harfbuzz/src/hb-ot-shape.cc

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/*
* Copyright (C) 2009 Red Hat, 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
*/
#include "hb-ot-shape.h"
#include "hb-buffer-private.hh"
#include "hb-ot-layout.h"
hb_tag_t default_features[] = {
/* GSUB */
HB_TAG('c','c','m','p'),
HB_TAG('l','o','c','l'),
HB_TAG('l','i','g','a'),
HB_TAG('c','l','i','g'),
/* GPOS */
HB_TAG('k','e','r','n'),
HB_TAG('m','a','r','k'),
HB_TAG('m','k','m','k'),
};
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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,
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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;
}
static void
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setup_lookups (hb_face_t *face,
hb_buffer_t *buffer,
hb_feature_t *features,
unsigned int num_features,
hb_tag_t table_tag,
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lookup_map *lookups,
unsigned int *num_lookups)
{
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))
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add_feature (face, table_tag, feature_index, 1, lookups, num_lookups, room_lookups);
for (i = 0; i < ARRAY_LENGTH (default_features); i++)
{
if (hb_ot_layout_language_find_feature (face, table_tag, script_index, language_index,
default_features[i],
&feature_index))
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add_feature (face, table_tag, feature_index, 1, lookups, num_lookups, room_lookups);
}
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/* Clear buffer masks. */
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++)
buffer->info[i].mask = 1;
unsigned int last_bit_used = 1;
unsigned int global_values = 0;
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for (i = 0; i < num_features; i++)
{
if (!hb_ot_layout_language_find_feature (face, table_tag, script_index, language_index,
features[i].tag,
&feature_index))
continue;
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unsigned int bits_needed = _hb_bit_storage (features[i].value);
if (!bits_needed)
continue;
unsigned int mask = (1 << (last_bit_used + bits_needed)) - (1 << last_bit_used);
unsigned int value = features[i].value << last_bit_used;
last_bit_used += bits_needed;
add_feature (face, table_tag, feature_index, mask, lookups, num_lookups, room_lookups);
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if (features[i].start == 0 && features[i].end == (unsigned int)-1)
global_values |= value;
else
{
unsigned int start = features[i].start, end = features[i].end;
unsigned int a = 0, b = buffer->len;
while (a < b)
{
unsigned int h = a + ((b - a) / 2);
if (buffer->info[h].cluster < start)
a = h + 1;
else
b = h;
}
unsigned int count = buffer->len;
for (unsigned int j = a; j < count && buffer->info[j].cluster < end; j++)
buffer->info[j].mask |= value;
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}
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}
if (global_values)
{
unsigned int count = buffer->len;
for (unsigned int j = 0; j < count; j++)
buffer->info[j].mask |= global_values;
}
qsort (lookups, *num_lookups, sizeof (lookups[0]), cmp_lookups);
if (*num_lookups)
{
for (i = 1, j = 0; 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;
}
}
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,
unsigned int num_features)
{
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lookup_map lookups[1000];
unsigned int num_lookups = ARRAY_LENGTH (lookups);
unsigned int i;
if (!hb_ot_layout_has_substitution (face))
return FALSE;
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setup_lookups (face, buffer, features, num_features,
HB_OT_TAG_GSUB,
lookups, &num_lookups);
for (i = 0; i < num_lookups; i++)
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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,
unsigned int num_features)
{
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lookup_map lookups[1000];
unsigned int num_lookups = ARRAY_LENGTH (lookups);
unsigned int i;
if (!hb_ot_layout_has_positioning (face))
return FALSE;
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setup_lookups (face, buffer, features, num_features,
HB_OT_TAG_GPOS,
lookups, &num_lookups);
for (i = 0; i < num_lookups; i++)
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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->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->get_mirroring;
if (HB_DIRECTION_IS_FORWARD (buffer->direction))
return;
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++) {
buffer->info[i].codepoint = get_mirroring (buffer->info[i].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_mirror_chars (buffer);
hb_map_glyphs (font, face, buffer);
}
static void
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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
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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
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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);
hb_substitute_default (font, face, buffer, features, num_features);
/* We do this after substitute_default because mirroring needs to
* see the original direction. */
original_direction = hb_ensure_native_direction (buffer);
substitute_fallback = !hb_ot_substitute_complex (font, face, buffer, features, num_features);
if (substitute_fallback)
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hb_substitute_complex_fallback (font, face, buffer, features, num_features);
hb_position_default (font, face, buffer, features, num_features);
position_fallback = !hb_ot_position_complex (font, face, buffer, features, num_features);
if (position_fallback)
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hb_position_complex_fallback (font, face, buffer, features, num_features);
if (HB_DIRECTION_IS_BACKWARD (buffer->direction))
hb_buffer_reverse (buffer);
if (position_fallback)
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hb_position_complex_fallback_visual (font, face, buffer, features, num_features);
buffer->direction = original_direction;
}