1573 lines
51 KiB
C++
1573 lines
51 KiB
C++
/*
|
||
* 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"
|
||
|
||
#ifndef HB_NO_OT_SHAPE
|
||
|
||
#include "hb-ot-shape-complex-indic.hh"
|
||
#include "hb-ot-shape-complex-indic-machine.hh"
|
||
#include "hb-ot-shape-complex-vowel-constraints.hh"
|
||
#include "hb-ot-layout.hh"
|
||
|
||
|
||
/*
|
||
* Indic shaper.
|
||
*/
|
||
|
||
|
||
/*
|
||
* Indic configurations. Note that we do not want to keep every single script-specific
|
||
* behavior in these tables necessarily. This should mainly be used for per-script
|
||
* properties that are cheaper keeping here, than in the code. Ie. if, say, one and
|
||
* only one script has an exception, that one script can be if'ed directly in the code,
|
||
* instead of adding a new flag in these structs.
|
||
*/
|
||
|
||
enum base_position_t {
|
||
BASE_POS_LAST_SINHALA,
|
||
BASE_POS_LAST
|
||
};
|
||
enum reph_position_t {
|
||
REPH_POS_AFTER_MAIN = POS_AFTER_MAIN,
|
||
REPH_POS_BEFORE_SUB = POS_BEFORE_SUB,
|
||
REPH_POS_AFTER_SUB = POS_AFTER_SUB,
|
||
REPH_POS_BEFORE_POST = POS_BEFORE_POST,
|
||
REPH_POS_AFTER_POST = POS_AFTER_POST
|
||
};
|
||
enum reph_mode_t {
|
||
REPH_MODE_IMPLICIT, /* Reph formed out of initial Ra,H sequence. */
|
||
REPH_MODE_EXPLICIT, /* Reph formed out of initial Ra,H,ZWJ sequence. */
|
||
REPH_MODE_LOG_REPHA /* Encoded Repha character, needs reordering. */
|
||
};
|
||
enum blwf_mode_t {
|
||
BLWF_MODE_PRE_AND_POST, /* Below-forms feature applied to pre-base and post-base. */
|
||
BLWF_MODE_POST_ONLY /* Below-forms feature applied to post-base only. */
|
||
};
|
||
struct indic_config_t
|
||
{
|
||
hb_script_t script;
|
||
bool has_old_spec;
|
||
hb_codepoint_t virama;
|
||
base_position_t base_pos;
|
||
reph_position_t reph_pos;
|
||
reph_mode_t reph_mode;
|
||
blwf_mode_t blwf_mode;
|
||
};
|
||
|
||
static const indic_config_t indic_configs[] =
|
||
{
|
||
/* Default. Should be first. */
|
||
{HB_SCRIPT_INVALID, false, 0,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
|
||
{HB_SCRIPT_DEVANAGARI,true, 0x094Du,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
|
||
{HB_SCRIPT_BENGALI, true, 0x09CDu,BASE_POS_LAST, REPH_POS_AFTER_SUB, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
|
||
{HB_SCRIPT_GURMUKHI, true, 0x0A4Du,BASE_POS_LAST, REPH_POS_BEFORE_SUB, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
|
||
{HB_SCRIPT_GUJARATI, true, 0x0ACDu,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
|
||
{HB_SCRIPT_ORIYA, true, 0x0B4Du,BASE_POS_LAST, REPH_POS_AFTER_MAIN, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
|
||
{HB_SCRIPT_TAMIL, true, 0x0BCDu,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
|
||
{HB_SCRIPT_TELUGU, true, 0x0C4Du,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_EXPLICIT, BLWF_MODE_POST_ONLY},
|
||
{HB_SCRIPT_KANNADA, true, 0x0CCDu,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT, BLWF_MODE_POST_ONLY},
|
||
{HB_SCRIPT_MALAYALAM, true, 0x0D4Du,BASE_POS_LAST, REPH_POS_AFTER_MAIN, REPH_MODE_LOG_REPHA,BLWF_MODE_PRE_AND_POST},
|
||
{HB_SCRIPT_SINHALA, false,0x0DCAu,BASE_POS_LAST_SINHALA,
|
||
REPH_POS_AFTER_POST, REPH_MODE_EXPLICIT, BLWF_MODE_PRE_AND_POST},
|
||
};
|
||
|
||
|
||
|
||
/*
|
||
* Indic shaper.
|
||
*/
|
||
|
||
static const hb_ot_map_feature_t
|
||
indic_features[] =
|
||
{
|
||
/*
|
||
* Basic features.
|
||
* These features are applied in order, one at a time, after initial_reordering,
|
||
* constrained to the syllable.
|
||
*/
|
||
{HB_TAG('n','u','k','t'), F_GLOBAL_MANUAL_JOINERS},
|
||
{HB_TAG('a','k','h','n'), F_GLOBAL_MANUAL_JOINERS},
|
||
{HB_TAG('r','p','h','f'), F_MANUAL_JOINERS},
|
||
{HB_TAG('r','k','r','f'), F_GLOBAL_MANUAL_JOINERS},
|
||
{HB_TAG('p','r','e','f'), F_MANUAL_JOINERS},
|
||
{HB_TAG('b','l','w','f'), F_MANUAL_JOINERS},
|
||
{HB_TAG('a','b','v','f'), F_MANUAL_JOINERS},
|
||
{HB_TAG('h','a','l','f'), F_MANUAL_JOINERS},
|
||
{HB_TAG('p','s','t','f'), F_MANUAL_JOINERS},
|
||
{HB_TAG('v','a','t','u'), F_GLOBAL_MANUAL_JOINERS},
|
||
{HB_TAG('c','j','c','t'), F_GLOBAL_MANUAL_JOINERS},
|
||
/*
|
||
* Other features.
|
||
* These features are applied all at once, after final_reordering, constrained
|
||
* to the syllable.
|
||
* Default Bengali font in Windows for example has intermixed
|
||
* lookups for init,pres,abvs,blws features.
|
||
*/
|
||
{HB_TAG('i','n','i','t'), F_MANUAL_JOINERS},
|
||
{HB_TAG('p','r','e','s'), F_GLOBAL_MANUAL_JOINERS},
|
||
{HB_TAG('a','b','v','s'), F_GLOBAL_MANUAL_JOINERS},
|
||
{HB_TAG('b','l','w','s'), F_GLOBAL_MANUAL_JOINERS},
|
||
{HB_TAG('p','s','t','s'), F_GLOBAL_MANUAL_JOINERS},
|
||
{HB_TAG('h','a','l','n'), F_GLOBAL_MANUAL_JOINERS},
|
||
};
|
||
|
||
/*
|
||
* Must be in the same order as the indic_features array.
|
||
*/
|
||
enum {
|
||
_INDIC_NUKT,
|
||
_INDIC_AKHN,
|
||
INDIC_RPHF,
|
||
_INDIC_RKRF,
|
||
INDIC_PREF,
|
||
INDIC_BLWF,
|
||
INDIC_ABVF,
|
||
INDIC_HALF,
|
||
INDIC_PSTF,
|
||
_INDIC_VATU,
|
||
_INDIC_CJCT,
|
||
|
||
INDIC_INIT,
|
||
_INDIC_PRES,
|
||
_INDIC_ABVS,
|
||
_INDIC_BLWS,
|
||
_INDIC_PSTS,
|
||
_INDIC_HALN,
|
||
|
||
INDIC_NUM_FEATURES,
|
||
INDIC_BASIC_FEATURES = INDIC_INIT, /* Don't forget to update this! */
|
||
};
|
||
|
||
static void
|
||
setup_syllables_indic (const hb_ot_shape_plan_t *plan,
|
||
hb_font_t *font,
|
||
hb_buffer_t *buffer);
|
||
static void
|
||
initial_reordering_indic (const hb_ot_shape_plan_t *plan,
|
||
hb_font_t *font,
|
||
hb_buffer_t *buffer);
|
||
static void
|
||
final_reordering_indic (const hb_ot_shape_plan_t *plan,
|
||
hb_font_t *font,
|
||
hb_buffer_t *buffer);
|
||
|
||
static void
|
||
collect_features_indic (hb_ot_shape_planner_t *plan)
|
||
{
|
||
hb_ot_map_builder_t *map = &plan->map;
|
||
|
||
/* Do this before any lookups have been applied. */
|
||
map->add_gsub_pause (setup_syllables_indic);
|
||
|
||
map->enable_feature (HB_TAG('l','o','c','l'));
|
||
/* The Indic specs do not require ccmp, but we apply it here since if
|
||
* there is a use of it, it's typically at the beginning. */
|
||
map->enable_feature (HB_TAG('c','c','m','p'));
|
||
|
||
|
||
unsigned int i = 0;
|
||
map->add_gsub_pause (initial_reordering_indic);
|
||
|
||
for (; i < INDIC_BASIC_FEATURES; i++) {
|
||
map->add_feature (indic_features[i]);
|
||
map->add_gsub_pause (nullptr);
|
||
}
|
||
|
||
map->add_gsub_pause (final_reordering_indic);
|
||
|
||
for (; i < INDIC_NUM_FEATURES; i++)
|
||
map->add_feature (indic_features[i]);
|
||
|
||
map->add_gsub_pause (_hb_clear_syllables);
|
||
}
|
||
|
||
static void
|
||
override_features_indic (hb_ot_shape_planner_t *plan)
|
||
{
|
||
plan->map.disable_feature (HB_TAG('l','i','g','a'));
|
||
}
|
||
|
||
|
||
struct indic_shape_plan_t
|
||
{
|
||
bool load_virama_glyph (hb_font_t *font, hb_codepoint_t *pglyph) const
|
||
{
|
||
hb_codepoint_t glyph = virama_glyph.get_relaxed ();
|
||
if (unlikely (glyph == (hb_codepoint_t) -1))
|
||
{
|
||
if (!config->virama || !font->get_nominal_glyph (config->virama, &glyph))
|
||
glyph = 0;
|
||
/* Technically speaking, the spec says we should apply 'locl' to virama too.
