harfbuzz/src/hb-ot-shape.cc

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/*
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* Copyright (C) 2009,2010 Red Hat, Inc.
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* Copyright (C) 2010 Google, Inc.
*
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* 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.
*
* Red Hat Author(s): Behdad Esfahbod
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* Google Author(s): Behdad Esfahbod
*/
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#include "hb-ot-shape-private.h"
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#include "hb-open-type-private.hh"
#include "hb-ot-layout.h"
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HB_BEGIN_DECLS
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/* XXX vertical */
hb_tag_t default_features[] = {
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HB_TAG('c','a','l','t'),
HB_TAG('c','c','m','p'),
HB_TAG('c','l','i','g'),
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HB_TAG('c','s','w','h'),
HB_TAG('c','u','r','s'),
HB_TAG('k','e','r','n'),
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HB_TAG('l','i','g','a'),
HB_TAG('l','o','c','l'),
HB_TAG('m','a','r','k'),
HB_TAG('m','k','m','k'),
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HB_TAG('r','l','i','g')
};
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struct lookup_map {
unsigned int index;
hb_mask_t mask;
};
static void
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add_lookups (hb_face_t *face,
hb_tag_t table_tag,
unsigned int feature_index,
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hb_mask_t mask,
lookup_map *lookups,
unsigned int *num_lookups,
unsigned int room_lookups)
{
unsigned int i = room_lookups - *num_lookups;
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lookups += *num_lookups;
unsigned int *lookup_indices = (unsigned int *) lookups;
hb_ot_layout_feature_get_lookup_indexes (face, table_tag, feature_index, 0,
&i,
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lookup_indices);
*num_lookups += i;
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while (i--) {
lookups[i].mask = mask;
lookups[i].index = lookup_indices[i];
}
}
static int
cmp_lookups (const void *p1, const void *p2)
{
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const lookup_map *a = (const lookup_map *) p1;
const lookup_map *b = (const lookup_map *) p2;
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return a->index - b->index;
}
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#define MAX_FEATURES 100 /* FIXME */
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struct hb_mask_allocator_t {
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struct feature_info_t {
hb_tag_t tag;
unsigned int value;
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unsigned int seq;
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bool global;
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static int
cmp (const void *p1, const void *p2)
{
const feature_info_t *a = reinterpret_cast<const feature_info_t *>(p1);
const feature_info_t *b = reinterpret_cast<const feature_info_t *>(p2);
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if (a->tag != b->tag)
return a->tag < b->tag ? -1 : 1;
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return a->seq < b->seq ? -1 : 1;
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}
};
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struct feature_map_t {
hb_tag_t tag; /* should be first */
unsigned int index;
unsigned int shift;
hb_mask_t mask;
static int
cmp (const void *p1, const void *p2)
{
const feature_map_t *a = reinterpret_cast<const feature_map_t *>(p1);
const feature_map_t *b = reinterpret_cast<const feature_map_t *>(p2);
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return a->tag < b->tag ? -1 : a->tag > b->tag ? 1 : 0;
}
};
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hb_mask_allocator_t (void) : count (0) {}
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void add_feature (hb_tag_t tag,
unsigned int value,
bool global)
{
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feature_info_t *info = &infos[count++];
info->tag = tag;
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info->value = value;
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info->seq = count;
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info->global = global;
}
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void compile (hb_face_t *face,
hb_tag_t table_tag,
unsigned int script_index,
unsigned int language_index)
{
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global_mask = 0;
unsigned int next_bit = 1;
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if (!count)
return;
qsort (infos, count, sizeof (infos[0]), feature_info_t::cmp);
unsigned int j = 0;
for (unsigned int i = 1; i < count; i++)
if (infos[i].tag != infos[j].tag)
infos[++j] = infos[i];
else {
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if (infos[i].global)
infos[j] = infos[i];
else {
infos[j].global = infos[j].global && (infos[j].value == infos[i].value);
