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