|
||
* Maybe one day... */
|
||
|
||
/* Our get_nominal_glyph() function needs a font, so we can't get the virama glyph
|
||
* during shape planning... Instead, overwrite it here. */
|
||
virama_glyph.set_relaxed ((int) glyph);
|
||
}
|
||
|
||
*pglyph = glyph;
|
||
return glyph != 0;
|
||
}
|
||
|
||
const indic_config_t *config;
|
||
|
||
bool is_old_spec;
|
||
#ifndef HB_NO_UNISCRIBE_BUG_COMPATIBLE
|
||
bool uniscribe_bug_compatible;
|
||
#else
|
||
static constexpr bool uniscribe_bug_compatible = false;
|
||
#endif
|
||
mutable hb_atomic_int_t virama_glyph;
|
||
|
||
hb_indic_would_substitute_feature_t rphf;
|
||
hb_indic_would_substitute_feature_t pref;
|
||
hb_indic_would_substitute_feature_t blwf;
|
||
hb_indic_would_substitute_feature_t pstf;
|
||
hb_indic_would_substitute_feature_t vatu;
|
||
|
||
hb_mask_t mask_array[INDIC_NUM_FEATURES];
|
||
};
|
||
|
||
static void *
|
||
data_create_indic (const hb_ot_shape_plan_t *plan)
|
||
{
|
||
indic_shape_plan_t *indic_plan = (indic_shape_plan_t *) hb_calloc (1, sizeof (indic_shape_plan_t));
|
||
if (unlikely (!indic_plan))
|
||
return nullptr;
|
||
|
||
indic_plan->config = &indic_configs[0];
|
||
for (unsigned int i = 1; i < ARRAY_LENGTH (indic_configs); i++)
|
||
if (plan->props.script == indic_configs[i].script) {
|
||
indic_plan->config = &indic_configs[i];
|
||
break;
|
||
}
|
||
|
||
indic_plan->is_old_spec = indic_plan->config->has_old_spec && ((plan->map.chosen_script[0] & 0x000000FFu) != '2');
|
||
#ifndef HB_NO_UNISCRIBE_BUG_COMPATIBLE
|
||
indic_plan->uniscribe_bug_compatible = hb_options ().uniscribe_bug_compatible;
|
||
#endif
|
||
indic_plan->virama_glyph.set_relaxed (-1);
|
||
|
||
/* Use zero-context would_substitute() matching for new-spec of the main
|
||
* Indic scripts, and scripts with one spec only, but not for old-specs.
|
||
* The new-spec for all dual-spec scripts says zero-context matching happens.
|
||
*
|
||
* However, testing with Malayalam shows that old and new spec both allow
|
||
* context. Testing with Bengali new-spec however shows that it doesn't.
|
||
* So, the heuristic here is the way it is. It should *only* be changed,
|
||
* as we discover more cases of what Windows does. DON'T TOUCH OTHERWISE.
|
||
*/
|
||
bool zero_context = !indic_plan->is_old_spec && plan->props.script != HB_SCRIPT_MALAYALAM;
|
||
indic_plan->rphf.init (&plan->map, HB_TAG('r','p','h','f'), zero_context);
|
||
indic_plan->pref.init (&plan->map, HB_TAG('p','r','e','f'), zero_context);
|
||
indic_plan->blwf.init (&plan->map, HB_TAG('b','l','w','f'), zero_context);
|
||
indic_plan->pstf.init (&plan->map, HB_TAG('p','s','t','f'), zero_context);
|
||
indic_plan->vatu.init (&plan->map, HB_TAG('v','a','t','u'), zero_context);
|
||
|
||
for (unsigned int i = 0; i < ARRAY_LENGTH (indic_plan->mask_array); i++)
|
||
indic_plan->mask_array[i] = (indic_features[i].flags & F_GLOBAL) ?
|
||
0 : plan->map.get_1_mask (indic_features[i].tag);
|
||
|
||
return indic_plan;
|
||
}
|
||
|
||
static void
|
||
data_destroy_indic (void *data)
|
||
{
|
||
hb_free (data);
|
||
}
|
||
|
||
static indic_position_t
|
||
consonant_position_from_face (const indic_shape_plan_t *indic_plan,
|
||
const hb_codepoint_t consonant,
|
||
const hb_codepoint_t virama,
|
||
hb_face_t *face)
|
||
{
|
||
/* For old-spec, the order of glyphs is Consonant,Virama,
|
||
* whereas for new-spec, it's Virama,Consonant. However,
|
||
* some broken fonts (like Free Sans) simply copied lookups
|
||
* from old-spec to new-spec without modification.
|
||
* And oddly enough, Uniscribe seems to respect those lookups.
|
||
* Eg. in the sequence U+0924,U+094D,U+0930, Uniscribe finds
|
||
* base at 0. The font however, only has lookups matching
|
||
* 930,94D in 'blwf', not the expected 94D,930 (with new-spec
|
||
* table). As such, we simply match both sequences. Seems
|
||
* to work.
