int lower_optical_size = usLowerOpticalPointSize;
  87     unsigned int upper_optical_size = usUpperOpticalPointSize;
  88
  89     /* Per https://docs.microsoft.com/en-us/typography/opentype/spec/os2#lps */
  90     if (lower_optical_size < upper_optical_size &&
  91         lower_optical_size >= 1 && lower_optical_size <= 0xFFFE &&
  92         upper_optical_size >= 2 && upper_optical_size <= 0xFFFF)
  93     {
  94       *lower = lower_optical_size;
  95       *upper = upper_optical_size;
  96       return true;
  97     }
  98     return false;
  99   }
 100
 101   bool sanitize (hb_sanitize_context_t *c) const
 102   {
 103     TRACE_SANITIZE (this);
 104     return_trace (c->check_struct (this));
 105   }
 106
 107   public:
 108   HBUINT16      usLowerOpticalPointSize;
 109   HBUINT16      usUpperOpticalPointSize;
 110   public:
 111   DEFINE_SIZE_STATIC (4);
 112 };
 113
 114 struct OS2
 115 {
 116   static constexpr hb_tag_t tableTag = HB_OT_TAG_OS2;
 117
 118   bool has_data () const { return usWeightClass || usWidthClass || usFirstCharIndex || usLastCharIndex; }
 119
 120   const OS2V1Tail &v1 () const { return version >= 1 ? v1X : Null (OS2V1Tail); }
 121   const OS2V2Tail &v2 () const { return version >= 2 ? v2X : Null (OS2V2Tail); }
 122   const OS2V5Tail &v5 () const { return version >= 5 ? v5X : Null (OS2V5Tail); }
 123
 124   enum selection_flag_t {
 125     ITALIC              = 1u<<0,
 126     UNDERSCORE          = 1u<<1,
 127     NEGATIVE            = 1u<<2,
 128     OUTLINED            = 1u<<3,
 129     STRIKEOUT           = 1u<<4,
 130     BOLD                = 1u<<5,
 131     REGULAR             = 1u<<6,
 132     USE_TYPO_METRICS    = 1u<<7,
 133     WWS                 = 1u<<8,
 134     OBLIQUE             = 1u<<9
 135   };
 136
 137   bool        is_italic () const { return fsSelection & ITALIC; }
 138   bool       is_oblique () const { return fsSelection & OBLIQUE; }
 139   bool use_typo_metrics () const { return fsSelection & USE_TYPO_METRICS; }
 140
 141   enum width_class_t {
 142     FWIDTH_ULTRA_CONDENSED      = 1, /* 50% */
 143     FWIDTH_EXTRA_CONDENSED      = 2, /* 62.5% */
 144     FWIDTH_CONDENSED            = 3, /* 75% */
 145     FWIDTH_SEMI_CONDENSED       = 4, /* 87.5% */
 146     FWIDTH_NORMAL               = 5, /* 100% */
 147     FWIDTH_SEMI_EXPANDED        = 6, /* 112.5% */
 148     FWIDTH_EXPANDED             = 7, /* 125% */
 149     FWIDTH_EXTRA_EXPANDED       = 8, /* 150% */
 150     FWIDTH_ULTRA_EXPANDED       = 9  /* 200% */
 151   };
 152
 153   float get_width () const
 154   {
 155     switch (usWidthClass) {
 156     case FWIDTH_ULTRA_CONDENSED:return 50.f;
 157     case FWIDTH_EXTRA_CONDENSED:return 62.5f;
 158     case FWIDTH_CONDENSED:      return 75.f;
 159     case FWIDTH_SEMI_CONDENSED: return 87.5f;
 160     default:
 161     case FWIDTH_NORMAL:         return 100.f;
 162     case FWIDTH_SEMI_EXPANDED:  return 112.5f;
 163     case FWIDTH_EXPANDED:       return 125.f;
 164     case FWIDTH_EXTRA_EXPANDED: return 150.f;
 165     case FWIDTH_ULTRA_EXPANDED: return 200.f;
 166     }
 167   }
 168
 169   bool subset (hb_subset_context_t *c) const
 170   {
 171     TRACE_SUBSET (this);
 172     OS2 *os2_prime = c->serializer->embed (this);
 173     if (unlikely (!os2_prime)) return_trace (false);
 174     if (c->plan->flags & HB_SUBSET_FLAGS_NO_PRUNE_UNICODE_RANGES)
 175       return_trace (true);
 176
 177     /* when --gids option is not used, no need to do collect_mapping that is
 178        * iterating all codepoints in each subtable, which is not efficient */
 179     uint16_t min_cp, max_cp;
 180     find_min_and_max_codepoint (c->plan->unicodes, &min_cp, &max_cp);
 181     os2_prime->usFirstCharIndex = min_cp;
 182     os2_prime->usLastCharIndex = max_cp;
 183
 184     _update_unicode_ranges (c->plan->unicodes, os2_prime->ulUnicodeRange);
 185
 186     return_trace (true);
 187   }
 188
 189   void _update_unicode_ranges (const hb_set_t *codepoints,
 190                                HBUINT32 ulUnicodeRange[4]) const
 191   {
 192     HBUINT32    newBits[4];
 193     for (unsigned int i = 0; i < 4; i++)
