gfx/harfbuzz/src/hb-ot-var-avar-table.hh

   1 /*
   2  * Copyright © 2017  Google, Inc.
   3  *
   4  *  This is part of HarfBuzz, a text shaping library.
   5  *
   6  * Permission is hereby granted, without written agreement and without
   7  * license or royalty fees, to use, copy, modify, and distribute this
   8  * software and its documentation for any purpose, provided that the
   9  * above copyright notice and the following two paragraphs appear in
  10  * all copies of this software.
  11  *
  12  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  13  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  14  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  15  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  16  * DAMAGE.
  17  *
  18  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  19  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  20  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  21  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  22  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  23  *
  24  * Google Author(s): Behdad Esfahbod
  25  */
  26
  27 #ifndef HB_OT_VAR_AVAR_TABLE_HH
  28 #define HB_OT_VAR_AVAR_TABLE_HH
  29
  30 #include "hb-open-type.hh"
  31 #include "hb-ot-var-common.hh"
  32
  33
  34 /*
  35  * avar -- Axis Variations
  36  * https://docs.microsoft.com/en-us/typography/opentype/spec/avar
  37  */
  38
  39 #define HB_OT_TAG_avar HB_TAG('a','v','a','r')
  40
  41
  42 namespace OT {
  43
  44
  45 /* "Spec": https://github.com/be-fonts/boring-expansion-spec/issues/14 */
  46 struct avarV2Tail
  47 {
  48   friend struct avar;
  49
  50   bool sanitize (hb_sanitize_context_t *c,
  51                  const void *base) const
  52   {
  53     TRACE_SANITIZE (this);
  54     return_trace (varIdxMap.sanitize (c, base) &&
  55                   varStore.sanitize (c, base));
  56   }
  57
  58   protected:
  59   Offset32To<DeltaSetIndexMap>  varIdxMap;      /* Offset from the beginning of 'avar' table. */
  60   Offset32To<VariationStore>    varStore;       /* Offset from the beginning of 'avar' table. */
  61
  62   public:
  63   DEFINE_SIZE_STATIC (8);
  64 };
  65
  66
  67 struct AxisValueMap
  68 {
  69   bool sanitize (hb_sanitize_context_t *c) const
  70   {
  71     TRACE_SANITIZE (this);
  72     return_trace (c->check_struct (this));
  73   }
  74
  75   void set_mapping (float from_coord, float to_coord)
  76   {
  77     coords[0].set_float (from_coord);
  78     coords[1].set_float (to_coord);
  79   }
  80
  81   bool is_outside_axis_range (const Triple& axis_range) const
  82   {
  83     float from_coord = coords[0].to_float ();
  84     return !axis_range.contains (from_coord);
  85   }
  86
  87   bool must_include () const
  88   {
  89     float from_coord = coords[0].to_float ();
  90     float to_coord = coords[1].to_float ();
  91     return (from_coord == -1.f && to_coord == -1.f) ||
  92            (from_coord == 0.f && to_coord == 0.f) ||
  93            (from_coord == 1.f && to_coord == 1.f);
  94   }
  95
  96   void instantiate (const Triple& axis_range,
  97                     const Triple& unmapped_range,
  98                     const TripleDistances& triple_distances)
  99   {
 100     float from_coord = coords[0].to_float ();
 101     float to_coord = coords[1].to_float ();
 102
 103     from_coord = renormalizeValue (from_coord, unmapped_range, triple_distances);
 104     to_coord = renormalizeValue (to_coord, axis_range, triple_distances);
 105
 106     coords[0].set_float (from_coord);
 107     coords[1].set_float (to_coord);
 108   }
 109
 110   HB_INTERNAL static int cmp (const void *pa, const void *pb)
 111   {
 112     const AxisValueMap *a = (const AxisValueMap *) pa;
 113     const AxisValueMap *b = (const AxisValueMap *) pb;
 114
 115     int a_from = a->coords[0].to_int ();
 116     int b_from = b->coords[0].to_int ();
 117     if (a_from != b_from)
 118       return a_from - b_from;
 119
 120     /* this should never be reached. according to the spec, all of the axis
 121      * value map records for a given axis must have different fromCoord values
 122      * */
 123     int a_to = a->coords[1].to_int ();
 124     int b_to = b->coords[1].to_int ();
 125     return a_to - b_to;
 126   }
 127
 128   bool serialize (hb_serialize_context_t *c) const
 129   {
 130     TRACE_SERIALIZE (this);
 131     return_trace (c->embed (this));
 132   }
 133
 134   public:
 135   F2DOT14       coords[2];
 136 //   F2DOT14    fromCoord;      /* A normalized coordinate value obtained using
 137 //                               * default normalization. */
