harfbuzz/src/hb-ot-shape.cc

479 lines
13 KiB
C++
Raw Normal View History

/*
* Copyright (C) 2009 Red Hat, Inc.
*
2010-04-22 06:11:43 +02:00
* 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
*/
2010-05-22 01:56:40 +02:00
#include "hb-ot-shape-private.hh"
#include "hb-buffer-private.hh"
#include "hb-ot-layout.h"
2010-05-21 18:59:04 +02:00
/* XXX vertical */
hb_tag_t default_features[] = {
2010-05-21 19:06:35 +02:00
HB_TAG('c','a','l','t'),
HB_TAG('c','c','m','p'),
HB_TAG('c','l','i','g'),
2010-05-21 19:06:35 +02:00
HB_TAG('c','s','w','h'),
HB_TAG('c','u','r','s'),
HB_TAG('k','e','r','n'),
2010-05-21 19:06:35 +02:00
HB_TAG('l','i','g','a'),
HB_TAG('l','o','c','l'),
HB_TAG('m','a','r','k'),
HB_TAG('m','k','m','k'),
2010-05-21 19:06:35 +02:00
HB_TAG('r','l','i','g')
};
2010-05-21 18:58:20 +02:00
enum {
MASK_ALWAYS_ON = 1 << 0,
MASK_RTLM = 1 << 1
};
#define MASK_BITS_USED 2
2010-05-20 16:14:44 +02:00
struct lookup_map {
unsigned int index;
hb_mask_t mask;
};
static void
add_feature (hb_face_t *face,
hb_tag_t table_tag,
unsigned int feature_index,
2010-05-20 16:14:44 +02:00
hb_mask_t mask,
lookup_map *lookups,
unsigned int *num_lookups,
unsigned int room_lookups)
{
unsigned int i = room_lookups - *num_lookups;
2010-05-20 16:14:44 +02:00
lookups += *num_lookups;
unsigned int *lookup_indices = (unsigned int *) lookups;
hb_ot_layout_feature_get_lookup_indexes (face, table_tag, feature_index, 0,
&i,
2010-05-20 16:14:44 +02:00
lookup_indices);
*num_lookups += i;
2010-05-20 16:14:44 +02:00
while (i--) {
lookups[i].mask = mask;
lookups[i].index = lookup_indices[i];
}
}
2010-05-21 18:53:10 +02:00
static hb_bool_t
maybe_add_feature (hb_face_t *face,
hb_tag_t table_tag,
unsigned int script_index,
unsigned int language_index,
hb_tag_t feature_tag,
hb_mask_t mask,
lookup_map *lookups,
unsigned int *num_lookups,
unsigned int room_lookups)
{
unsigned int feature_index;
if (hb_ot_layout_language_find_feature (face, table_tag, script_index, language_index,
feature_tag,
&feature_index))
{
add_feature (face, table_tag, feature_index, mask, lookups, num_lookups, room_lookups);
return TRUE;
}
return FALSE;
}
static int
cmp_lookups (const void *p1, const void *p2)
{
2010-05-20 16:14:44 +02:00
const lookup_map *a = (const lookup_map *) p1;
const lookup_map *b = (const lookup_map *) p2;
2010-05-20 16:14:44 +02:00
return a->index - b->index;
}
static void
2010-04-23 20:44:55 +02:00
setup_lookups (hb_face_t *face,
hb_buffer_t *buffer,
hb_feature_t *features,
unsigned int num_features,
hb_tag_t table_tag,
2010-05-20 16:14:44 +02:00
lookup_map *lookups,
2010-05-21 18:53:10 +02:00
unsigned int *num_lookups,
hb_direction_t original_direction)
{
unsigned int i, j, script_index, language_index, feature_index, room_lookups;
room_lookups = *num_lookups;
*num_lookups = 0;
hb_ot_layout_table_choose_script (face, table_tag,
hb_ot_tags_from_script (buffer->script),
&script_index);
hb_ot_layout_script_find_language (face, table_tag, script_index,
hb_ot_tag_from_language (buffer->language),
&language_index);
if (hb_ot_layout_language_get_required_feature_index (face, table_tag, script_index, language_index,
&feature_index))
2010-05-20 16:14:44 +02:00
add_feature (face, table_tag, feature_index, 1, lookups, num_lookups, room_lookups);
for (i = 0; i < ARRAY_LENGTH (default_features); i++)
2010-05-21 18:53:10 +02:00
maybe_add_feature (face, table_tag, script_index, language_index, default_features[i], 1, lookups, num_lookups, room_lookups);
switch (original_direction) {
case HB_DIRECTION_LTR:
maybe_add_feature (face, table_tag, script_index, language_index, HB_TAG ('l','t','r','a'), 1, lookups, num_lookups, room_lookups);
maybe_add_feature (face, table_tag, script_index, language_index, HB_TAG ('l','t','r','m'), 1, lookups, num_lookups, room_lookups);
break;
case HB_DIRECTION_RTL:
maybe_add_feature (face, table_tag, script_index, language_index, HB_TAG ('r','t','l','a'), 1, lookups, num_lookups, room_lookups);
break;
case HB_DIRECTION_TTB:
case HB_DIRECTION_BTT:
default:
break;