 194       newBits[i] = 0;
 195
 196     hb_codepoint_t cp = HB_SET_VALUE_INVALID;
 197     while (codepoints->next (&cp)) {
 198       unsigned int bit = _hb_ot_os2_get_unicode_range_bit (cp);
 199       if (bit < 128)
 200       {
 201         unsigned int block = bit / 32;
 202         unsigned int bit_in_block = bit % 32;
 203         unsigned int mask = 1 << bit_in_block;
 204         newBits[block] = newBits[block] | mask;
 205       }
 206       if (cp >= 0x10000 && cp <= 0x110000)
 207       {
 208         /* the spec says that bit 57 ("Non Plane 0") implies that there's
 209            at least one codepoint beyond the BMP; so I also include all
 210            the non-BMP codepoints here */
 211         newBits[1] = newBits[1] | (1 << 25);
 212       }
 213     }
 214
 215     for (unsigned int i = 0; i < 4; i++)
 216       ulUnicodeRange[i] = ulUnicodeRange[i] & newBits[i]; // set bits only if set in the original
 217   }
 218
 219   static void find_min_and_max_codepoint (const hb_set_t *codepoints,
 220                                           uint16_t *min_cp, /* OUT */
 221                                           uint16_t *max_cp  /* OUT */)
 222   {
 223     *min_cp = hb_min (0xFFFFu, codepoints->get_min ());
 224     *max_cp = hb_min (0xFFFFu, codepoints->get_max ());
 225   }
 226
 227   /* https://github.com/Microsoft/Font-Validator/blob/520aaae/OTFontFileVal/val_OS2.cs#L644-L681 */
 228   enum font_page_t
 229   {
 230     FONT_PAGE_HEBREW            = 0xB100, /* Hebrew Windows 3.1 font page */
 231     FONT_PAGE_SIMP_ARABIC       = 0xB200, /* Simplified Arabic Windows 3.1 font page */
 232     FONT_PAGE_TRAD_ARABIC       = 0xB300, /* Traditional Arabic Windows 3.1 font page */
 233     FONT_PAGE_OEM_ARABIC        = 0xB400, /* OEM Arabic Windows 3.1 font page */
 234     FONT_PAGE_SIMP_FARSI        = 0xBA00, /* Simplified Farsi Windows 3.1 font page */
 235     FONT_PAGE_TRAD_FARSI        = 0xBB00, /* Traditional Farsi Windows 3.1 font page */
 236     FONT_PAGE_THAI              = 0xDE00  /* Thai Windows 3.1 font page */
 237   };
 238   font_page_t get_font_page () const
 239   { return (font_page_t) (version == 0 ? fsSelection & 0xFF00 : 0); }
 240
 241   unsigned get_size () const
 242   {
 243     unsigned result = min_size;
 244     if (version >= 1) result += v1X.get_size ();
 245     if (version >= 2) result += v2X.get_size ();
 246     if (version >= 5) result += v5X.get_size ();
 247     return result;
 248   }
 249
 250   bool sanitize (hb_sanitize_context_t *c) const
 251   {
 252     TRACE_SANITIZE (this);
 253     if (unlikely (!c->check_struct (this))) return_trace (false);
 254     if (unlikely (version >= 1 && !v1X.sanitize (c))) return_trace (false);
 255     if (unlikely (version >= 2 && !v2X.sanitize (c))) return_trace (false);
 256     if (unlikely (version >= 5 && !v5X.sanitize (c))) return_trace (false);
 257     return_trace (true);
 258   }
 259
 260   public:
 261   HBUINT16      version;
 262   HBINT16       xAvgCharWidth;
 263   HBUINT16      usWeightClass;
 264   HBUINT16      usWidthClass;
 265   HBUINT16      fsType;
 266   HBINT16       ySubscriptXSize;
 267   HBINT16       ySubscriptYSize;
 268   HBINT16       ySubscriptXOffset;
 269   HBINT16       ySubscriptYOffset;
 270   HBINT16       ySuperscriptXSize;
 271   HBINT16       ySuperscriptYSize;
 272   HBINT16       ySuperscriptXOffset;
 273   HBINT16       ySuperscriptYOffset;
 274   HBINT16       yStrikeoutSize;
 275   HBINT16       yStrikeoutPosition;
 276   HBINT16       sFamilyClass;
 277   HBUINT8       panose[10];
 278   HBUINT32      ulUnicodeRange[4];
 279   Tag           achVendID;
 280   HBUINT16      fsSelection;
 281   HBUINT16      usFirstCharIndex;
 282   HBUINT16      usLastCharIndex;
 283   HBINT16       sTypoAscender;
 284   HBINT16       sTypoDescender;
 285   HBINT16       sTypoLineGap;
 286   HBUINT16      usWinAscent;
 287   HBUINT16      usWinDescent;
 288   OS2V1Tail     v1X;
 289   OS2V2Tail     v2X;
 290   OS2V5Tail     v5X;
 291   public:
 292   DEFINE_SIZE_MIN (78);
 293 };
 294
 295 } /* namespace OT */
 296
 297
 298 #endif /* HB_OT_OS2_TABLE_HH */