|
||
*
|
||
* Vatu is done as well, for:
|
||
* https://github.com/harfbuzz/harfbuzz/issues/1587
|
||
*/
|
||
hb_codepoint_t glyphs[3] = {virama, consonant, virama};
|
||
if (indic_plan->blwf.would_substitute (glyphs , 2, face) ||
|
||
indic_plan->blwf.would_substitute (glyphs+1, 2, face) ||
|
||
indic_plan->vatu.would_substitute (glyphs , 2, face) ||
|
||
indic_plan->vatu.would_substitute (glyphs+1, 2, face))
|
||
return POS_BELOW_C;
|
||
if (indic_plan->pstf.would_substitute (glyphs , 2, face) ||
|
||
indic_plan->pstf.would_substitute (glyphs+1, 2, face))
|
||
return POS_POST_C;
|
||
if (indic_plan->pref.would_substitute (glyphs , 2, face) ||
|
||
indic_plan->pref.would_substitute (glyphs+1, 2, face))
|
||
return POS_POST_C;
|
||
return POS_BASE_C;
|
||
}
|
||
|
||
static void
|
||
setup_masks_indic (const hb_ot_shape_plan_t *plan HB_UNUSED,
|
||
hb_buffer_t *buffer,
|
||
hb_font_t *font HB_UNUSED)
|
||
{
|
||
HB_BUFFER_ALLOCATE_VAR (buffer, indic_category);
|
||
HB_BUFFER_ALLOCATE_VAR (buffer, indic_position);
|
||
|
||
/* We cannot setup masks here. We save information about characters
|
||
* and setup masks later on in a pause-callback. */
|
||
|
||
unsigned int count = buffer->len;
|
||
hb_glyph_info_t *info = buffer->info;
|
||
for (unsigned int i = 0; i < count; i++)
|
||
set_indic_properties (info[i]);
|
||
}
|
||
|
||
static void
|
||
setup_syllables_indic (const hb_ot_shape_plan_t *plan HB_UNUSED,
|
||
hb_font_t *font HB_UNUSED,
|
||
hb_buffer_t *buffer)
|
||
{
|
||
find_syllables_indic (buffer);
|
||
foreach_syllable (buffer, start, end)
|
||
buffer->unsafe_to_break (start, end);
|
||
}
|
||
|
||
static int
|
||
compare_indic_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb)
|
||
{
|
||
int a = pa->indic_position();
|
||
int b = pb->indic_position();
|
||
|
||
return a < b ? -1 : a == b ? 0 : +1;
|
||
}
|
||
|
||
|
||
|
||
static void
|
||
update_consonant_positions_indic (const hb_ot_shape_plan_t *plan,
|
||
hb_font_t *font,
|
||
hb_buffer_t *buffer)
|
||
{
|
||
const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
|
||
|
||
if (indic_plan->config->base_pos != BASE_POS_LAST)
|
||
return;
|
||
|
||
hb_codepoint_t virama;
|
||
if (indic_plan->load_virama_glyph (font, &virama))
|
||
{
|
||
hb_face_t *face = font->face;
|
||
unsigned int count = buffer->len;
|
||
hb_glyph_info_t *info = buffer->info;
|
||
for (unsigned int i = 0; i < count; i++)
|
||
if (info[i].indic_position() == POS_BASE_C)
|
||
{
|
||
hb_codepoint_t consonant = info[i].codepoint;
|
||
info[i].indic_position() = consonant_position_from_face (indic_plan, consonant, virama, face);
|
||
}
|
||
}
|
||
}
|
||
|
||
|
||
/* Rules from:
|
||
* https://docs.microsqoft.com/en-us/typography/script-development/devanagari */
|
||
|
||
static void
|
||
initial_reordering_consonant_syllable (const hb_ot_shape_plan_t *plan,
|
||
hb_face_t *face,
|
||
hb_buffer_t *buffer,
|
||
unsigned int start, unsigned int end)
|
||
{
|
||
const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
|
||
hb_glyph_info_t *info = buffer->info;
|
||
|
||
/* https://github.com/harfbuzz/harfbuzz/issues/435#issuecomment-335560167
|
||
* // For compatibility with legacy usage in Kannada,
|
||
* // Ra+h+ZWJ must behave like Ra+ZWJ+h...
|
||
*/
|
||
if (buffer->props.script == HB_SCRIPT_KANNADA &&
|
||
start + 3 <= end &&
|
||
is_one_of (info[start ], FLAG (OT_Ra)) &&
|
||
is_one_of (info[start+1], FLAG (OT_H)) &&
|
||
is_one_of (info[start+2], FLAG (OT_ZWJ)))
|
||
{
|
||
buffer->merge_clusters (start+1, start+3);
|
||
hb_glyph_info_t tmp = info[start+1];
|
||
info[start+1] = info[start+2];
|
||
info[start+2] = tmp;
|
||
}
|
||
|
||
/* 1. Find base consonant:
|
||
*
|
||
* The shaping engine finds the base consonant of the syllable, using the
|
||
* following algorithm: starting from the end of the syllable, move backwards
|
||
* until a consonant is found that does not have a below-base or post-base
|
||
* form (post-base forms have to follow below-base forms), or that is not a
|
||
* pre-base-reordering Ra, or arrive at the first consonant. The consonant
|
||
* stopped at will be the base.
|
||
*
|
||
* o If the syllable starts with Ra + Halant (in a script that has Reph)
|
||
* and has more than one consonant, Ra is excluded from candidates for
|
||
* base consonants.
|
||
*/
|
||
|
||
unsigned int base = end;
|
||
bool has_reph = false;
|
||
|
||
{
|
||
/* -> If the syllable starts with Ra + Halant (in a script that has Reph)
|
||
* and has more than one consonant, Ra is excluded from candidates for
|
||
* base consonants. */
|
||
unsigned int limit = start;
|
||
if (indic_plan->mask_array[INDIC_RPHF] &&
|
||
start + 3 <= end &&
|
||
(
|
||
(indic_plan->config->reph_mode == REPH_MODE_IMPLICIT && !is_joiner (info[start + 2])) ||
|
||
(indic_plan->config->reph_mode == REPH_MODE_EXPLICIT && info[start + 2].indic_category() == OT_ZWJ)
|
||
))
|
||
{
|
||
/* See if it matches the 'rphf' feature. */
|
||
hb_codepoint_t glyphs[3] = {info[start].codepoint,
|
||
info[start + 1].codepoint,
|
||
indic_plan->config->reph_mode == REPH_MODE_EXPLICIT ?
|
||
info[start + 2].codepoint : 0};
|
||
if (indic_plan->rphf.would_substitute (glyphs, 2, face) ||
|
||
(indic_plan->config->reph_mode == REPH_MODE_EXPLICIT &&
|
||
indic_plan->rphf.would_substitute (glyphs, 3, face)))
|
||
{
|
||
limit += 2;
|
||
while (limit < end && is_joiner (info[limit]))
|
||
limit++;
|
||
base = start;
|
||
has_reph = true;
|
||
}
|
||
} else if (indic_plan->config->reph_mode == REPH_MODE_LOG_REPHA && info[start].indic_category() == OT_Repha)
|
||
{
|
||
limit += 1;
|
||
while (limit < end && is_joiner (info[limit]))
|
||
limit++;
|
||
base = start;
|
||
has_reph = true;
|
||
}
|
||
|
||
switch (indic_plan->config->base_pos)
|
||
{
|
||
case BASE_POS_LAST:
|
||
{
|
||
/* -> starting from the end of the syllable, move backwards */
|
||
unsigned int i = end;
|
||
bool seen_below = false;
|
||
do {
|
||
i--;
|
||
/* -> until a consonant is found */
|
||
if (is_consonant (info[i]))
|
||
{
|
||
/* -> that does not have a below-base or post-base form
|
||
* (post-base forms have to follow below-base forms), */
|
||
if (info[i].indic_position() != POS_BELOW_C &&
|
||
(info[i].indic_position() != POS_POST_C || seen_below))
|
||
{
|
||
base = i;
|
||
break;
|
||
}
|
||
if (info[i].indic_position() == POS_BELOW_C)
|
||
seen_below = true;
|
||
|
||
/* -> or that is not a pre-base-reordering Ra,
|
||
*
|
||
* IMPLEMENTATION NOTES:
|
||
*
|
||
* Our pre-base-reordering Ra's are marked POS_POST_C, so will be skipped
|
||
* by the logic above already.
|
||
*/
|
||
|
||
/* -> or arrive at the first consonant. The consonant stopped at will
|
||
* be the base. */
|
||
base = i;
|
||
}
|
||
else
|
||
{
|
||
/* A ZWJ after a Halant stops the base search, and requests an explicit
|
||
* half form.
|
||
* A ZWJ before a Halant, requests a subjoined form instead, and hence
|
||
* search continues. This is particularly important for Bengali
|
||
* sequence Ra,H,Ya that should form Ya-Phalaa by subjoining Ya. */
|
||
if (start < i &&
|
||
info[i].indic_category() == OT_ZWJ &&
|
||
info[i - 1].indic_category() == OT_H)
|
||
break;
|
||
}
|
||
} while (i > limit);
|
||
}
|
||
break;
|
||
|
||
case BASE_POS_LAST_SINHALA:
|
||
{
|
||
/* Sinhala base positioning is slightly different from main Indic, in that:
|
||
* 1. Its ZWJ behavior is different,
|
||
* 2. We don't need to look into the font for consonant positions.
|
||
*/
|
||
|
||
if (!has_reph)
|
||
base = limit;
|
||
|
||
/* Find the last base consonant that is not blocked by ZWJ. If there is
|
||
* a ZWJ right before a base consonant, that would request a subjoined form. */
|
||
for (unsigned int i = limit; i < end; i++)
|
||
if (is_consonant (info[i]))
|
||
{
|
||
if (limit < i && info[i - 1].indic_category() == OT_ZWJ)
|
||
break;
|
||
else
|
||
base = i;
|
||
}
|
||
|
||
/* Mark all subsequent consonants as below. */
|
||
for (unsigned int i = base + 1; i < end; i++)
|
||
if (is_consonant (info[i]))
|
||
info[i].indic_position() = POS_BELOW_C;
|
||
}
|
||
break;
|
||
}
|
||
|
||
/* -> If the syllable starts with Ra + Halant (in a script that has Reph)
|
||
* and has more than one consonant, Ra is excluded from candidates for
|
||
* base consonants.
