tor-browser

hb-graphite2.cc (12899B)

---

/*
* Copyright © 2011  Martin Hosken
* Copyright © 2011  SIL International
* Copyright © 2011,2012  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
*/

#include "hb.hh"

#ifdef HAVE_GRAPHITE2

#include "hb-shaper-impl.hh"

#include "hb-graphite2.h"

#include <graphite2/Segment.h>

#include "hb-ot-layout.h"


/**
* SECTION:hb-graphite2
* @title: hb-graphite2
* @short_description: Graphite2 integration
* @include: hb-graphite2.h
*
* Functions for using HarfBuzz with fonts that include Graphite features.
* 
* For Graphite features to work, you must be sure that HarfBuzz was compiled
* with the `graphite2` shaping engine enabled. Currently, the default is to
* not enable `graphite2` shaping.
**/


/*
* shaper face data
*/

typedef struct hb_graphite2_tablelist_t
{
 struct hb_graphite2_tablelist_t *next;
 hb_blob_t *blob;
 unsigned int tag;
} hb_graphite2_tablelist_t;

struct hb_graphite2_face_data_t
{
 hb_face_t *face;
 gr_face   *grface;
 hb_atomic_t<hb_graphite2_tablelist_t *> tlist;
};

static const void *hb_graphite2_get_table (const void *data, unsigned int tag, size_t *len)
{
 hb_graphite2_face_data_t *face_data = (hb_graphite2_face_data_t *) data;
 hb_graphite2_tablelist_t *tlist = face_data->tlist;

 hb_blob_t *blob = nullptr;

 for (hb_graphite2_tablelist_t *p = tlist; p; p = p->next)
   if (p->tag == tag) {
     blob = p->blob;
     break;
   }

 if (unlikely (!blob))
 {
   blob = face_data->face->reference_table (tag);

   hb_graphite2_tablelist_t *p = (hb_graphite2_tablelist_t *) hb_calloc (1, sizeof (hb_graphite2_tablelist_t));
   if (unlikely (!p)) {
     hb_blob_destroy (blob);
     return nullptr;
   }
   p->blob = blob;
   p->tag = tag;

retry:
   hb_graphite2_tablelist_t *tlist = face_data->tlist;
   p->next = tlist;

   if (unlikely (!face_data->tlist.cmpexch (tlist, p)))
     goto retry;
 }

 unsigned int tlen;
 const char *d = hb_blob_get_data (blob, &tlen);
 *len = tlen;
 return d;
}

hb_graphite2_face_data_t *
_hb_graphite2_shaper_face_data_create (hb_face_t *face)
{
 hb_blob_t *silf_blob = face->reference_table (HB_GRAPHITE2_TAG_SILF);
 /* Umm, we just reference the table to check whether it exists.
  * Maybe add better API for this? */
 if (!hb_blob_get_length (silf_blob))
 {
   hb_blob_destroy (silf_blob);
   return nullptr;
 }
 hb_blob_destroy (silf_blob);

 hb_graphite2_face_data_t *data = (hb_graphite2_face_data_t *) hb_calloc (1, sizeof (hb_graphite2_face_data_t));
 if (unlikely (!data))
   return nullptr;

 data->face = face;
 const gr_face_ops ops = {sizeof(gr_face_ops), &hb_graphite2_get_table, NULL};
 data->grface = gr_make_face_with_ops (data, &ops, gr_face_preloadAll);

 if (unlikely (!data->grface)) {
   hb_free (data);
   return nullptr;
 }

 return data;
}

void
_hb_graphite2_shaper_face_data_destroy (hb_graphite2_face_data_t *data)
{
 hb_graphite2_tablelist_t *tlist = data->tlist;

 while (tlist)
 {
   hb_graphite2_tablelist_t *old = tlist;
   hb_blob_destroy (tlist->blob);
   tlist = tlist->next;
   hb_free (old);
 }

 gr_face_destroy (data->grface);

 hb_free (data);
}

/**
* hb_graphite2_face_get_gr_face: (skip)
* @face: @hb_face_t to query
*
* Fetches the Graphite2 gr_face corresponding to the specified
* #hb_face_t face object.
*
* Return value: the gr_face found
*
* Since: 0.9.10
*/
gr_face *
hb_graphite2_face_get_gr_face (hb_face_t *face)
{
 const hb_graphite2_face_data_t *data = face->data.graphite2;
 return data ? data->grface : nullptr;
}


/*
* shaper font data
*/

struct hb_graphite2_font_data_t {};

hb_graphite2_font_data_t *
_hb_graphite2_shaper_font_data_create (hb_font_t *font HB_UNUSED)
{
 return (hb_graphite2_font_data_t *) HB_SHAPER_DATA_SUCCEEDED;
}

void
_hb_graphite2_shaper_font_data_destroy (hb_graphite2_font_data_t *data HB_UNUSED)
{
}

