1 /*
   2  * Copyright © 2018  Ebrahim Byagowi
   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 #ifndef HB_AAT_LAYOUT_LCAR_TABLE_HH
  25 #define HB_AAT_LAYOUT_LCAR_TABLE_HH
  26 
  27 #include "hb-open-type.hh"
  28 #include "hb-aat-layout-common.hh"
  29 
  30 /*
  31  * lcar -- Ligature caret
  32  * https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6lcar.html
  33  */
  34 #define HB_AAT_TAG_lcar HB_TAG('l','c','a','r')
  35 
  36 
  37 namespace AAT {
  38 
  39 typedef ArrayOf<HBINT16> LigCaretClassEntry;
  40 
  41 struct lcar
  42 {
  43   static constexpr hb_tag_t tableTag = HB_AAT_TAG_lcar;
  44 
  45   unsigned int get_lig_carets (hb_font_t      *font,
  46                                hb_direction_t  direction,
  47                                hb_codepoint_t  glyph,
  48                                unsigned int    start_offset,
  49                                unsigned int   *caret_count /* IN/OUT */,
  50                                hb_position_t  *caret_array /* OUT */) const
  51   {
  52     const OffsetTo<LigCaretClassEntry>* entry_offset = lookup.get_value (glyph,
  53                                                                          font->face->get_num_glyphs ());
  54     const LigCaretClassEntry& array = entry_offset ? this+*entry_offset : Null (LigCaretClassEntry);
  55     if (caret_count)
  56     {
  57       hb_array_t<const HBINT16> arr = array.sub_array (start_offset, caret_count);
  58       unsigned int count = arr.length;
  59       for (unsigned int i = 0; i < count; ++i)
  60         switch (format)
  61         {
  62         case 0: caret_array[i] = font->em_scale_dir (arr[i], direction); break;
  63         case 1:
  64           hb_position_t x, y;
  65           font->get_glyph_contour_point_for_origin (glyph, arr[i], direction, &x, &y);
  66           caret_array[i] = HB_DIRECTION_IS_HORIZONTAL (direction) ? x : y;
  67           break;
  68         }
  69     }
  70     return array.len;
  71   }
  72 
  73   bool sanitize (hb_sanitize_context_t *c) const
  74   {
  75     TRACE_SANITIZE (this);
  76     return_trace (likely (c->check_struct (this) &&
  77                           version.major == 1 &&
  78                           lookup.sanitize (c, this)));
  79   }
  80 
  81   protected:
  82   FixedVersion<>version;        /* Version number of the ligature caret table */
  83   HBUINT16      format;         /* Format of the ligature caret table. */
  84   Lookup<OffsetTo<LigCaretClassEntry> >
  85                 lookup;         /* data Lookup table associating glyphs */
  86 
  87   public:
  88   DEFINE_SIZE_MIN (8);
  89 };
  90 
  91 } /* namespace AAT */
  92 
  93 #endif /* HB_AAT_LAYOUT_LCAR_TABLE_HH */