|
||
*
|
||
* Only do this for unforced Reph. (ie. not for Ra,H,ZWJ. */
|
||
if (has_reph && base == start && limit - base <= 2) {
|
||
/* Have no other consonant, so Reph is not formed and Ra becomes base. */
|
||
has_reph = false;
|
||
}
|
||
}
|
||
|
||
|
||
/* 2. Decompose and reorder Matras:
|
||
*
|
||
* Each matra and any syllable modifier sign in the syllable are moved to the
|
||
* appropriate position relative to the consonant(s) in the syllable. The
|
||
* shaping engine decomposes two- or three-part matras into their constituent
|
||
* parts before any repositioning. Matra characters are classified by which
|
||
* consonant in a conjunct they have affinity for and are reordered to the
|
||
* following positions:
|
||
*
|
||
* o Before first half form in the syllable
|
||
* o After subjoined consonants
|
||
* o After post-form consonant
|
||
* o After main consonant (for above marks)
|
||
*
|
||
* IMPLEMENTATION NOTES:
|
||
*
|
||
* The normalize() routine has already decomposed matras for us, so we don't
|
||
* need to worry about that.
|
||
*/
|
||
|
||
|
||
/* 3. Reorder marks to canonical order:
|
||
*
|
||
* Adjacent nukta and halant or nukta and vedic sign are always repositioned
|
||
* if necessary, so that the nukta is first.
|
||
*
|
||
* IMPLEMENTATION NOTES:
|
||
*
|
||
* We don't need to do this: the normalize() routine already did this for us.
|
||
*/
|
||
|
||
|
||
/* Reorder characters */
|
||
|
||
for (unsigned int i = start; i < base; i++)
|
||
info[i].indic_position() = hb_min (POS_PRE_C, (indic_position_t) info[i].indic_position());
|
||
|
||
if (base < end)
|
||
info[base].indic_position() = POS_BASE_C;
|
||
|
||
/* Mark final consonants. A final consonant is one appearing after a matra.
|
||
* Happens in Sinhala. */
|
||
for (unsigned int i = base + 1; i < end; i++)
|
||
if (info[i].indic_category() == OT_M) {
|
||
for (unsigned int j = i + 1; j < end; j++)
|
||
if (is_consonant (info[j])) {
|
||
info[j].indic_position() = POS_FINAL_C;
|
||
break;
|
||
}
|
||
break;
|
||
}
|
||
|
||
/* Handle beginning Ra */
|
||
if (has_reph)
|
||
info[start].indic_position() = POS_RA_TO_BECOME_REPH;
|
||
|
||
/* For old-style Indic script tags, move the first post-base Halant after
|
||
* last consonant.
|
||
*
|
||
* Reports suggest that in some scripts Uniscribe does this only if there
|
||
* is *not* a Halant after last consonant already. We know that is the
|
||
* case for Kannada, while it reorders unconditionally in other scripts,
|
||
* eg. Malayalam, Bengali, and Devanagari. We don't currently know about
|
||
* other scripts, so we block Kannada.
|
||
*
|
||
* Kannada test case:
|
||
* U+0C9A,U+0CCD,U+0C9A,U+0CCD
|
||
* With some versions of Lohit Kannada.
|
||
* https://bugs.freedesktop.org/show_bug.cgi?id=59118
|
||
*
|
||
* Malayalam test case:
|
||
* U+0D38,U+0D4D,U+0D31,U+0D4D,U+0D31,U+0D4D
|
||
* With lohit-ttf-20121122/Lohit-Malayalam.ttf
|
||
*
|
||
* Bengali test case:
|
||
* U+0998,U+09CD,U+09AF,U+09CD
|
||
* With Windows XP vrinda.ttf
|
||
* https://github.com/harfbuzz/harfbuzz/issues/1073
|
||
*
|
||
* Devanagari test case:
|
||
* U+091F,U+094D,U+0930,U+094D
|
||
* With chandas.ttf
|
||
* https://github.com/harfbuzz/harfbuzz/issues/1071
|
||
*/
|
||
if (indic_plan->is_old_spec)
|
||
{
|
||
bool disallow_double_halants = buffer->props.script == HB_SCRIPT_KANNADA;
|
||
for (unsigned int i = base + 1; i < end; i++)
|
||
if (info[i].indic_category() == OT_H)
|
||
{
|
||
unsigned int j;
|
||
for (j = end - 1; j > i; j--)
|
||
if (is_consonant (info[j]) ||
|
||
(disallow_double_halants && info[j].indic_category() == OT_H))
|
||
break;
|
||
if (info[j].indic_category() != OT_H && j > i) {
|
||
/* Move Halant to after last consonant. */
|
||
hb_glyph_info_t t = info[i];
|
||
memmove (&info[i], &info[i + 1], (j - i) * sizeof (info[0]));
|
||
info[j] = t;
|
||
}
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* Attach misc marks to previous char to move with them. */
|
||
{
|
||
indic_position_t last_pos = POS_START;
|
||
for (unsigned int i = start; i < end; i++)
|
||
{
|
||
if ((FLAG_UNSAFE (info[i].indic_category()) & (JOINER_FLAGS | FLAG (OT_N) | FLAG (OT_RS) | MEDIAL_FLAGS | FLAG (OT_H))))
|
||
{
|
||
info[i].indic_position() = last_pos;
|
||
if (unlikely (info[i].indic_category() == OT_H &&
|
||
info[i].indic_position() == POS_PRE_M))
|
||
{
|
||
/*
|
||
* Uniscribe doesn't move the Halant with Left Matra.
|
||
* TEST: U+092B,U+093F,U+094DE
|
||
* We follow. This is important for the Sinhala
|
||
* U+0DDA split matra since it decomposes to U+0DD9,U+0DCA
|
||
* where U+0DD9 is a left matra and U+0DCA is the virama.
|
||
* We don't want to move the virama with the left matra.
|
||
* TEST: U+0D9A,U+0DDA
|
||
*/
|
||
for (unsigned int j = i; j > start; j--)
|
||
if (info[j - 1].indic_position() != POS_PRE_M) {
|
||
info[i].indic_position() = info[j - 1].indic_position();
|
||
break;
|
||
}
|
||
}
|
||
} else if (info[i].indic_position() != POS_SMVD) {
|
||
last_pos = (indic_position_t) info[i].indic_position();
|
||
}
|
||
}
|
||
}
|
||
/* For post-base consonants let them own anything before them
|
||
* since the last consonant or matra. */
|
||
{
|
||
unsigned int last = base;
|
||
for (unsigned int i = base + 1; i < end; i++)
|
||
if (is_consonant (info[i]))
|
||
{
|
||
for (unsigned int j = last + 1; j < i; j++)
|
||
if (info[j].indic_position() < POS_SMVD)
|
||
info[j].indic_position() = info[i].indic_position();
|
||
last = i;
|
||
} else if (info[i].indic_category() == OT_M)
|
||
last = i;
|
||
}
|
||
|
||
|
||
{
|
||
/* Use syllable() for sort accounting temporarily. */
|
||
unsigned int syllable = info[start].syllable();
|
||
for (unsigned int i = start; i < end; i++)
|
||
info[i].syllable() = i - start;
|
||
|
||
/* Sit tight, rock 'n roll! */
|
||
hb_stable_sort (info + start, end - start, compare_indic_order);
|
||
/* Find base again */
|
||
base = end;
|
||
for (unsigned int i = start; i < end; i++)
|
||
if (info[i].indic_position() == POS_BASE_C)
|
||
{
|
||
base = i;
|
||
break;
|
||
}
|
||
/* Things are out-of-control for post base positions, they may shuffle
|
||
* around like crazy. In old-spec mode, we move halants around, so in
|
||
* that case merge all clusters after base. Otherwise, check the sort
|
||
* order and merge as needed.
|
||
* For pre-base stuff, we handle cluster issues in final reordering.
|
||
*
|
||
* We could use buffer->sort() for this, if there was no special
|
||
* reordering of pre-base stuff happening later...