#ifndef HB_DISABLE_DEPRECATED
/**
* hb_graphite2_font_get_gr_font: (skip)
* @font: An #hb_font_t
*
* Always returns `NULL`. Use hb_graphite2_face_get_gr_face() instead.
*
* Return value: (nullable): Graphite2 font associated with @font.
*
* Since: 0.9.10
* Deprecated: 1.4.2
*/
gr_font *
hb_graphite2_font_get_gr_font (hb_font_t *font HB_UNUSED)
{
 return nullptr;
}
#endif


/*
* shaper
*/

struct hb_graphite2_cluster_t {
 unsigned int base_char;
 unsigned int num_chars;
 unsigned int base_glyph;
 unsigned int num_glyphs;
 unsigned int cluster;
 int advance;
};

hb_bool_t
_hb_graphite2_shape (hb_shape_plan_t    *shape_plan HB_UNUSED,
	     hb_font_t          *font,
	     hb_buffer_t        *buffer,
	     const hb_feature_t *features,
	     unsigned int        num_features)
{
 hb_face_t *face = font->face;
 gr_face *grface = face->data.graphite2->grface;

 const char *lang = hb_language_to_string (hb_buffer_get_language (buffer));
 const char *lang_end = lang ? strchr (lang, '-') : nullptr;
 int lang_len = lang_end ? lang_end - lang : -1;
 gr_feature_val *feats = gr_face_featureval_for_lang (grface, lang ? hb_tag_from_string (lang, lang_len) : 0);

 for (unsigned int i = 0; i < num_features; i++)
 {
   const gr_feature_ref *fref = gr_face_find_fref (grface, features[i].tag);
   if (fref)
     gr_fref_set_feature_value (fref, features[i].value, feats);
 }

 hb_direction_t direction = buffer->props.direction;
 hb_direction_t horiz_dir = hb_script_get_horizontal_direction (buffer->props.script);
 /* TODO vertical:
  * The only BTT vertical script is Ogham, but it's not clear to me whether OpenType
  * Ogham fonts are supposed to be implemented BTT or not.  Need to research that
  * first. */
 if ((HB_DIRECTION_IS_HORIZONTAL (direction) &&
      direction != horiz_dir && horiz_dir != HB_DIRECTION_INVALID) ||
     (HB_DIRECTION_IS_VERTICAL   (direction) &&
      direction != HB_DIRECTION_TTB))
 {
   hb_buffer_reverse_clusters (buffer);
   direction = HB_DIRECTION_REVERSE (direction);
 }

 gr_segment *seg = nullptr;
 const gr_slot *is;
 unsigned int ci = 0, ic = 0;
 int curradvx = 0, curradvy = 0;

 unsigned int scratch_size;
 hb_buffer_t::scratch_buffer_t *scratch = buffer->get_scratch_buffer (&scratch_size);

 uint32_t *chars = (uint32_t *) scratch;

 for (unsigned int i = 0; i < buffer->len; ++i)
   chars[i] = buffer->info[i].codepoint;

 seg = gr_make_seg (nullptr, grface,
	     HB_TAG_NONE, // https://github.com/harfbuzz/harfbuzz/issues/3439#issuecomment-1442650148
	     feats,
	     gr_utf32, chars, buffer->len,
	     2 | (direction == HB_DIRECTION_RTL ? 1 : 0));

 if (unlikely (!seg)) {
   if (feats) gr_featureval_destroy (feats);
   return false;
 }

 unsigned int glyph_count = gr_seg_n_slots (seg);
 if (unlikely (!glyph_count)) {
   if (feats) gr_featureval_destroy (feats);
   gr_seg_destroy (seg);
   buffer->len = 0;
   return true;
 }

 (void) buffer->ensure (glyph_count);
 scratch = buffer->get_scratch_buffer (&scratch_size);
 while ((DIV_CEIL (sizeof (hb_graphite2_cluster_t) * buffer->len, sizeof (*scratch)) +
  DIV_CEIL (sizeof (hb_codepoint_t) * glyph_count, sizeof (*scratch))) > scratch_size)
 {
   if (unlikely (!buffer->ensure (buffer->allocated * 2)))
   {
     if (feats) gr_featureval_destroy (feats);
     gr_seg_destroy (seg);
     return false;
   }
   scratch = buffer->get_scratch_buffer (&scratch_size);
 }

#define ALLOCATE_ARRAY(Type, name, len) \
 Type *name = (Type *) scratch; \
 do { \
   unsigned int _consumed = DIV_CEIL ((len) * sizeof (Type), sizeof (*scratch)); \
   assert (_consumed <= scratch_size); \
   scratch += _consumed; \
   scratch_size -= _consumed; \
 } while (0)

 ALLOCATE_ARRAY (hb_graphite2_cluster_t, clusters, buffer->len);
 ALLOCATE_ARRAY (hb_codepoint_t, gids, glyph_count);