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infos[j].value = MAX (infos[j].value, infos[i].value);
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}
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}
count = j + 1;
/* Allocate bits now */
j = 0;
for (unsigned int i = 0; i < count; i++) {
const feature_info_t *info = &infos[i];
unsigned int bits_needed;
if (info->global && info->value == 1)
/* Uses the global bit */
bits_needed = 0;
else
bits_needed = _hb_bit_storage (info->value);
if (!info->value || next_bit + bits_needed > 8 * sizeof (hb_mask_t))
continue; /* Feature disabled, or not enough bits. */
unsigned int feature_index;
if (!hb_ot_layout_language_find_feature (face, table_tag, script_index, language_index,
info->tag, &feature_index))
continue;
feature_map_t *map = &maps[j++];
map->tag = info->tag;
map->index = feature_index;
if (info->global && info->value == 1) {
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/* Use the global bit */
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map->shift = 0;
map->mask = 1;
} else {
map->shift = next_bit;
map->mask = (1 << (next_bit + bits_needed)) - (1 << next_bit);
next_bit += bits_needed;
}
if (info->global && map->mask != 1)
global_mask |= map->mask;
}
count = j;
}
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hb_mask_t get_global_mask (void) { return global_mask; }
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const feature_map_t *get_features (unsigned int *num_features) const {
*num_features = count;
return maps;
}
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const feature_map_t *find_feature (hb_tag_t tag) const {
static const feature_map_t off_map = { HB_TAG_NONE, Index::NOT_FOUND_INDEX, 0, 0 };
const feature_map_t *map = (const feature_map_t *) bsearch (&tag, maps, count, sizeof (maps[0]), feature_map_t::cmp);
return map ? map : &off_map;
}
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private:
unsigned int count;
feature_info_t infos[MAX_FEATURES];
feature_map_t maps[MAX_FEATURES];
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hb_mask_t global_mask;
};
static void
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hb_ot_shape_setup_lookups (hb_ot_shape_context_t *c,
lookup_map *lookups,
unsigned int *num_lookups)
{
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hb_mask_allocator_t allocator;
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switch (c->original_direction) {
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case HB_DIRECTION_LTR:
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allocator.add_feature (HB_TAG ('l','t','r','a'), 1, true);
allocator.add_feature (HB_TAG ('l','t','r','m'), 1, true);
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break;
case HB_DIRECTION_RTL:
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allocator.add_feature (HB_TAG ('r','t','l','a'), 1, true);
allocator.add_feature (HB_TAG ('r','t','l','m'), 1, false);
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break;
case HB_DIRECTION_TTB:
case HB_DIRECTION_BTT:
default:
break;
}
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for (unsigned int i = 0; i < ARRAY_LENGTH (default_features); i++)
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allocator.add_feature (default_features[i], 1, true);
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/* complex */
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for (unsigned int i = 0; i < c->num_features; i++) {
const hb_feature_t *feature = &c->features[i];
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allocator.add_feature (feature->tag, feature->value, (feature->start == 0 && feature->end == (unsigned int) -1));
}
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/* Compile features */
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unsigned int script_index, language_index, feature_index;
unsigned int room_lookups;
hb_ot_layout_table_choose_script (c->face, c->table_tag,
hb_ot_tags_from_script (c->buffer->props.script),
&script_index);
hb_ot_layout_script_find_language (c->face, c->table_tag, script_index,
hb_ot_tag_from_language (c->buffer->props.language),
&language_index);
allocator.compile (c->face, c->table_tag, script_index, language_index);
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/* Gather lookup indices for features */
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room_lookups = *num_lookups;
*num_lookups = 0;
if (hb_ot_layout_language_get_required_feature_index (c->face, c->table_tag, script_index, language_index,
&feature_index))
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add_lookups (c->face, c->table_tag, feature_index, 1, lookups, num_lookups, room_lookups);
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const hb_mask_allocator_t::feature_map_t *map;
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unsigned int num_features;
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map = allocator.get_features (&num_features);
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for (unsigned i = 0; i < num_features; i++)
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add_lookups (c->face, c->table_tag, map[i].index, map[i].mask, lookups, num_lookups, room_lookups);
