harfbuzz/src/hb-ot-shape-complex-myanmar.cc

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/*
* Copyright © 2011,2012,2013 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
*/
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#include "hb-ot-shape-complex-myanmar-private.hh"
/*
* Myanmar shaper.
*/
static const hb_tag_t
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basic_features[] =
{
/*
* Basic features.
* These features are applied in order, one at a time, after initial_reordering.
*/
HB_TAG('r','p','h','f'),
HB_TAG('p','r','e','f'),
HB_TAG('b','l','w','f'),
HB_TAG('p','s','t','f'),
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};
static const hb_tag_t
other_features[] =
{
/*
* Other features.
* These features are applied all at once, after final_reordering.
*/
HB_TAG('p','r','e','s'),
HB_TAG('a','b','v','s'),
HB_TAG('b','l','w','s'),
HB_TAG('p','s','t','s'),
/* Positioning features, though we don't care about the types. */
HB_TAG('d','i','s','t'),
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/* Pre-release version of Windows 8 Myanmar font had abvm,blwm
* features. The released Windows 8 version of the font (as well
* as the released spec) used 'mark' instead. The Windows 8
* shaper however didn't apply 'mark' but did apply 'mkmk'.
* Perhaps it applied abvm/blwm. This was fixed in a Windows 8
* update, so now it applies mark/mkmk. We are guessing that
* it still applies abvm/blwm too.
*/
HB_TAG('a','b','v','m'),
HB_TAG('b','l','w','m'),
};
static void
setup_syllables (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer);
static void
initial_reordering (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer);
static void
final_reordering (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer);
static void
collect_features_myanmar (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);
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map->add_global_bool_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. */
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map->add_global_bool_feature (HB_TAG('c','c','m','p'));
map->add_gsub_pause (initial_reordering);
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for (unsigned int i = 0; i < ARRAY_LENGTH (basic_features); i++)
{
[Indic] Futher adjust ZWJ handling in Indic-like shapers After the Ngapi hackfest work, we were assuming that fonts won't use presentation features to choose specific forms (eg. conjuncts). As such, we were using auto-joiner behavior for such features. It proved to be troublesome as many fonts used presentation forms ('pres') for example to form conjuncts, which need to be disabled when a ZWJ is inserted. Two examples: U+0D2F,U+200D,U+0D4D,U+0D2F with kartika.ttf U+0995,U+09CD,U+200D,U+09B7 with vrinda.ttf What we do now is to never do magic to ZWJ during GSUB's main input match for Indic-style shapers. Note that backtrack/lookahead are still matched liberally, as is GPOS. This seems to be an acceptable compromise. As to the bug that initially started this work, that one needs to be fixed differently: Bug 58714 - Kannada u+0cb0 u+200d u+0ccd u+0c95 u+0cbe does not provide same results as Windows8 https://bugs.freedesktop.org/show_bug.cgi?id=58714 New numbers: BENGALI: 353689 out of 354188 tests passed. 499 failed (0.140886%) DEVANAGARI: 707305 out of 707394 tests passed. 89 failed (0.0125814%) GUJARATI: 366349 out of 366457 tests passed. 108 failed (0.0294714%) GURMUKHI: 60706 out of 60747 tests passed. 41 failed (0.067493%) KANNADA: 951030 out of 951913 tests passed. 883 failed (0.0927606%) KHMER: 299070 out of 299124 tests passed. 54 failed (0.0180527%) LAO: 53611 out of 53644 tests passed. 33 failed (0.0615167%) MALAYALAM: 1048102 out of 1048334 tests passed. 232 failed (0.0221304%) ORIYA: 42320 out of 42329 tests passed. 9 failed (0.021262%) SINHALA: 271666 out of 271847 tests passed. 181 failed (0.0665816%) TAMIL: 1091753 out of 1091754 tests passed. 1 failed (9.15957e-05%) TELUGU: 970555 out of 970573 tests passed. 18 failed (0.00185457%) TIBETAN: 208469 out of 208469 tests passed. 0 failed (0%)
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map->add_feature (basic_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);
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map->add_gsub_pause (nullptr);
}
map->add_gsub_pause (final_reordering);
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for (unsigned int i = 0; i < ARRAY_LENGTH (other_features); i++)