|
||
* We don't want to merge_clusters all of that, which buffer->sort()
|
||
* would. Here's a concrete example:
|
||
*
|
||
* Assume there's a pre-base consonant and explicit Halant before base,
|
||
* followed by a prebase-reordering (left) Matra:
|
||
*
|
||
* C,H,ZWNJ,B,M
|
||
*
|
||
* At this point in reordering we would have:
|
||
*
|
||
* M,C,H,ZWNJ,B
|
||
*
|
||
* whereas in final reordering we will bring the Matra closer to Base:
|
||
*
|
||
* C,H,ZWNJ,M,B
|
||
*
|
||
* That's why we don't want to merge-clusters anything before the Base
|
||
* at this point. But if something moved from after Base to before it,
|
||
* we should merge clusters from base to them. In final-reordering, we
|
||
* only move things around before base, and merge-clusters up to base.
|
||
* These two merge-clusters from the two sides of base will interlock
|
||
* to merge things correctly. See:
|
||
* https://github.com/harfbuzz/harfbuzz/issues/2272
|
||
*/
|
||
if (indic_plan->is_old_spec || end - start > 127)
|
||
buffer->merge_clusters (base, end);
|
||
else
|
||
{
|
||
/* Note! syllable() is a one-byte field. */
|
||
for (unsigned int i = base; i < end; i++)
|
||
if (info[i].syllable() != 255)
|
||
{
|
||
unsigned int min = i;
|
||
unsigned int max = i;
|
||
unsigned int j = start + info[i].syllable();
|
||
while (j != i)
|
||
{
|
||
min = hb_min (min, j);
|
||
max = hb_max (max, j);
|
||
unsigned int next = start + info[j].syllable();
|
||
info[j].syllable() = 255; /* So we don't process j later again. */
|
||
j = next;
|
||
}
|
||
buffer->merge_clusters (hb_max (base, min), max + 1);
|
||
}
|
||
}
|
||
|
||
/* Put syllable back in. */
|
||
for (unsigned int i = start; i < end; i++)
|
||
info[i].syllable() = syllable;
|
||
}
|
||
|
||
/* Setup masks now */
|
||
|
||
{
|
||
hb_mask_t mask;
|
||
|
||
/* Reph */
|
||
for (unsigned int i = start; i < end && info[i].indic_position() == POS_RA_TO_BECOME_REPH; i++)
|
||
info[i].mask |= indic_plan->mask_array[INDIC_RPHF];
|
||
|
||
/* Pre-base */
|
||
mask = indic_plan->mask_array[INDIC_HALF];
|
||
if (!indic_plan->is_old_spec &&
|
||
indic_plan->config->blwf_mode == BLWF_MODE_PRE_AND_POST)
|
||
mask |= indic_plan->mask_array[INDIC_BLWF];
|
||
for (unsigned int i = start; i < base; i++)
|
||
info[i].mask |= mask;
|
||
/* Base */
|
||
mask = 0;
|
||
if (base < end)
|
||
info[base].mask |= mask;
|
||
/* Post-base */
|
||
mask = indic_plan->mask_array[INDIC_BLWF] |
|
||
indic_plan->mask_array[INDIC_ABVF] |
|
||
indic_plan->mask_array[INDIC_PSTF];
|
||
for (unsigned int i = base + 1; i < end; i++)
|
||
info[i].mask |= mask;
|
||
}
|
||
|
||
if (indic_plan->is_old_spec &&
|
||
buffer->props.script == HB_SCRIPT_DEVANAGARI)
|
||
{
|
||
/* Old-spec eye-lash Ra needs special handling. From the
|
||
* spec:
|
||
*
|
||
* "The feature 'below-base form' is applied to consonants
|
||
* having below-base forms and following the base consonant.
|
||
* The exception is vattu, which may appear below half forms
|
||
* as well as below the base glyph. The feature 'below-base
|
||
* form' will be applied to all such occurrences of Ra as well."
|
||
*
|
||
* Test case: U+0924,U+094D,U+0930,U+094d,U+0915
|
||
* with Sanskrit 2003 font.
|
||
*
|
||
* However, note that Ra,Halant,ZWJ is the correct way to
|
||
* request eyelash form of Ra, so we wouldbn't inhibit it
|
||
* in that sequence.
|
||
*
|
||
* Test case: U+0924,U+094D,U+0930,U+094d,U+200D,U+0915
|
||
*/
|
||
for (unsigned int i = start; i + 1 < base; i++)
|
||
if (info[i ].indic_category() == OT_Ra &&
|
||
info[i+1].indic_category() == OT_H &&
|
||
(i + 2 == base ||
|
||
info[i+2].indic_category() != OT_ZWJ))
|
||
{
|
||
info[i ].mask |= indic_plan->mask_array[INDIC_BLWF];
|
||
info[i+1].mask |= indic_plan->mask_array[INDIC_BLWF];
|
||
}
|
||
}
|
||
|
||
unsigned int pref_len = 2;
|
||
if (indic_plan->mask_array[INDIC_PREF] && base + pref_len < end)
|
||
{
|
||
/* Find a Halant,Ra sequence and mark it for pre-base-reordering processing. */
|
||
for (unsigned int i = base + 1; i + pref_len - 1 < end; i++) {
|
||
hb_codepoint_t glyphs[2];
|
||
for (unsigned int j = 0; j < pref_len; j++)
|
||
glyphs[j] = info[i + j].codepoint;
|
||
if (indic_plan->pref.would_substitute (glyphs, pref_len, face))
|
||
{
|
||
for (unsigned int j = 0; j < pref_len; j++)
|
||
info[i++].mask |= indic_plan->mask_array[INDIC_PREF];
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Apply ZWJ/ZWNJ effects */
|
||
for (unsigned int i = start + 1; i < end; i++)
|
||
if (is_joiner (info[i])) {
|
||
bool non_joiner = info[i].indic_category() == OT_ZWNJ;
|
||
unsigned int j = i;
|
||
|
||
do {
|
||
j--;
|
||
|
||
/* ZWJ/ZWNJ should disable CJCT. They do that by simply
|
||
* being there, since we don't skip them for the CJCT
|
||
* feature (ie. F_MANUAL_ZWJ) */
|
||
|
||
/* A ZWNJ disables HALF. */
|
||
if (non_joiner)
|
||
info[j].mask &= ~indic_plan->mask_array[INDIC_HALF];
|
||
|
||
} while (j > start && !is_consonant (info[j]));
|
||
}
|
||
}
|
||
|
||
static void
|
||
initial_reordering_standalone_cluster (const hb_ot_shape_plan_t *plan,
|
||
hb_face_t *face,
|
||
hb_buffer_t *buffer,
|
||
unsigned int start, unsigned int end)
|
||
{
|
||
/* We treat placeholder/dotted-circle as if they are consonants, so we
|
||
* should just chain. Only if not in compatibility mode that is... */
|
||
|
||
const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
|
||
if (indic_plan->uniscribe_bug_compatible)
|
||
{
|
||
/* For dotted-circle, this is what Uniscribe does:
|
||
* If dotted-circle is the last glyph, it just does nothing.