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/* Sort lookups and merge duplicates */
qsort (lookups, *num_lookups, sizeof (lookups[0]), cmp_lookups);
if (*num_lookups)
{
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unsigned int j = 0;
for (unsigned int i = 1; i < *num_lookups; i++)
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if (lookups[i].index != lookups[j].index)
lookups[++j] = lookups[i];
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else
lookups[j].mask |= lookups[i].mask;
j++;
*num_lookups = j;
}
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/* Set masks in buffer */
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hb_mask_t global_mask = allocator.get_global_mask ();
if (global_mask)
c->buffer->set_masks (global_mask, global_mask, 0, (unsigned int) -1);
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for (unsigned int i = 0; i < c->num_features; i++)
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{
hb_feature_t *feature = &c->features[i];
map = allocator.find_feature (feature->tag);
if (!(feature->start == 0 && feature->end == (unsigned int)-1))
c->buffer->set_masks (feature->value << map->shift, map->mask, feature->start, feature->end);
}
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/* complex */
}
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static void
hb_ot_substitute_complex (hb_ot_shape_context_t *c)
{
lookup_map lookups[1000]; /* FIXME */
unsigned int num_lookups = ARRAY_LENGTH (lookups);
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if (!hb_ot_layout_has_substitution (c->face))
return;
c->table_tag = HB_OT_TAG_GSUB;
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hb_ot_shape_setup_lookups (c, lookups, &num_lookups);
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for (unsigned int i = 0; i < num_lookups; i++)
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hb_ot_layout_substitute_lookup (c->face, c->buffer, lookups[i].index, lookups[i].mask);
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c->applied_substitute_complex = TRUE;
return;
}
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static void
hb_ot_position_complex (hb_ot_shape_context_t *c)
{
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lookup_map lookups[1000]; /* FIXME */
unsigned int num_lookups = ARRAY_LENGTH (lookups);
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if (!hb_ot_layout_has_positioning (c->face))
return;
c->table_tag = HB_OT_TAG_GPOS;
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hb_ot_shape_setup_lookups (c, lookups, &num_lookups);
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for (unsigned int i = 0; i < num_lookups; i++)
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hb_ot_layout_position_lookup (c->font, c->face, c->buffer, lookups[i].index, lookups[i].mask);
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hb_ot_layout_position_finish (c->font, c->face, c->buffer);
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c->applied_position_complex = TRUE;
return;
}
/* Main shaper */
/* Prepare */
static inline hb_bool_t
is_variation_selector (hb_codepoint_t unicode)
{
return unlikely ((unicode >= 0x180B && unicode <= 0x180D) || /* MONGOLIAN FREE VARIATION SELECTOR ONE..THREE */
(unicode >= 0xFE00 && unicode <= 0xFE0F) || /* VARIATION SELECTOR-1..16 */
(unicode >= 0xE0100 && unicode <= 0xE01EF)); /* VARIATION SELECTOR-17..256 */
}
static void
hb_form_clusters (hb_buffer_t *buffer)
{
unsigned int count = buffer->len;
for (unsigned int i = 1; i < count; i++)
if (buffer->unicode->v.get_general_category (buffer->info[i].codepoint) == HB_CATEGORY_NON_SPACING_MARK)
buffer->info[i].cluster = buffer->info[i - 1].cluster;
}
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static void
hb_ensure_native_direction (hb_buffer_t *buffer)
{
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hb_direction_t direction = buffer->props.direction;
/* TODO vertical */
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if (HB_DIRECTION_IS_HORIZONTAL (direction) &&
direction != _hb_script_get_horizontal_direction (buffer->props.script))
{
hb_buffer_reverse_clusters (buffer);
buffer->props.direction = HB_DIRECTION_REVERSE (buffer->props.direction);
}
}
/* Substitute */
static void
hb_mirror_chars (hb_buffer_t *buffer)
{
hb_unicode_get_mirroring_func_t get_mirroring = buffer->unicode->v.get_mirroring;
if (HB_DIRECTION_IS_FORWARD (buffer->props.direction))
return;
// map = allocator.find_feature (HB_TAG ('r','t','l','m'));
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++) {
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hb_codepoint_t codepoint = get_mirroring (buffer->info[i].codepoint);
if (likely (codepoint == buffer->info[i].codepoint))
;// buffer->info[i].mask |= map->mask;
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else
buffer->info[i].codepoint = codepoint;
}
}
static void
hb_map_glyphs (hb_font_t *font,
hb_face_t *face,
hb_buffer_t *buffer)
{
if (unlikely (!buffer->len))
return;
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buffer->clear_output ();
unsigned int count = buffer->len - 1;
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for (buffer->i = 0; buffer->i < count;) {
