harfbuzz/src/hb-subset-plan.cc

191 lines
5.5 KiB
C++

/*
* Copyright © 2018 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): Garret Rieger, Roderick Sheeter
*/
#include "hb-subset-plan.hh"
#include "hb-map.hh"
#include "hb-set.hh"
#include "hb-ot-cmap-table.hh"
#include "hb-ot-glyf-table.hh"
static void
_add_gid_and_children (const OT::glyf::accelerator_t &glyf,
hb_codepoint_t gid,
hb_set_t *gids_to_retain)
{
if (hb_set_has (gids_to_retain, gid))
// Already visited this gid, ignore.
return;
hb_set_add (gids_to_retain, gid);
OT::glyf::CompositeGlyphHeader::Iterator composite;
if (glyf.get_composite (gid, &composite))
{
do
{
_add_gid_and_children (glyf, (hb_codepoint_t) composite.current->glyphIndex, gids_to_retain);
} while (composite.move_to_next());
}
}
static void
_gsub_closure (hb_face_t *face, hb_set_t *gids_to_retain)
{
hb_auto_t<hb_set_t> lookup_indices;
hb_ot_layout_collect_lookups (face,
HB_OT_TAG_GSUB,
nullptr,
nullptr,
nullptr,
&lookup_indices);
hb_ot_layout_lookups_substitute_closure (face,
&lookup_indices,
gids_to_retain);
}
static hb_set_t *
_populate_gids_to_retain (hb_face_t *face,
const hb_set_t *unicodes,
bool close_over_gsub,
hb_set_t *unicodes_to_retain,
hb_map_t *codepoint_to_glyph,
hb_vector_t<hb_codepoint_t> *glyphs)
{
OT::cmap::accelerator_t cmap;
OT::glyf::accelerator_t glyf;
cmap.init (face);
glyf.init (face);
hb_set_t *initial_gids_to_retain = hb_set_create ();
initial_gids_to_retain->add (0); // Not-def
hb_codepoint_t cp = HB_SET_VALUE_INVALID;
while (unicodes->next (&cp))
{
hb_codepoint_t gid;
if (!cmap.get_nominal_glyph (cp, &gid))
{
DEBUG_MSG(SUBSET, nullptr, "Drop U+%04X; no gid", cp);
continue;
}
unicodes_to_retain->add (cp);
codepoint_to_glyph->set (cp, gid);
initial_gids_to_retain->add (gid);
}
if (close_over_gsub)
// Add all glyphs needed for GSUB substitutions.
_gsub_closure (face, initial_gids_to_retain);
// Populate a full set of glyphs to retain by adding all referenced
// composite glyphs.
hb_codepoint_t gid = HB_SET_VALUE_INVALID;
hb_set_t *all_gids_to_retain = hb_set_create ();
while (initial_gids_to_retain->next (&gid))
{
_add_gid_and_children (glyf, gid, all_gids_to_retain);
}
hb_set_destroy (initial_gids_to_retain);
glyphs->alloc (all_gids_to_retain->get_population ());
gid = HB_SET_VALUE_INVALID;
while (all_gids_to_retain->next (&gid))
glyphs->push (gid);
glyf.fini ();
cmap.fini ();
return all_gids_to_retain;
}
static void
_create_old_gid_to_new_gid_map (const hb_vector_t<hb_codepoint_t> &glyphs,
hb_map_t *glyph_map)
{
for (unsigned int i = 0; i < glyphs.len; i++) {
glyph_map->set (glyphs[i], i);
}
}
/**
* hb_subset_plan_create:
* Computes a plan for subsetting the supplied face according
* to a provided input. The plan describes
* which tables and glyphs should be retained.
*
* Return value: New subset plan.
*
* Since: 1.7.5
**/
hb_subset_plan_t *
hb_subset_plan_create (hb_face_t *face,
hb_subset_input_t *input)
{
hb_subset_plan_t *plan = hb_object_create<hb_subset_plan_t> ();
plan->drop_hints = input->drop_hints;
plan->drop_layout = input->drop_layout;
plan->unicodes = hb_set_create();
plan->glyphs.init();
plan->source = hb_face_reference (face);
plan->dest = hb_face_builder_create ();
plan->codepoint_to_glyph = hb_map_create();
plan->glyph_map = hb_map_create();
plan->glyphset = _populate_gids_to_retain (face,
input->unicodes,
!plan->drop_layout,
plan->unicodes,
plan->codepoint_to_glyph,
&plan->glyphs);
_create_old_gid_to_new_gid_map (plan->glyphs,
plan->glyph_map);
return plan;
}
/**
* hb_subset_plan_destroy:
*
* Since: 1.7.5
**/
void
hb_subset_plan_destroy (hb_subset_plan_t *plan)
{
if (!hb_object_destroy (plan)) return;
hb_set_destroy (plan->unicodes);
plan->glyphs.fini();
hb_face_destroy (plan->source);
hb_face_destroy (plan->dest);
hb_map_destroy (plan->codepoint_to_glyph);
hb_map_destroy (plan->glyph_map);
hb_set_destroy (plan->glyphset);
free (plan);
}