 138 //   F2DOT14    toCoord;        /* The modified, normalized coordinate value. */
 139
 140   public:
 141   DEFINE_SIZE_STATIC (4);
 142 };
 143
 144 struct SegmentMaps : Array16Of<AxisValueMap>
 145 {
 146   int map (int value, unsigned int from_offset = 0, unsigned int to_offset = 1) const
 147   {
 148 #define fromCoord coords[from_offset].to_int ()
 149 #define toCoord coords[to_offset].to_int ()
 150     /* The following special-cases are not part of OpenType, which requires
 151      * that at least -1, 0, and +1 must be mapped. But we include these as
 152      * part of a better error recovery scheme. */
 153     if (len < 2)
 154     {
 155       if (!len)
 156         return value;
 157       else /* len == 1*/
 158         return value - arrayZ[0].fromCoord + arrayZ[0].toCoord;
 159     }
 160
 161     if (value <= arrayZ[0].fromCoord)
 162       return value - arrayZ[0].fromCoord + arrayZ[0].toCoord;
 163
 164     unsigned int i;
 165     unsigned int count = len - 1;
 166     for (i = 1; i < count && value > arrayZ[i].fromCoord; i++)
 167       ;
 168
 169     if (value >= arrayZ[i].fromCoord)
 170       return value - arrayZ[i].fromCoord + arrayZ[i].toCoord;
 171
 172     if (unlikely (arrayZ[i-1].fromCoord == arrayZ[i].fromCoord))
 173       return arrayZ[i-1].toCoord;
 174
 175     int denom = arrayZ[i].fromCoord - arrayZ[i-1].fromCoord;
 176     return roundf (arrayZ[i-1].toCoord + ((float) (arrayZ[i].toCoord - arrayZ[i-1].toCoord) *
 177                                           (value - arrayZ[i-1].fromCoord)) / denom);
 178 #undef toCoord
 179 #undef fromCoord
 180   }
 181
 182   int unmap (int value) const { return map (value, 1, 0); }
 183
 184   Triple unmap_axis_range (const Triple& axis_range) const
 185   {
 186     F2DOT14 val, unmapped_val;
 187
 188     val.set_float (axis_range.minimum);
 189     unmapped_val.set_int (unmap (val.to_int ()));
 190     float unmapped_min = unmapped_val.to_float ();
 191
 192     val.set_float (axis_range.middle);
 193     unmapped_val.set_int (unmap (val.to_int ()));
 194     float unmapped_middle = unmapped_val.to_float ();
 195
 196     val.set_float (axis_range.maximum);
 197     unmapped_val.set_int (unmap (val.to_int ()));
 198     float unmapped_max = unmapped_val.to_float ();
 199
 200     return Triple{unmapped_min, unmapped_middle, unmapped_max};
 201   }
 202
 203   bool subset (hb_subset_context_t *c, hb_tag_t axis_tag) const
 204   {
 205     TRACE_SUBSET (this);
 206     /* avar mapped normalized axis range*/
 207     Triple *axis_range;
 208     if (!c->plan->axes_location.has (axis_tag, &axis_range))
 209       return c->serializer->embed (*this);
 210
 211     TripleDistances *axis_triple_distances;
 212     if (!c->plan->axes_triple_distances.has (axis_tag, &axis_triple_distances))
 213       return_trace (false);
 214
 215     auto *out = c->serializer->start_embed (this);
 216     if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
 217
 218     Triple unmapped_range = unmap_axis_range (*axis_range);
 219
 220     /* create a vector of retained mappings and sort */
 221     hb_vector_t<AxisValueMap> value_mappings;
 222     for (const auto& _ : as_array ())
 223     {
 224       if (_.is_outside_axis_range (unmapped_range))
 225         continue;
 226       AxisValueMap mapping;
 227       mapping = _;
 228       mapping.instantiate (*axis_range, unmapped_range, *axis_triple_distances);
 229       /* (-1, -1), (0, 0), (1, 1) mappings will be added later, so avoid
 230        * duplicates here */
 231       if (mapping.must_include ())
 232         continue;
 233       value_mappings.push (std::move (mapping));
 234     }
 235
 236     AxisValueMap m;
 237     m.set_mapping (-1.f, -1.f);
 238     value_mappings.push (m);
 239
 240     m.set_mapping (0.f, 0.f);
 241     value_mappings.push (m);
 242
 243     m.set_mapping (1.f, 1.f);
 244     value_mappings.push (m);
 245
 246     value_mappings.qsort ();
 247
 248     for (const auto& _ : value_mappings)
 249     {
 250       if (!_.serialize (c->serializer))
 251         return_trace (false);
 252     }
 253     return_trace (c->serializer->check_assign (out->len, value_mappings.length, HB_SERIALIZE_ERROR_INT_OVERFLOW));
 254   }
 255
 256   public:
 257   DEFINE_SIZE_ARRAY (2, *this);
 258 };
 259
 260 struct avar
 261 {
 262   static constexpr hb_tag_t tableTag = HB_OT_TAG_avar;
 263
 264   bool has_data () const { return version.to_int (); }
 265
 266   const SegmentMaps* get_segment_maps () const
 267   { return &firstAxisSegmentMaps; }
 268
 269   unsigned get_axis_count () const
 270   { return axisCount; }
 271
