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      1 /*
      2  * Copyright  2011  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 #define HB_SHAPER fallback
     28 #include "hb-shaper-impl-private.hh"
     29 
     30 
     31 HB_SHAPER_DATA_ENSURE_DEFINE(fallback, face)
     32 HB_SHAPER_DATA_ENSURE_DEFINE(fallback, font)
     33 
     34 
     35 /*
     36  * shaper face data
     37  */
     38 
     39 struct hb_fallback_shaper_face_data_t {};
     40 
     41 hb_fallback_shaper_face_data_t *
     42 _hb_fallback_shaper_face_data_create (hb_face_t *face HB_UNUSED)
     43 {
     44   return (hb_fallback_shaper_face_data_t *) HB_SHAPER_DATA_SUCCEEDED;
     45 }
     46 
     47 void
     48 _hb_fallback_shaper_face_data_destroy (hb_fallback_shaper_face_data_t *data HB_UNUSED)
     49 {
     50 }
     51 
     52 
     53 /*
     54  * shaper font data
     55  */
     56 
     57 struct hb_fallback_shaper_font_data_t {};
     58 
     59 hb_fallback_shaper_font_data_t *
     60 _hb_fallback_shaper_font_data_create (hb_font_t *font HB_UNUSED)
     61 {
     62   return (hb_fallback_shaper_font_data_t *) HB_SHAPER_DATA_SUCCEEDED;
     63 }
     64 
     65 void
     66 _hb_fallback_shaper_font_data_destroy (hb_fallback_shaper_font_data_t *data HB_UNUSED)
     67 {
     68 }
     69 
     70 
     71 /*
     72  * shaper shape_plan data
     73  */
     74 
     75 struct hb_fallback_shaper_shape_plan_data_t {};
     76 
     77 hb_fallback_shaper_shape_plan_data_t *
     78 _hb_fallback_shaper_shape_plan_data_create (hb_shape_plan_t    *shape_plan HB_UNUSED,
     79 					    const hb_feature_t *user_features HB_UNUSED,
     80 					    unsigned int        num_user_features HB_UNUSED,
     81 					    const int          *coords HB_UNUSED,
     82 					    unsigned int        num_coords HB_UNUSED)
     83 {
     84   return (hb_fallback_shaper_shape_plan_data_t *) HB_SHAPER_DATA_SUCCEEDED;
     85 }
     86 
     87 void
     88 _hb_fallback_shaper_shape_plan_data_destroy (hb_fallback_shaper_shape_plan_data_t *data HB_UNUSED)
     89 {
     90 }
     91 
     92 
     93 /*
     94  * shaper
     95  */
     96 
     97 hb_bool_t
     98 _hb_fallback_shape (hb_shape_plan_t    *shape_plan HB_UNUSED,
     99 		    hb_font_t          *font,
    100 		    hb_buffer_t        *buffer,
    101 		    const hb_feature_t *features HB_UNUSED,
    102 		    unsigned int        num_features HB_UNUSED)
    103 {
    104   /* TODO
    105    *
    106    * - Apply fallback kern.
    107    * - Handle Variation Selectors?
    108    * - Apply normalization?
    109    *
    110    * This will make the fallback shaper into a dumb "TrueType"
    111    * shaper which many people unfortunately still request.
    112    */
    113 
    114   hb_codepoint_t space;
    115   bool has_space = (bool) font->get_nominal_glyph (' ', &space);
    116 
    117   buffer->clear_positions ();
    118 
    119   hb_direction_t direction = buffer->props.direction;
    120   hb_unicode_funcs_t *unicode = buffer->unicode;
    121   unsigned int count = buffer->len;
    122   hb_glyph_info_t *info = buffer->info;
    123   hb_glyph_position_t *pos = buffer->pos;
    124   for (unsigned int i = 0; i < count; i++)
    125   {
    126     if (has_space && unicode->is_default_ignorable (info[i].codepoint)) {
    127       info[i].codepoint = space;
    128       pos[i].x_advance = 0;
    129       pos[i].y_advance = 0;
    130       continue;
    131     }
    132     (void) font->get_nominal_glyph (info[i].codepoint, &info[i].codepoint);
    133     font->get_glyph_advance_for_direction (info[i].codepoint,
    134 					   direction,
    135 					   &pos[i].x_advance,
    136 					   &pos[i].y_advance);
    137     font->subtract_glyph_origin_for_direction (info[i].codepoint,
    138 					       direction,
    139 					       &pos[i].x_offset,
    140 					       &pos[i].y_offset);
    141   }
    142 
    143   if (HB_DIRECTION_IS_BACKWARD (direction))
    144     hb_buffer_reverse (buffer);
    145 
    146   buffer->safe_to_break_all ();
    147 
    148   return true;
    149 }
    150