}
2010-05-21 18:58:20 +02:00
unsigned int next_bit = MASK_BITS_USED;
2010-05-21 18:31:45 +02:00
hb_mask_t global_mask = 0;
2010-05-20 14:40:18 +02:00
for (i = 0; i < num_features; i++)
{
2010-05-21 18:31:45 +02:00
hb_feature_t *feature = &features[i];
if (!hb_ot_layout_language_find_feature (face, table_tag, script_index, language_index,
2010-05-21 18:31:45 +02:00
feature->tag,
&feature_index))
continue;
2010-05-21 18:31:45 +02:00
if (feature->value == 1 && feature->start == 0 && feature->end == (unsigned int) -1) {
add_feature (face, table_tag, feature_index, 1, lookups, num_lookups, room_lookups);
2010-05-20 16:40:12 +02:00
continue;
2010-05-21 18:31:45 +02:00
}
/* Allocate bits for the features */
unsigned int bits_needed = _hb_bit_storage (feature->value);
if (!bits_needed)
continue; /* Feature disabled */
if (next_bit + bits_needed > 8 * sizeof (hb_mask_t))
continue; /* Oh well... */
unsigned int mask = (1 << (next_bit + bits_needed)) - (1 << next_bit);
unsigned int value = feature->value << next_bit;
next_bit += bits_needed;
2010-05-20 16:40:12 +02:00
add_feature (face, table_tag, feature_index, mask, lookups, num_lookups, room_lookups);
2010-05-20 16:40:12 +02:00
2010-05-21 18:31:45 +02:00
if (feature->start == 0 && feature->end == (unsigned int) -1)
global_mask |= value;
else
2010-05-21 18:31:45 +02:00
buffer->or_masks (mask, feature->start, feature->end);
2010-05-20 14:40:18 +02:00
}
2010-05-21 18:31:45 +02:00
if (global_mask)
buffer->or_masks (global_mask, 0, (unsigned int) -1);
qsort (lookups, *num_lookups, sizeof (lookups[0]), cmp_lookups);
if (*num_lookups)
{
for (i = 1, j = 0; i < *num_lookups; i++)
2010-05-20 16:14:44 +02:00
if (lookups[i].index != lookups[j].index)
lookups[++j] = lookups[i];
2010-05-20 16:14:44 +02:00
else
lookups[j].mask |= lookups[i].mask;
j++;
*num_lookups = j;
}
}
static hb_bool_t
hb_ot_substitute_complex (hb_font_t *font HB_UNUSED,
hb_face_t *face,
hb_buffer_t *buffer,
hb_feature_t *features,
2010-05-21 18:53:10 +02:00
unsigned int num_features,
hb_direction_t original_direction)
{
2010-05-20 16:14:44 +02:00
lookup_map lookups[1000];
unsigned int num_lookups = ARRAY_LENGTH (lookups);
unsigned int i;
if (!hb_ot_layout_has_substitution (face))
return FALSE;
2010-04-23 20:44:55 +02:00
setup_lookups (face, buffer, features, num_features,
HB_OT_TAG_GSUB,
2010-05-21 18:53:10 +02:00
lookups, &num_lookups,
original_direction);
for (i = 0; i < num_lookups; i++)
2010-05-20 16:14:44 +02:00
hb_ot_layout_substitute_lookup (face, buffer, lookups[i].index, lookups[i].mask);
return TRUE;
}
static hb_bool_t
hb_ot_position_complex (hb_font_t *font,
hb_face_t *face,
hb_buffer_t *buffer,
hb_feature_t *features,
2010-05-21 18:53:10 +02:00
unsigned int num_features,
hb_direction_t original_direction)
{
2010-05-20 16:14:44 +02:00
lookup_map lookups[1000];
unsigned int num_lookups = ARRAY_LENGTH (lookups);
unsigned int i;
if (!hb_ot_layout_has_positioning (face))
return FALSE;
2010-04-23 20:44:55 +02:00
setup_lookups (face, buffer, features, num_features,
HB_OT_TAG_GPOS,
2010-05-21 18:53:10 +02:00
lookups, &num_lookups,
original_direction);
for (i = 0; i < num_lookups; i++)
2010-05-20 16:14:44 +02:00
hb_ot_layout_position_lookup (font, face, buffer, lookups[i].index, lookups[i].mask);
hb_ot_layout_position_finish (font, face, buffer);
return TRUE;
}
/* 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;
}
static hb_direction_t
hb_ensure_native_direction (hb_buffer_t *buffer)
{
hb_direction_t original_direction = buffer->direction;
/* TODO vertical */
if (HB_DIRECTION_IS_HORIZONTAL (original_direction) &&
original_direction != _hb_script_get_horizontal_direction (buffer->script))
{
hb_buffer_reverse_clusters (buffer);
buffer->direction = HB_DIRECTION_REVERSE (buffer->direction);
}
return original_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->direction))
return;
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++) {
2010-05-21 18:58:20 +02:00
hb_codepoint_t codepoint = get_mirroring (buffer->info[i].codepoint);
