third_party/harfbuzz-ng/src/hb-ot-layout-private.hh

   1 /*
   2  * Copyright © 2007,2008,2009  Red Hat, Inc.
   3  * Copyright © 2012  Google, Inc.
   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  * Red Hat Author(s): Behdad Esfahbod
  26  * Google Author(s): Behdad Esfahbod
  27  */
  28
  29 #ifndef HB_OT_LAYOUT_PRIVATE_HH
  30 #define HB_OT_LAYOUT_PRIVATE_HH
  31
  32 #include "hb-private.hh"
  33
  34 #include "hb-ot-layout.h"
  35
  36 #include "hb-font-private.hh"
  37 #include "hb-buffer-private.hh"
  38 #include "hb-set-private.hh"
  39
  40
  41 /* buffer var allocations, used during the GSUB/GPOS processing */
  42 #define glyph_props()           var1.u16[0] /* GDEF glyph properties */
  43 #define syllable()              var1.u8[2] /* GSUB/GPOS shaping boundaries */
  44 #define lig_props()             var1.u8[3] /* GSUB/GPOS ligature tracking */
  45
  46 /* buffer var allocations, used during the entire shaping process */
  47 #define unicode_props0()        var2.u8[0]
  48 #define unicode_props1()        var2.u8[1]
  49
  50
  51 inline void
  52 _hb_glyph_info_set_unicode_props (hb_glyph_info_t *info, hb_unicode_funcs_t *unicode)
  53 {
  54   info->unicode_props0() = ((unsigned int) unicode->general_category (info->codepoint)) |
  55                            (unicode->is_default_ignorable (info->codepoint) ? 0x80 : 0) |
  56                            (info->codepoint == 0x200C ? 0x40 : 0) |
  57                            (info->codepoint == 0x200D ? 0x20 : 0);
  58   info->unicode_props1() = unicode->modified_combining_class (info->codepoint);
  59 }
  60
  61 inline hb_unicode_general_category_t
  62 _hb_glyph_info_get_general_category (const hb_glyph_info_t *info)
  63 {
  64   return (hb_unicode_general_category_t) (info->unicode_props0() & 0x1F);
  65 }
  66
  67 inline void
  68 _hb_glyph_info_set_modified_combining_class (hb_glyph_info_t *info, unsigned int modified_class)
  69 {
  70   info->unicode_props1() = modified_class;
  71 }
  72
  73 inline unsigned int
  74 _hb_glyph_info_get_modified_combining_class (const hb_glyph_info_t *info)
  75 {
  76   return info->unicode_props1();
  77 }
  78
  79 inline hb_bool_t
  80 _hb_glyph_info_is_default_ignorable (const hb_glyph_info_t *info)
  81 {
  82   return !!(info->unicode_props0() & 0x80);
  83 }
  84
  85 inline hb_bool_t
  86 _hb_glyph_info_is_zwnj (const hb_glyph_info_t *info)
  87 {
  88   return !!(info->unicode_props0() & 0x40);
  89 }
  90
  91 inline hb_bool_t
  92 _hb_glyph_info_is_zwj (const hb_glyph_info_t *info)
  93 {
  94   return !!(info->unicode_props0() & 0x20);
  95 }
  96
  97
  98 #define hb_ot_layout_from_face(face) ((hb_ot_layout_t *) face->shaper_data.ot)
  99
 100 /*
 101  * GDEF
 102  */
 103
 104 typedef enum {
 105   HB_OT_LAYOUT_GLYPH_PROPS_UNCLASSIFIED = 1 << HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED,
 106   HB_OT_LAYOUT_GLYPH_PROPS_BASE_GLYPH   = 1 << HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH,
 107   HB_OT_LAYOUT_GLYPH_PROPS_LIGATURE     = 1 << HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE,
 108   HB_OT_LAYOUT_GLYPH_PROPS_MARK         = 1 << HB_OT_LAYOUT_GLYPH_CLASS_MARK,
 109   HB_OT_LAYOUT_GLYPH_PROPS_COMPONENT    = 1 << HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT
 110 } hb_ot_layout_glyph_class_mask_t;
 111
 112
 113
 114 /*
 115  * GSUB/GPOS
 116  */
 117
 118 /* lig_id / lig_comp
 119  *
 120  * When a ligature is formed:
 121  *
 122  *   - The ligature glyph and any marks in between all the same newly allocated
 123  *     lig_id,
 124  *   - The ligature glyph will get lig_num_comps set to the number of components
 125  *   - The marks get lig_comp > 0, reflecting which component of the ligature
 126  *     they were applied to.
 127  *   - This is used in GPOS to attach marks to the right component of a ligature
 128  *     in MarkLigPos.
 129  *
 130  * When a multiple-substitution is done:
 131  *
 132  *   - All resulting glyphs will have lig_id = 0,
 133  *   - The resulting glyphs will have lig_comp = 0, 1, 2, ... respectively.
 134  *   - This is used in GPOS to attach marks to the first component of a
 135  *     multiple substitution in MarkBasePos.
 136  *
 137  * The numbers are also used in GPOS to do mark-to-mark positioning only
 138  * to marks that belong to the same component of a ligature in MarkMarPos.