#undef ALLOCATE_ARRAY

 hb_memset (clusters, 0, sizeof (clusters[0]) * buffer->len);

 hb_codepoint_t *pg = gids;
 clusters[0].cluster = buffer->info[0].cluster;
 unsigned int upem = hb_face_get_upem (face);
 float xscale = (float) font->x_scale / upem;
 float yscale = (float) font->y_scale / upem;
 yscale *= yscale / xscale;
 unsigned int curradv = 0;
 if (HB_DIRECTION_IS_BACKWARD (direction))
 {
   curradv = gr_slot_origin_X(gr_seg_first_slot(seg)) * xscale;
   clusters[0].advance = gr_seg_advance_X(seg) * xscale - curradv;
 }
 else
   clusters[0].advance = 0;
 for (is = gr_seg_first_slot (seg), ic = 0; is; is = gr_slot_next_in_segment (is), ic++)
 {
   unsigned int before = gr_slot_before (is);
   unsigned int after = gr_slot_after (is);
   *pg = gr_slot_gid (is);
   pg++;
   while (clusters[ci].base_char > before && ci)
   {
     clusters[ci-1].num_chars += clusters[ci].num_chars;
     clusters[ci-1].num_glyphs += clusters[ci].num_glyphs;
     clusters[ci-1].advance += clusters[ci].advance;
     ci--;
   }

   if (gr_slot_can_insert_before (is) && clusters[ci].num_chars && before >= clusters[ci].base_char + clusters[ci].num_chars)
   {
     hb_graphite2_cluster_t *c = clusters + ci + 1;
     c->base_char = clusters[ci].base_char + clusters[ci].num_chars;
     c->cluster = buffer->info[c->base_char].cluster;
     c->num_chars = before - c->base_char;
     c->base_glyph = ic;
     c->num_glyphs = 0;
     if (HB_DIRECTION_IS_BACKWARD (direction))
     {
c->advance = curradv - gr_slot_origin_X(is) * xscale;
curradv -= c->advance;
     }
     else
     {
auto origin_X = gr_slot_origin_X (is) * xscale;
c->advance = 0;
clusters[ci].advance += origin_X - curradv;
curradv = origin_X;
     }
     ci++;
   }
   clusters[ci].num_glyphs++;

   if (clusters[ci].base_char + clusters[ci].num_chars < after + 1)
clusters[ci].num_chars = after + 1 - clusters[ci].base_char;
 }

 if (HB_DIRECTION_IS_BACKWARD (direction))
   clusters[ci].advance += curradv;
 else
   clusters[ci].advance += gr_seg_advance_X(seg) * xscale - curradv;
 ci++;

 for (unsigned int i = 0; i < ci; ++i)
 {
   for (unsigned int j = 0; j < clusters[i].num_glyphs; ++j)
   {
     hb_glyph_info_t *info = &buffer->info[clusters[i].base_glyph + j];
     info->codepoint = gids[clusters[i].base_glyph + j];
     info->cluster = clusters[i].cluster;
     info->var1.i32 = clusters[i].advance;     // all glyphs in the cluster get the same advance
   }
 }
 buffer->len = glyph_count;

 /* Positioning. */
 unsigned int currclus = UINT_MAX;
 const hb_glyph_info_t *info = buffer->info;
 hb_glyph_position_t *pPos = hb_buffer_get_glyph_positions (buffer, nullptr);
 if (!HB_DIRECTION_IS_BACKWARD (direction))
 {
   curradvx = 0;
   for (is = gr_seg_first_slot (seg); is; pPos++, ++info, is = gr_slot_next_in_segment (is))
   {
     pPos->x_offset = gr_slot_origin_X (is) * xscale - curradvx;
     pPos->y_offset = gr_slot_origin_Y (is) * yscale - curradvy;
     if (info->cluster != currclus) {
pPos->x_advance = info->var1.i32;
curradvx += pPos->x_advance;
currclus = info->cluster;
     } else
pPos->x_advance = 0.;

     pPos->y_advance = gr_slot_advance_Y (is, grface, nullptr) * yscale;
     curradvy += pPos->y_advance;
   }
 }
 else
 {
   curradvx = gr_seg_advance_X(seg) * xscale;
   for (is = gr_seg_first_slot (seg); is; pPos++, info++, is = gr_slot_next_in_segment (is))
   {
     if (info->cluster != currclus)
     {
pPos->x_advance = info->var1.i32;
curradvx -= pPos->x_advance;
currclus = info->cluster;
     } else
pPos->x_advance = 0.;

     pPos->y_advance = gr_slot_advance_Y (is, grface, nullptr) * yscale;
     curradvy -= pPos->y_advance;
     pPos->x_offset = gr_slot_origin_X (is) * xscale - info->var1.i32 - curradvx + pPos->x_advance;
     pPos->y_offset = gr_slot_origin_Y (is) * yscale - curradvy;
   }
   hb_buffer_reverse_clusters (buffer);
 }

 if (feats) gr_featureval_destroy (feats);
 gr_seg_destroy (seg);

 buffer->clear_glyph_flags ();
 buffer->unsafe_to_break ();

 return true;
}


#endif