if (likely (codepoint == buffer->info[i].codepoint))
buffer->info[i].mask |= MASK_RTLM;
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;
unsigned int count = buffer->len - 1;
for (unsigned int i = 0; i < count; i++) {
if (unlikely (is_variation_selector (buffer->info[i + 1].codepoint))) {
buffer->info[i].codepoint = hb_font_get_glyph (font, face, buffer->info[i].codepoint, buffer->info[i + 1].codepoint);
i++;
} else {
buffer->info[i].codepoint = hb_font_get_glyph (font, face, buffer->info[i].codepoint, 0);
}
}
buffer->info[count].codepoint = hb_font_get_glyph (font, face, buffer->info[count].codepoint, 0);
}
static void
hb_substitute_default (hb_font_t *font,
hb_face_t *face,
hb_buffer_t *buffer,
hb_feature_t *features HB_UNUSED,
unsigned int num_features HB_UNUSED)
{
hb_map_glyphs (font, face, buffer);
}
static void
2010-05-21 15:37:47 +02:00
hb_substitute_complex_fallback (hb_font_t *font HB_UNUSED,
hb_face_t *face HB_UNUSED,
hb_buffer_t *buffer HB_UNUSED,
hb_feature_t *features HB_UNUSED,
unsigned int num_features HB_UNUSED)
{
/* TODO Arabic */
}
/* Position */
static void
hb_position_default (hb_font_t *font,
hb_face_t *face,
hb_buffer_t *buffer,
hb_feature_t *features HB_UNUSED,
unsigned int num_features HB_UNUSED)
{
hb_buffer_clear_positions (buffer);
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++) {
hb_glyph_metrics_t metrics;
hb_font_get_glyph_metrics (font, face, buffer->info[i].codepoint, &metrics);
buffer->pos[i].x_advance = metrics.x_advance;
buffer->pos[i].y_advance = metrics.y_advance;
}
}
static void
2010-05-21 15:37:47 +02:00
hb_position_complex_fallback (hb_font_t *font HB_UNUSED,
hb_face_t *face HB_UNUSED,
hb_buffer_t *buffer HB_UNUSED,
hb_feature_t *features HB_UNUSED,
unsigned int num_features HB_UNUSED)
{
/* TODO Mark pos */
}
static void
hb_truetype_kern (hb_font_t *font,
hb_face_t *face,
hb_buffer_t *buffer,
hb_feature_t *features HB_UNUSED,
unsigned int num_features HB_UNUSED)
{
/* TODO Check for kern=0 */
unsigned int count = buffer->len;
for (unsigned int i = 1; i < count; i++) {
hb_position_t kern, kern1, kern2;
kern = hb_font_get_kerning (font, face, buffer->info[i - 1].codepoint, buffer->info[i].codepoint);
kern1 = kern >> 1;
kern2 = kern - kern1;
buffer->pos[i - 1].x_advance += kern1;
buffer->pos[i].x_advance += kern2;
buffer->pos[i].x_offset += kern2;
}
}
static void
2010-05-21 15:37:47 +02:00
hb_position_complex_fallback_visual (hb_font_t *font,
hb_face_t *face,
hb_buffer_t *buffer,
hb_feature_t *features,
unsigned int num_features)
{
hb_truetype_kern (font, face, buffer, features, num_features);
}
/* Do it! */
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_direction_t original_direction;
hb_bool_t substitute_fallback, position_fallback;
hb_form_clusters (buffer);
2010-05-21 18:58:20 +02:00
/* SUBSTITUTE */
buffer->clear_masks ();
2010-05-21 19:24:34 +02:00
/* Mirroring needs to see the original direction */
hb_mirror_chars (buffer);
original_direction = hb_ensure_native_direction (buffer);
2010-05-21 19:24:34 +02:00
hb_substitute_default (font, face, buffer, features, num_features);
2010-05-21 18:53:10 +02:00
substitute_fallback = !hb_ot_substitute_complex (font, face, buffer, features, num_features, original_direction);
if (substitute_fallback)
2010-05-21 15:37:47 +02:00
hb_substitute_complex_fallback (font, face, buffer, features, num_features);
2010-05-21 18:58:20 +02:00
/* POSITION */
buffer->clear_masks ();
hb_position_default (font, face, buffer, features, num_features);
2010-05-21 18:53:10 +02:00
position_fallback = !hb_ot_position_complex (font, face, buffer, features, num_features, original_direction);
if (position_fallback)
2010-05-21 15:37:47 +02:00
hb_position_complex_fallback (font, face, buffer, features, num_features);
if (HB_DIRECTION_IS_BACKWARD (buffer->direction))
hb_buffer_reverse (buffer);
if (position_fallback)
2010-05-21 15:37:47 +02:00
hb_position_complex_fallback_visual (font, face, buffer, features, num_features);
buffer->direction = original_direction;
}