 272   bool sanitize (hb_sanitize_context_t *c) const
 273   {
 274     TRACE_SANITIZE (this);
 275     if (!(version.sanitize (c) &&
 276           hb_barrier () &&
 277           (version.major == 1
 278 #ifndef HB_NO_AVAR2
 279            || version.major == 2
 280 #endif
 281            ) &&
 282           c->check_struct (this)))
 283       return_trace (false);
 284
 285     const SegmentMaps *map = &firstAxisSegmentMaps;
 286     unsigned int count = axisCount;
 287     for (unsigned int i = 0; i < count; i++)
 288     {
 289       if (unlikely (!map->sanitize (c)))
 290         return_trace (false);
 291       map = &StructAfter<SegmentMaps> (*map);
 292     }
 293
 294 #ifndef HB_NO_AVAR2
 295     if (version.major < 2)
 296       return_trace (true);
 297     hb_barrier ();
 298
 299     const auto &v2 = * (const avarV2Tail *) map;
 300     if (unlikely (!v2.sanitize (c, this)))
 301       return_trace (false);
 302 #endif
 303
 304     return_trace (true);
 305   }
 306
 307   void map_coords (int *coords, unsigned int coords_length) const
 308   {
 309     unsigned int count = hb_min (coords_length, axisCount);
 310
 311     const SegmentMaps *map = &firstAxisSegmentMaps;
 312     for (unsigned int i = 0; i < count; i++)
 313     {
 314       coords[i] = map->map (coords[i]);
 315       map = &StructAfter<SegmentMaps> (*map);
 316     }
 317
 318 #ifndef HB_NO_AVAR2
 319     if (version.major < 2)
 320       return;
 321     hb_barrier ();
 322
 323     for (; count < axisCount; count++)
 324       map = &StructAfter<SegmentMaps> (*map);
 325
 326     const auto &v2 = * (const avarV2Tail *) map;
 327
 328     const auto &varidx_map = this+v2.varIdxMap;
 329     const auto &var_store = this+v2.varStore;
 330     auto *var_store_cache = var_store.create_cache ();
 331
 332     hb_vector_t<int> out;
 333     out.alloc (coords_length);
 334     for (unsigned i = 0; i < coords_length; i++)
 335     {
 336       int v = coords[i];
 337       uint32_t varidx = varidx_map.map (i);
 338       float delta = var_store.get_delta (varidx, coords, coords_length, var_store_cache);
 339       v += roundf (delta);
 340       v = hb_clamp (v, -(1<<14), +(1<<14));
 341       out.push (v);
 342     }
 343     for (unsigned i = 0; i < coords_length; i++)
 344       coords[i] = out[i];
 345
 346     OT::VariationStore::destroy_cache (var_store_cache);
 347 #endif
 348   }
 349
 350   void unmap_coords (int *coords, unsigned int coords_length) const
 351   {
 352     unsigned int count = hb_min (coords_length, axisCount);
 353
 354     const SegmentMaps *map = &firstAxisSegmentMaps;
 355     for (unsigned int i = 0; i < count; i++)
 356     {
 357       coords[i] = map->unmap (coords[i]);
 358       map = &StructAfter<SegmentMaps> (*map);
 359     }
 360   }
 361
 362   bool subset (hb_subset_context_t *c) const
 363   {
 364     TRACE_SUBSET (this);
 365     unsigned retained_axis_count = c->plan->axes_index_map.get_population ();
 366     if (!retained_axis_count) //all axes are pinned/dropped
 367       return_trace (false);
 368
 369     avar *out = c->serializer->allocate_min<avar> ();
 370     if (unlikely (!out)) return_trace (false);
 371
 372     out->version.major = 1;
 373     out->version.minor = 0;
 374     if (!c->serializer->check_assign (out->axisCount, retained_axis_count, HB_SERIALIZE_ERROR_INT_OVERFLOW))
 375       return_trace (false);
 376
 377     const hb_map_t& axes_index_map = c->plan->axes_index_map;
 378     const SegmentMaps *map = &firstAxisSegmentMaps;
 379     unsigned count = axisCount;
 380     for (unsigned int i = 0; i < count; i++)
 381     {
 382       if (axes_index_map.has (i))
 383       {
 384         hb_tag_t *axis_tag;
 385         if (!c->plan->axes_old_index_tag_map.has (i, &axis_tag))
 386           return_trace (false);
 387         if (!map->subset (c, *axis_tag))
 388           return_trace (false);
 389       }
 390       map = &StructAfter<SegmentMaps> (*map);
 391     }
 392     return_trace (true);
 393   }
 394
 395   protected:
 396   FixedVersion<>version;        /* Version of the avar table
 397                                  * initially set to 0x00010000u */
 398   HBUINT16      reserved;       /* This field is permanently reserved. Set to 0. */
 399   HBUINT16      axisCount;      /* The number of variation axes in the font. This
 400                                  * must be the same number as axisCount in the
 401                                  * 'fvar' table. */
 402   SegmentMaps   firstAxisSegmentMaps;
 403
 404   public:
 405   DEFINE_SIZE_MIN (8);
 406 };
 407
 408 } /* namespace OT */
 409
 410
 411 #endif /* HB_OT_VAR_AVAR_TABLE_HH */