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      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   enum { 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.len;
     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 */
     94