if (unlikely (is_variation_selector (buffer->info[buffer->i + 1].codepoint))) {
buffer->add_output_glyph (hb_font_get_glyph (font, face, buffer->info[buffer->i].codepoint, buffer->info[buffer->i + 1].codepoint));
buffer->i++;
} else {
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buffer->add_output_glyph (hb_font_get_glyph (font, face, buffer->info[buffer->i].codepoint, 0));
}
}
if (likely (buffer->i < buffer->len))
buffer->add_output_glyph (hb_font_get_glyph (font, face, buffer->info[buffer->i].codepoint, 0));
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buffer->swap ();
}
static void
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hb_substitute_default (hb_ot_shape_context_t *c)
{
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hb_map_glyphs (c->font, c->face, c->buffer);
}
static void
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hb_substitute_complex_fallback (hb_ot_shape_context_t *c HB_UNUSED)
{
/* TODO Arabic */
}
/* Position */
static void
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hb_position_default (hb_ot_shape_context_t *c)
{
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hb_buffer_clear_positions (c->buffer);
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unsigned int count = c->buffer->len;
for (unsigned int i = 0; i < count; i++) {
hb_glyph_metrics_t metrics;
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hb_font_get_glyph_metrics (c->font, c->face, c->buffer->info[i].codepoint, &metrics);
c->buffer->pos[i].x_advance = metrics.x_advance;
c->buffer->pos[i].y_advance = metrics.y_advance;
}
}
static void
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hb_position_complex_fallback (hb_ot_shape_context_t *c HB_UNUSED)
{
/* TODO Mark pos */
}
static void
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hb_truetype_kern (hb_ot_shape_context_t *c)
{
/* TODO Check for kern=0 */
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unsigned int count = c->buffer->len;
for (unsigned int i = 1; i < count; i++) {
hb_position_t kern, kern1, kern2;
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kern = hb_font_get_kerning (c->font, c->face, c->buffer->info[i - 1].codepoint, c->buffer->info[i].codepoint);
kern1 = kern >> 1;
kern2 = kern - kern1;
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c->buffer->pos[i - 1].x_advance += kern1;
c->buffer->pos[i].x_advance += kern2;
c->buffer->pos[i].x_offset += kern2;
}
}
static void
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hb_position_complex_fallback_visual (hb_ot_shape_context_t *c)
{
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hb_truetype_kern (c);
}
/* Do it! */
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static void
hb_ot_shape_internal (hb_ot_shape_context_t *c)
{
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hb_form_clusters (c->buffer);
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/* SUBSTITUTE */
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{
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c->buffer->clear_masks ();
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/* Mirroring needs to see the original direction */
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hb_mirror_chars (c->buffer);
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hb_ensure_native_direction (c->buffer);
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hb_substitute_default (c);
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hb_ot_substitute_complex (c);
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if (!c->applied_substitute_complex)
hb_substitute_complex_fallback (c);
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}
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/* POSITION */
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{
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c->buffer->clear_masks ();
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hb_position_default (c);
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hb_ot_position_complex (c);
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hb_bool_t position_fallback = !c->applied_position_complex;
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if (position_fallback)
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hb_position_complex_fallback (c);
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if (HB_DIRECTION_IS_BACKWARD (c->buffer->props.direction))
hb_buffer_reverse (c->buffer);
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if (position_fallback)
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hb_position_complex_fallback_visual (c);
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}
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c->buffer->props.direction = c->original_direction;
}
void
hb_ot_shape (hb_font_t *font,
hb_face_t *face,
hb_buffer_t *buffer,
hb_feature_t *features,
unsigned int num_features)
{
hb_ot_shape_context_t c = {font, face, buffer, features, num_features};
/* Setup transient context members */
c.original_direction = buffer->props.direction;
hb_ot_shape_internal (&c);
}
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HB_END_DECLS