kc3-lang/harfbuzz/src/hb-ot-shape-private.hh

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• Hash : 607feb7c
  Author :
  Date : 2013-02-14T07:43:13
  

  [OTLayout] Ignore default-ignorables when matching GSUB/GPOS
  
  When matching lookups, be smart about default-ignorable characters.
  In particular:
  
  Do nothing specific about ZWNJ, but for the other default-ignorables:
  
  If the lookup in question uses the ignorable character in a sequence,
  then match it as we used to do.  However, if the sequence match will
  fail because the default-ignorable blocked it, try skipping the
  ignorable character and continue.
  
  The most immediate thing it means is that if Lam-Alef forms a ligature,
  then Lam-ZWJ-Alef will do to.  Finally!
  
  One exception: when matching for GPOS, or for backtrack/lookahead of
  GSUB, we ignore ZWNJ too.  That's the right thing to do.
  
  It certainly is possible to build fonts that this feature will result
  in undesirable glyphs, but it's hard to think of a real-world case
  that that would happen.
  
  This *does* break Indic shaping right now, since Indic Unicode has
  specific rules for what ZWJ/ZWNJ mean, and skipping ZWJ is breaking
  those rules.  That will be fixed in upcoming commits.
  

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• src/hb-ot-shape-private.hh

• /*
   * Copyright © 2010  Google, Inc.
   *
   *  This is part of HarfBuzz, a text shaping library.
   *
   * Permission is hereby granted, without written agreement and without
   * license or royalty fees, to use, copy, modify, and distribute this
   * software and its documentation for any purpose, provided that the
   * above copyright notice and the following two paragraphs appear in
   * all copies of this software.
   *
   * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
   * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
   * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
   * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
   * DAMAGE.
   *
   * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
   * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
   * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
   * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
   * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
   *
   * Google Author(s): Behdad Esfahbod
   */
  
  #ifndef HB_OT_SHAPE_PRIVATE_HH
  #define HB_OT_SHAPE_PRIVATE_HH
  
  #include "hb-private.hh"
  
  #include "hb-ot-map-private.hh"
  
  
  
  
  
  struct hb_ot_shape_plan_t
  {
    hb_segment_properties_t props;
    const struct hb_ot_complex_shaper_t *shaper;
    hb_ot_map_t map;
    const void *data;
  
    inline void collect_lookups (hb_tag_t table_tag, hb_set_t *lookups) const
    {
      unsigned int table_index;
      switch (table_tag) {
        case HB_OT_TAG_GSUB: table_index = 0; break;
        case HB_OT_TAG_GPOS: table_index = 1; break;
        default: return;
      }
      map.collect_lookups (table_index, lookups);
    }
    inline void substitute (hb_font_t *font, hb_buffer_t *buffer) const { map.substitute (this, font, buffer); }
    inline void position (hb_font_t *font, hb_buffer_t *buffer) const { map.position (this, font, buffer); }
  
    void finish (void) { map.finish (); }
  };
  
  struct hb_ot_shape_planner_t
  {
    /* In the order that they are filled in. */
    hb_face_t *face;
    hb_segment_properties_t props;
    const struct hb_ot_complex_shaper_t *shaper;
    hb_ot_map_builder_t map;
  
    hb_ot_shape_planner_t (const hb_shape_plan_t *master_plan) :
  			 face (master_plan->face),
  			 props (master_plan->props),
  			 shaper (NULL),
  			 map (face, &props) {}
    ~hb_ot_shape_planner_t (void) { map.finish (); }
  
    inline void compile (hb_ot_shape_plan_t &plan)
    {
      plan.props = props;
      plan.shaper = shaper;
      map.compile (plan.map);
    }
  
    private:
    NO_COPY (hb_ot_shape_planner_t);
  };
  
  
  #endif /* HB_OT_SHAPE_PRIVATE_HH */
  

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