|
||
* Ie. It doesn't form Reph. */
|
||
if (buffer->info[end - 1].indic_category() == OT_DOTTEDCIRCLE)
|
||
return;
|
||
}
|
||
|
||
initial_reordering_consonant_syllable (plan, face, buffer, start, end);
|
||
}
|
||
|
||
static void
|
||
initial_reordering_syllable_indic (const hb_ot_shape_plan_t *plan,
|
||
hb_face_t *face,
|
||
hb_buffer_t *buffer,
|
||
unsigned int start, unsigned int end)
|
||
{
|
||
indic_syllable_type_t syllable_type = (indic_syllable_type_t) (buffer->info[start].syllable() & 0x0F);
|
||
switch (syllable_type)
|
||
{
|
||
case indic_vowel_syllable: /* We made the vowels look like consonants. So let's call the consonant logic! */
|
||
case indic_consonant_syllable:
|
||
initial_reordering_consonant_syllable (plan, face, buffer, start, end);
|
||
break;
|
||
|
||
case indic_broken_cluster: /* We already inserted dotted-circles, so just call the standalone_cluster. */
|
||
case indic_standalone_cluster:
|
||
initial_reordering_standalone_cluster (plan, face, buffer, start, end);
|
||
break;
|
||
|
||
case indic_symbol_cluster:
|
||
case indic_non_indic_cluster:
|
||
break;
|
||
}
|
||
}
|
||
|
||
static void
|
||
initial_reordering_indic (const hb_ot_shape_plan_t *plan,
|
||
hb_font_t *font,
|
||
hb_buffer_t *buffer)
|
||
{
|
||
if (!buffer->message (font, "start reordering indic initial"))
|
||
return;
|
||
|
||
update_consonant_positions_indic (plan, font, buffer);
|
||
hb_syllabic_insert_dotted_circles (font, buffer,
|
||
indic_broken_cluster,
|
||
OT_DOTTEDCIRCLE,
|
||
OT_Repha,
|
||
POS_END);
|
||
|
||
foreach_syllable (buffer, start, end)
|
||
initial_reordering_syllable_indic (plan, font->face, buffer, start, end);
|
||
|
||
(void) buffer->message (font, "end reordering indic initial");
|
||
}
|
||
|
||
static void
|
||
final_reordering_syllable_indic (const hb_ot_shape_plan_t *plan,
|
||
hb_buffer_t *buffer,
|
||
unsigned int start, unsigned int end)
|
||
{
|
||
const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
|
||
hb_glyph_info_t *info = buffer->info;
|
||
|
||
|
||
/* This function relies heavily on halant glyphs. Lots of ligation
|
||
* and possibly multiple substitutions happened prior to this
|
||
* phase, and that might have messed up our properties. Recover
|
||
* from a particular case of that where we're fairly sure that a
|
||
* class of OT_H is desired but has been lost. */
|
||
/* We don't call load_virama_glyph(), since we know it's already
|
||
* loaded. */
|
||
hb_codepoint_t virama_glyph = indic_plan->virama_glyph.get_relaxed ();
|
||
if (virama_glyph)
|
||
{
|
||
for (unsigned int i = start; i < end; i++)
|
||
if (info[i].codepoint == virama_glyph &&
|
||
_hb_glyph_info_ligated (&info[i]) &&
|
||
_hb_glyph_info_multiplied (&info[i]))
|
||
{
|
||
/* This will make sure that this glyph passes is_halant() test. */
|
||
info[i].indic_category() = OT_H;
|
||
_hb_glyph_info_clear_ligated_and_multiplied (&info[i]);
|
||
}
|
||
}
|
||
|
||
|
||
/* 4. Final reordering:
|
||
*
|
||
* After the localized forms and basic shaping forms GSUB features have been
|
||
* applied (see below), the shaping engine performs some final glyph
|
||
* reordering before applying all the remaining font features to the entire
|
||
* syllable.
|
||
*/
|
||
|
||
bool try_pref = !!indic_plan->mask_array[INDIC_PREF];
|
||
|
||
/* Find base again */
|
||
unsigned int base;
|
||
for (base = start; base < end; base++)
|
||
if (info[base].indic_position() >= POS_BASE_C)
|
||
{
|
||
if (try_pref && base + 1 < end)
|
||
{
|
||
for (unsigned int i = base + 1; i < end; i++)
|
||
if ((info[i].mask & indic_plan->mask_array[INDIC_PREF]) != 0)
|
||
{
|
||
if (!(_hb_glyph_info_substituted (&info[i]) &&
|
||
_hb_glyph_info_ligated_and_didnt_multiply (&info[i])))
|
||
{
|
||
/* Ok, this was a 'pref' candidate but didn't form any.
|
||
* Base is around here... */
|
||
base = i;
|
||
while (base < end && is_halant (info[base]))
|
||
base++;
|
||
info[base].indic_position() = POS_BASE_C;
|
||
|
||
try_pref = false;
|
||
}
|
||
break;
|
||
}
|
||
}
|
||
/* For Malayalam, skip over unformed below- (but NOT post-) forms. */
|
||
if (buffer->props.script == HB_SCRIPT_MALAYALAM)
|
||
{
|
||
for (unsigned int i = base + 1; i < end; i++)
|
||
{
|
||
while (i < end && is_joiner (info[i]))
|
||
i++;
|
||
if (i == end || !is_halant (info[i]))
|
||
break;
|
||
i++; /* Skip halant. */
|
||
while (i < end && is_joiner (info[i]))
|
||
i++;
|
||
if (i < end && is_consonant (info[i]) && info[i].indic_position() == POS_BELOW_C)
|
||
{
|
||
base = i;
|
||
info[base].indic_position() = POS_BASE_C;
|
||
}
|
||
}
|
||
}
|
||
|
||
if (start < base && info[base].indic_position() > POS_BASE_C)
|
||
base--;
|
||
break;
|
||
}
|
||
if (base == end && start < base &&
|
||
is_one_of (info[base - 1], FLAG (OT_ZWJ)))
|
||
base--;
|
||
if (base < end)
|
||
while (start < base &&
|
||
is_one_of (info[base], (FLAG (OT_N) | FLAG (OT_H))))
|
||
base--;
|
||
|
||
|
||
/* o Reorder matras:
|
||
*
|
||
* If a pre-base matra character had been reordered before applying basic
|
||
* features, the glyph can be moved closer to the main consonant based on
|
||
* whether half-forms had been formed. Actual position for the matra is
|
||
* defined as “after last standalone halant glyph, after initial matra
|
||
* position and before the main consonant”. If ZWJ or ZWNJ follow this
|
||
* halant, position is moved after it.
|
||
*
|
||
* IMPLEMENTATION NOTES:
|
||
*
|
||
* It looks like the last sentence is wrong. Testing, with Windows 7 Uniscribe
|
||
* and Devanagari shows that the behavior is best described as:
|
||
*
|
||
* "If ZWJ follows this halant, matra is NOT repositioned after this halant.
|
||
* If ZWNJ follows this halant, position is moved after it."
|
||
*
|
||
* Test case, with Adobe Devanagari or Nirmala UI:
|
||
*
|
||
* U+091F,U+094D,U+200C,U+092F,U+093F
|
||
* (Matra moves to the middle, after ZWNJ.)
|
||
*
|
||
* U+091F,U+094D,U+200D,U+092F,U+093F
|
||
* (Matra does NOT move, stays to the left.)
|
||
*
|
||
* https://github.com/harfbuzz/harfbuzz/issues/1070
|
||
*/
|
||
|
||
if (start + 1 < end && start < base) /* Otherwise there can't be any pre-base matra characters. */
|
||
{
|
||
/* If we lost track of base, alas, position before last thingy. */
|
||
unsigned int new_pos = base == end ? base - 2 : base - 1;
|
||
|
||
/* Malayalam / Tamil do not have "half" forms or explicit virama forms.
|
||
* The glyphs formed by 'half' are Chillus or ligated explicit viramas.
|
||
* We want to position matra after them.
|
||
*/
|
||
if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL)
|
||
{
|
||
search:
|
||
while (new_pos > start &&
|
||
!(is_one_of (info[new_pos], (FLAG (OT_M) | FLAG (OT_H)))))
|
||
new_pos--;
|
||
|
||
/* If we found no Halant we are done.
|
||
* Otherwise only proceed if the Halant does
|
||
* not belong to the Matra itself! */
|
||
if (is_halant (info[new_pos]) &&
|
||
info[new_pos].indic_position() != POS_PRE_M)
|
||
{
|
||
#if 0 // See comment above
|
||
/* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */
|
||
if (new_pos + 1 < end && is_joiner (info[new_pos + 1]))
|
||
new_pos++;
|
||
#endif
|
||
if (new_pos + 1 < end)
|
||
{
|
||
/* -> If ZWJ follows this halant, matra is NOT repositioned after this halant. */
|
||
if (info[new_pos + 1].indic_category() == OT_ZWJ)
|
||
{
|
||
/* Keep searching. */
|
||
if (new_pos > start)
|
||
{
|
||
new_pos--;
|
||
goto search;
|
||
}
|
||
}
|
||
/* -> If ZWNJ follows this halant, position is moved after it.
|
||
*
|
||
* IMPLEMENTATION NOTES:
|
||
*
|
||
* This is taken care of by the state-machine. A Halant,ZWNJ is a terminating
|
||
* sequence for a consonant syllable; any pre-base matras occurring after it
|
||
* will belong to the subsequent syllable.