 139  */
 140 #define IS_LIG_BASE 0x10
 141 static inline void
 142 set_lig_props_for_ligature (hb_glyph_info_t &info, unsigned int lig_id, unsigned int lig_num_comps)
 143 {
 144   info.lig_props() = (lig_id << 5) | IS_LIG_BASE | (lig_num_comps & 0x0F);
 145 }
 146 static inline void
 147 set_lig_props_for_mark (hb_glyph_info_t &info, unsigned int lig_id, unsigned int lig_comp)
 148 {
 149   info.lig_props() = (lig_id << 5) | (lig_comp & 0x0F);
 150 }
 151 static inline void
 152 set_lig_props_for_component (hb_glyph_info_t &info, unsigned int comp)
 153 {
 154   set_lig_props_for_mark (info, 0, comp);
 155 }
 156
 157 static inline unsigned int
 158 get_lig_id (const hb_glyph_info_t &info)
 159 {
 160   return info.lig_props() >> 5;
 161 }
 162 static inline bool
 163 is_a_ligature (const hb_glyph_info_t &info)
 164 {
 165   return !!(info.lig_props() & IS_LIG_BASE);
 166 }
 167 static inline unsigned int
 168 get_lig_comp (const hb_glyph_info_t &info)
 169 {
 170   if (is_a_ligature (info))
 171     return 0;
 172   else
 173     return info.lig_props() & 0x0F;
 174 }
 175 static inline unsigned int
 176 get_lig_num_comps (const hb_glyph_info_t &info)
 177 {
 178   if ((info.glyph_props() & HB_OT_LAYOUT_GLYPH_PROPS_LIGATURE) && is_a_ligature (info))
 179     return info.lig_props() & 0x0F;
 180   else
 181     return 1;
 182 }
 183
 184 static inline uint8_t allocate_lig_id (hb_buffer_t *buffer) {
 185   uint8_t lig_id = buffer->next_serial () & 0x07;
 186   if (unlikely (!lig_id))
 187     lig_id = allocate_lig_id (buffer); /* in case of overflow */
 188   return lig_id;
 189 }
 190
 191
 192 HB_INTERNAL hb_bool_t
 193 hb_ot_layout_lookup_would_substitute_fast (hb_face_t            *face,
 194                                            unsigned int          lookup_index,
 195                                            const hb_codepoint_t *glyphs,
 196                                            unsigned int          glyphs_length,
 197                                            hb_bool_t             zero_context);
 198
 199
 200 /* Should be called before all the substitute_lookup's are done. */
 201 HB_INTERNAL void
 202 hb_ot_layout_substitute_start (hb_font_t    *font,
 203                                hb_buffer_t  *buffer);
 204
 205 HB_INTERNAL hb_bool_t
 206 hb_ot_layout_substitute_lookup (hb_font_t    *font,
 207                                 hb_buffer_t  *buffer,
 208                                 unsigned int  lookup_index,
 209                                 hb_mask_t     mask,
 210                                 hb_bool_t     auto_zwj);
 211
 212 /* Should be called after all the substitute_lookup's are done */
 213 HB_INTERNAL void
 214 hb_ot_layout_substitute_finish (hb_font_t    *font,
 215                                 hb_buffer_t  *buffer);
 216
 217
 218 /* Should be called before all the position_lookup's are done.  Resets positions to zero. */
 219 HB_INTERNAL void
 220 hb_ot_layout_position_start (hb_font_t    *font,
 221                              hb_buffer_t  *buffer);
 222
 223 HB_INTERNAL hb_bool_t
 224 hb_ot_layout_position_lookup (hb_font_t    *font,
 225                               hb_buffer_t  *buffer,
 226                               unsigned int  lookup_index,
 227                               hb_mask_t     mask,
 228                               hb_bool_t     auto_zwj);
 229
 230 /* Should be called after all the position_lookup's are done */
 231 HB_INTERNAL void
 232 hb_ot_layout_position_finish (hb_font_t    *font,
 233                               hb_buffer_t  *buffer);
 234
 235
 236
 237 /*
 238  * hb_ot_layout_t
 239  */
 240
 241 namespace OT {
 242   struct GDEF;
 243   struct GSUB;
 244   struct GPOS;
 245 }
 246
 247 struct hb_ot_layout_t
 248 {
 249   hb_blob_t *gdef_blob;
 250   hb_blob_t *gsub_blob;
 251   hb_blob_t *gpos_blob;
 252
 253   const struct OT::GDEF *gdef;
 254   const struct OT::GSUB *gsub;
 255   const struct OT::GPOS *gpos;
 256
 257   unsigned int gsub_lookup_count;
 258   unsigned int gpos_lookup_count;
 259
 260   hb_set_digest_t *gsub_digests;
 261   hb_set_digest_t *gpos_digests;
 262 };
 263
 264
 265 HB_INTERNAL hb_ot_layout_t *
 266 _hb_ot_layout_create (hb_face_t *face);
 267
 268 HB_INTERNAL void
 269 _hb_ot_layout_destroy (hb_ot_layout_t *layout);
 270
 271
 272
 273 #endif /* HB_OT_LAYOUT_PRIVATE_HH */