|
||
*/
|
||
}
|
||
}
|
||
else
|
||
new_pos = start; /* No move. */
|
||
}
|
||
|
||
if (start < new_pos && info[new_pos].indic_position () != POS_PRE_M)
|
||
{
|
||
/* Now go see if there's actually any matras... */
|
||
for (unsigned int i = new_pos; i > start; i--)
|
||
if (info[i - 1].indic_position () == POS_PRE_M)
|
||
{
|
||
unsigned int old_pos = i - 1;
|
||
if (old_pos < base && base <= new_pos) /* Shouldn't actually happen. */
|
||
base--;
|
||
|
||
hb_glyph_info_t tmp = info[old_pos];
|
||
memmove (&info[old_pos], &info[old_pos + 1], (new_pos - old_pos) * sizeof (info[0]));
|
||
info[new_pos] = tmp;
|
||
|
||
/* Note: this merge_clusters() is intentionally *after* the reordering.
|
||
* Indic matra reordering is special and tricky... */
|
||
buffer->merge_clusters (new_pos, hb_min (end, base + 1));
|
||
|
||
new_pos--;
|
||
}
|
||
} else {
|
||
for (unsigned int i = start; i < base; i++)
|
||
if (info[i].indic_position () == POS_PRE_M) {
|
||
buffer->merge_clusters (i, hb_min (end, base + 1));
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
|
||
/* o Reorder reph:
|
||
*
|
||
* Reph’s original position is always at the beginning of the syllable,
|
||
* (i.e. it is not reordered at the character reordering stage). However,
|
||
* it will be reordered according to the basic-forms shaping results.
|
||
* Possible positions for reph, depending on the script, are; after main,
|
||
* before post-base consonant forms, and after post-base consonant forms.
|
||
*/
|
||
|
||
/* Two cases:
|
||
*
|
||
* - If repha is encoded as a sequence of characters (Ra,H or Ra,H,ZWJ), then
|
||
* we should only move it if the sequence ligated to the repha form.
|
||
*
|
||
* - If repha is encoded separately and in the logical position, we should only
|
||
* move it if it did NOT ligate. If it ligated, it's probably the font trying
|
||
* to make it work without the reordering.
|
||
*/
|
||
if (start + 1 < end &&
|
||
info[start].indic_position() == POS_RA_TO_BECOME_REPH &&
|
||
((info[start].indic_category() == OT_Repha) ^
|
||
_hb_glyph_info_ligated_and_didnt_multiply (&info[start])))
|
||
{
|
||
unsigned int new_reph_pos;
|
||
reph_position_t reph_pos = indic_plan->config->reph_pos;
|
||
|
||
/* 1. If reph should be positioned after post-base consonant forms,
|
||
* proceed to step 5.
|
||
*/
|
||
if (reph_pos == REPH_POS_AFTER_POST)
|
||
{
|
||
goto reph_step_5;
|
||
}
|
||
|
||
/* 2. If the reph repositioning class is not after post-base: target
|
||
* position is after the first explicit halant glyph between the
|
||
* first post-reph consonant and last main consonant. If ZWJ or ZWNJ
|
||
* are following this halant, position is moved after it. If such
|
||
* position is found, this is the target position. Otherwise,
|
||
* proceed to the next step.
|
||
*
|
||
* Note: in old-implementation fonts, where classifications were
|
||
* fixed in shaping engine, there was no case where reph position
|
||
* will be found on this step.
|
||
*/
|
||
{
|
||
new_reph_pos = start + 1;
|
||
while (new_reph_pos < base && !is_halant (info[new_reph_pos]))
|
||
new_reph_pos++;
|
||
|
||
if (new_reph_pos < base && is_halant (info[new_reph_pos]))
|
||
{
|
||
/* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */
|
||
if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1]))
|
||
new_reph_pos++;
|
||
goto reph_move;
|
||
}
|
||
}
|
||
|
||
/* 3. If reph should be repositioned after the main consonant: find the
|
||
* first consonant not ligated with main, or find the first
|
||
* consonant that is not a potential pre-base-reordering Ra.
|
||
*/
|
||
if (reph_pos == REPH_POS_AFTER_MAIN)
|
||
{
|
||
new_reph_pos = base;
|
||
while (new_reph_pos + 1 < end && info[new_reph_pos + 1].indic_position() <= POS_AFTER_MAIN)
|
||
new_reph_pos++;
|
||
if (new_reph_pos < end)
|
||
goto reph_move;
|
||
}
|
||
|
||
/* 4. If reph should be positioned before post-base consonant, find
|
||
* first post-base classified consonant not ligated with main. If no
|
||
* consonant is found, the target position should be before the
|
||
* first matra, syllable modifier sign or vedic sign.
|
||
*/
|
||
/* This is our take on what step 4 is trying to say (and failing, BADLY). */
|
||
if (reph_pos == REPH_POS_AFTER_SUB)
|
||
{
|
||
new_reph_pos = base;
|
||
while (new_reph_pos + 1 < end &&
|
||
!( FLAG_UNSAFE (info[new_reph_pos + 1].indic_position()) & (FLAG (POS_POST_C) | FLAG (POS_AFTER_POST) | FLAG (POS_SMVD))))
|
||
new_reph_pos++;
|
||
if (new_reph_pos < end)
|
||
goto reph_move;
|
||
}
|
||
|
||
/* 5. If no consonant is found in steps 3 or 4, move reph to a position
|
||
* immediately before the first post-base matra, syllable modifier
|
||
* sign or vedic sign that has a reordering class after the intended
|
||
* reph position. For example, if the reordering position for reph
|
||
* is post-main, it will skip above-base matras that also have a
|
||
* post-main position.
|
||
*/
|
||
reph_step_5:
|
||
{
|
||
/* Copied from step 2. */
|
||
new_reph_pos = start + 1;
|
||
while (new_reph_pos < base && !is_halant (info[new_reph_pos]))
|
||
new_reph_pos++;
|
||
|
||
if (new_reph_pos < base && is_halant (info[new_reph_pos]))
|
||
{
|
||
/* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */
|
||
if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1]))
|
||
new_reph_pos++;
|
||
goto reph_move;
|
||
}
|
||
}
|
||
/* See https://github.com/harfbuzz/harfbuzz/issues/2298#issuecomment-615318654 */
|
||
|
||
/* 6. Otherwise, reorder reph to the end of the syllable.
|
||
*/
|
||
{
|
||
new_reph_pos = end - 1;
|
||
while (new_reph_pos > start && info[new_reph_pos].indic_position() == POS_SMVD)
|
||
new_reph_pos--;
|
||
|
||
/*
|
||
* If the Reph is to be ending up after a Matra,Halant sequence,
|
||
* position it before that Halant so it can interact with the Matra.
|
||
* However, if it's a plain Consonant,Halant we shouldn't do that.
|
||
* Uniscribe doesn't do this.
|
||
* TEST: U+0930,U+094D,U+0915,U+094B,U+094D
|
||
*/
|
||
if (!indic_plan->uniscribe_bug_compatible &&
|
||
unlikely (is_halant (info[new_reph_pos])))
|
||
{
|
||
for (unsigned int i = base + 1; i < new_reph_pos; i++)
|
||
if (info[i].indic_category() == OT_M) {
|
||
/* Ok, got it. */
|
||
new_reph_pos--;
|
||
}
|
||
}
|
||
|
||
goto reph_move;
|
||
}
|
||
|
||
reph_move:
|
||
{
|
||
/* Move */
|
||
buffer->merge_clusters (start, new_reph_pos + 1);
|
||
hb_glyph_info_t reph = info[start];
|
||
memmove (&info[start], &info[start + 1], (new_reph_pos - start) * sizeof (info[0]));
|
||
info[new_reph_pos] = reph;
|
||
|
||
if (start < base && base <= new_reph_pos)
|
||
base--;
|
||
}
|
||
}
|
||
|
||
|
||
/* o Reorder pre-base-reordering consonants:
|
||
*
|
||
* If a pre-base-reordering consonant is found, reorder it according to
|
||
* the following rules:
|
||
*/
|
||
|
||
if (try_pref && base + 1 < end) /* Otherwise there can't be any pre-base-reordering Ra. */
|
||
{
|
||
for (unsigned int i = base + 1; i < end; i++)
|
||
if ((info[i].mask & indic_plan->mask_array[INDIC_PREF]) != 0)
|
||
{
|
||
/* 1. Only reorder a glyph produced by substitution during application
|
||
* of the <pref> feature. (Note that a font may shape a Ra consonant with
|
||
* the feature generally but block it in certain contexts.)
|
||
*/
|
||
/* Note: We just check that something got substituted. We don't check that
|
||
* the <pref> feature actually did it...
|
||
*
|
||
* Reorder pref only if it ligated. */
|
||
if (_hb_glyph_info_ligated_and_didnt_multiply (&info[i]))
|
||
{
|
||
/*
|
||
* 2. Try to find a target position the same way as for pre-base matra.
|
||
* If it is found, reorder pre-base consonant glyph.
|
||
*
|
||
* 3. If position is not found, reorder immediately before main
|
||
* consonant.
|
||
*/
|
||
|
||
unsigned int new_pos = base;
|
||
/* Malayalam / Tamil do not have "half" forms or explicit virama forms.
|
||
* The glyphs formed by 'half' are Chillus or ligated explicit viramas.
|
||
* We want to position matra after them.
|
||
*/
|
||
if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL)
|
||
{
|
||
while (new_pos > start &&
|
||
!(is_one_of (info[new_pos - 1], FLAG(OT_M) | FLAG (OT_H))))
|
||
new_pos--;
|
||
}
|
||
|
||
if (new_pos > start && is_halant (info[new_pos - 1]))
|
||
{
|
||
/* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */
|
||
if (new_pos < end && is_joiner (info[new_pos]))
|
||
new_pos++;
|
||
}
|
||
|
||
{
|
||
unsigned int old_pos = i;
|
||
|
||
buffer->merge_clusters (new_pos, old_pos + 1);
|
||
hb_glyph_info_t tmp = info[old_pos];
|
||
memmove (&info[new_pos + 1], &info[new_pos], (old_pos - new_pos) * sizeof (info[0]));
|
||
info[new_pos] = tmp;
|
||
|
||
if (new_pos <= base && base < old_pos)
|
||
base++;
|
||
}
|
||
}
|
||
|
||
break;
|
||
}
|
||
}
|
||
|
||
|
||
/* Apply 'init' to the Left Matra if it's a word start. */
|
||
if (info[start].indic_position () == POS_PRE_M)
|
||
{
|
||
if (!start ||
|
||
!(FLAG_UNSAFE (_hb_glyph_info_get_general_category (&info[start - 1])) &
|
||
FLAG_RANGE (HB_UNICODE_GENERAL_CATEGORY_FORMAT, HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)))
|
||
info[start].mask |= indic_plan->mask_array[INDIC_INIT];
|
||
else
|
||
buffer->unsafe_to_break (start - 1, start + 1);
|
||
}
|
||
|
||
|
||
/*
|
||
* Finish off the clusters and go home!
|
||
*/
|
||
if (indic_plan->uniscribe_bug_compatible)
|
||
{
|
||
switch ((hb_tag_t) plan->props.script)
|
||
{
|
||
case HB_SCRIPT_TAMIL:
|
||
case HB_SCRIPT_SINHALA:
|
||
break;
|
||
|
||
default:
|
||
/* Uniscribe merges the entire syllable into a single cluster... Except for Tamil & Sinhala.
|
||
* This means, half forms are submerged into the main consonant's cluster.
|
||
* This is unnecessary, and makes cursor positioning harder, but that's what
|
||
* Uniscribe does. */
|
||
buffer->merge_clusters (start, end);
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
|
||
static void
|
||
final_reordering_indic (const hb_ot_shape_plan_t *plan,
|
||
hb_font_t *font HB_UNUSED,
|
||
hb_buffer_t *buffer)
|
||
{
|
||
unsigned int count = buffer->len;
|
||
if (unlikely (!count)) return;
|
||
|
||
if (buffer->message (font, "start reordering indic final")) {
|
||
foreach_syllable (buffer, start, end)
|
||
final_reordering_syllable_indic (plan, buffer, start, end);
|
||
(void) buffer->message (font, "end reordering indic final");
|
||
}
|
||
|
||
HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category);
|
||
HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position);
|
||
}
|
||
|
||
|
||
static void
|
||
preprocess_text_indic (const hb_ot_shape_plan_t *plan,
|
||
hb_buffer_t *buffer,
|
||
hb_font_t *font)
|
||
{
|
||
_hb_preprocess_text_vowel_constraints (plan, buffer, font);
|
||
}
|
||
|
||
static bool
|
||
decompose_indic (const hb_ot_shape_normalize_context_t *c,
|
||
hb_codepoint_t ab,
|
||
hb_codepoint_t *a,
|
||
hb_codepoint_t *b)
|
||
{
|
||
switch (ab)
|
||
{
|
||
/* Don't decompose these. */
|
||
case 0x0931u : return false; /* DEVANAGARI LETTER RRA */
|
||
// https://github.com/harfbuzz/harfbuzz/issues/779
|
||
case 0x09DCu : return false; /* BENGALI LETTER RRA */
|
||
case 0x09DDu : return false; /* BENGALI LETTER RHA */
|
||
case 0x0B94u : return false; /* TAMIL LETTER AU */
|
||
|
||
|
||
/*
|
||
* Decompose split matras that don't have Unicode decompositions.
|
||
*/
|
||
|
||
#if 0
|
||
/* Gujarati */
|
||
/* This one has no decomposition in Unicode, but needs no decomposition either. */
|
||
/* case 0x0AC9u : return false; */
|
||
|
||
/* Oriya */
|
||
case 0x0B57u : *a = no decomp, -> RIGHT; return true;
|
||
#endif
|
||
}
|
||
|
||
if ((ab == 0x0DDAu || hb_in_range<hb_codepoint_t> (ab, 0x0DDCu, 0x0DDEu)))
|
||
{
|
||
/*
|
||
* Sinhala split matras... Let the fun begin.
|
||
*
|
||
* These four characters have Unicode decompositions. However, Uniscribe
|
||
* decomposes them "Khmer-style", that is, it uses the character itself to
|
||
* get the second half. The first half of all four decompositions is always
|
||
* U+0DD9.
|
||
*
|
||
* Now, there are buggy fonts, namely, the widely used lklug.ttf, that are
|
||
* broken with Uniscribe. But we need to support them. As such, we only
|
||
* do the Uniscribe-style decomposition if the character is transformed into
|
||
* its "sec.half" form by the 'pstf' feature. Otherwise, we fall back to
|
||
* Unicode decomposition.
|
||
*
|
||
* Note that we can't unconditionally use Unicode decomposition. That would
|
||
* break some other fonts, that are designed to work with Uniscribe, and
|
||
* don't have positioning features for the Unicode-style decomposition.
|
||
*
|
||
* Argh...
|
||
*
|
||
* The Uniscribe behavior is now documented in the newly published Sinhala
|
||
* spec in 2012:
|
||
*
|
||
* https://docs.microsoft.com/en-us/typography/script-development/sinhala#shaping
|
||
*/
|
||
|
||
|
||
const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) c->plan->data;
|
||
hb_codepoint_t glyph;
|
||
if (indic_plan->uniscribe_bug_compatible ||
|
||
(c->font->get_nominal_glyph (ab, &glyph) &&
|
||
indic_plan->pstf.would_substitute (&glyph, 1, c->font->face)))
|
||
{
|
||
/* Ok, safe to use Uniscribe-style decomposition. */
|
||
*a = 0x0DD9u;
|
||
*b = ab;
|
||
return true;
|
||
}
|
||
}
|
||
|
||
return (bool) c->unicode->decompose (ab, a, b);
|
||
}
|
||
|
||
static bool
|
||
compose_indic (const hb_ot_shape_normalize_context_t *c,
|
||
hb_codepoint_t a,
|
||
hb_codepoint_t b,
|
||
hb_codepoint_t *ab)
|
||
{
|
||
/* Avoid recomposing split matras. */
|
||
if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (c->unicode->general_category (a)))
|
||
return false;
|
||
|
||
/* Composition-exclusion exceptions that we want to recompose. */
|
||
if (a == 0x09AFu && b == 0x09BCu) { *ab = 0x09DFu; return true; }
|
||
|
||
return (bool) c->unicode->compose (a, b, ab);
|
||
}
|
||
|
||
|
||
const hb_ot_complex_shaper_t _hb_ot_complex_shaper_indic =
|
||
{
|
||
collect_features_indic,
|
||
override_features_indic,
|
||
data_create_indic,
|
||
data_destroy_indic,
|
||
preprocess_text_indic,
|
||
nullptr, /* postprocess_glyphs */
|
||
HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
|
||
decompose_indic,
|
||
compose_indic,
|
||
setup_masks_indic,
|
||
HB_TAG_NONE, /* gpos_tag */
|
||
nullptr, /* reorder_marks */
|
||
HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
|
||
false, /* fallback_position */
|
||
};
|
||
|
||
|
||
#endif
|