[Indic] Futher adjust ZWJ handling in Indic-like shapers After the Ngapi hackfest work, we were assuming that fonts won't use presentation features to choose specific forms (eg. conjuncts). As such, we were using auto-joiner behavior for such features. It proved to be troublesome as many fonts used presentation forms ('pres') for example to form conjuncts, which need to be disabled when a ZWJ is inserted. Two examples: U+0D2F,U+200D,U+0D4D,U+0D2F with kartika.ttf U+0995,U+09CD,U+200D,U+09B7 with vrinda.ttf What we do now is to never do magic to ZWJ during GSUB's main input match for Indic-style shapers. Note that backtrack/lookahead are still matched liberally, as is GPOS. This seems to be an acceptable compromise. As to the bug that initially started this work, that one needs to be fixed differently: Bug 58714 - Kannada u+0cb0 u+200d u+0ccd u+0c95 u+0cbe does not provide same results as Windows8 https://bugs.freedesktop.org/show_bug.cgi?id=58714 New numbers: BENGALI: 353689 out of 354188 tests passed. 499 failed (0.140886%) DEVANAGARI: 707305 out of 707394 tests passed. 89 failed (0.0125814%) GUJARATI: 366349 out of 366457 tests passed. 108 failed (0.0294714%) GURMUKHI: 60706 out of 60747 tests passed. 41 failed (0.067493%) KANNADA: 951030 out of 951913 tests passed. 883 failed (0.0927606%) KHMER: 299070 out of 299124 tests passed. 54 failed (0.0180527%) LAO: 53611 out of 53644 tests passed. 33 failed (0.0615167%) MALAYALAM: 1048102 out of 1048334 tests passed. 232 failed (0.0221304%) ORIYA: 42320 out of 42329 tests passed. 9 failed (0.021262%) SINHALA: 271666 out of 271847 tests passed. 181 failed (0.0665816%) TAMIL: 1091753 out of 1091754 tests passed. 1 failed (9.15957e-05%) TELUGU: 970555 out of 970573 tests passed. 18 failed (0.00185457%) TIBETAN: 208469 out of 208469 tests passed. 0 failed (0%)
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map->add_feature (other_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);
}
static void
override_features_myanmar (hb_ot_shape_planner_t *plan)
{
plan->map.add_feature (HB_TAG('l','i','g','a'), 0, F_GLOBAL);
}
enum syllable_type_t {
consonant_syllable,
punctuation_cluster,
broken_cluster,
non_myanmar_cluster,
};
#include "hb-ot-shape-complex-myanmar-machine.hh"
static void
setup_masks_myanmar (const hb_ot_shape_plan_t *plan HB_UNUSED,
hb_buffer_t *buffer,
hb_font_t *font HB_UNUSED)
{
HB_BUFFER_ALLOCATE_VAR (buffer, myanmar_category);
HB_BUFFER_ALLOCATE_VAR (buffer, myanmar_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;
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hb_glyph_info_t *info = buffer->info;
for (unsigned int i = 0; i < count; i++)
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set_myanmar_properties (info[i]);
}
static void
setup_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED,
hb_font_t *font HB_UNUSED,
hb_buffer_t *buffer)
{
find_syllables (buffer);
foreach_syllable (buffer, start, end)
buffer->unsafe_to_break (start, end);
}
static int
compare_myanmar_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb)
{
int a = pa->myanmar_position();
int b = pb->myanmar_position();
return a < b ? -1 : a == b ? 0 : +1;
}
/* Rules from:
* https://docs.microsoft.com/en-us/typography/script-development/myanmar */
static void
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initial_reordering_consonant_syllable (hb_buffer_t *buffer,
unsigned int start, unsigned int end)
{
hb_glyph_info_t *info = buffer->info;
unsigned int base = end;
bool has_reph = false;
{
unsigned int limit = start;
if (start + 3 <= end &&
info[start ].myanmar_category() == OT_Ra &&
info[start+1].myanmar_category() == OT_As &&
info[start+2].myanmar_category() == OT_H)
{
limit += 3;
base = start;
has_reph = true;
}
{
if (!has_reph)
base = limit;
for (unsigned int i = limit; i < end; i++)
if (is_consonant (info[i]))
{
base = i;
break;
}
}
}
/* Reorder! */
{
unsigned int i = start;
for (; i < start + (has_reph ? 3 : 0); i++)
info[i].myanmar_position() = POS_AFTER_MAIN;
for (; i < base; i++)
info[i].myanmar_position() = POS_PRE_C;
if (i < end)
{
info[i].myanmar_position() = POS_BASE_C;
i++;
}
indic_position_t pos = POS_AFTER_MAIN;
/* The following loop may be ugly, but it implements all of
* Myanmar reordering! */
for (; i < end; i++)
{
if (info[i].myanmar_category() == OT_MR) /* Pre-base reordering */
{
info[i].myanmar_position() = POS_PRE_C;
continue;
}
if (info[i].myanmar_position() < POS_BASE_C) /* Left matra */
{
continue;
}
if (info[i].myanmar_category() == OT_VS)
{
info[i].myanmar_position() = info[i - 1].myanmar_position();
continue;
}
if (pos == POS_AFTER_MAIN && info[i].myanmar_category() == OT_VBlw)
{
pos = POS_BELOW_C;
info[i].myanmar_position() = pos;
continue;
}
if (pos == POS_BELOW_C && info[i].myanmar_category() == OT_A)
{
info[i].myanmar_position() = POS_BEFORE_SUB;
continue;
}
if (pos == POS_BELOW_C && info[i].myanmar_category() == OT_VBlw)
{
info[i].myanmar_position() = pos;
continue;
}
if (pos == POS_BELOW_C && info[i].myanmar_category() != OT_A)
{
pos = POS_AFTER_SUB;
info[i].myanmar_position() = pos;
continue;
}
info[i].myanmar_position() = pos;
}
}
/* Sit tight, rock 'n roll! */
buffer->sort (start, end, compare_myanmar_order);
}
static void
initial_reordering_syllable (const hb_ot_shape_plan_t *plan,
hb_face_t *face,
hb_buffer_t *buffer,
unsigned int start, unsigned int end)
{
syllable_type_t syllable_type = (syllable_type_t) (buffer->info[start].syllable() & 0x0F);
switch (syllable_type) {
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case broken_cluster: /* We already inserted dotted-circles, so just call the consonant_syllable. */
case consonant_syllable:
initial_reordering_consonant_syllable (buffer, start, end);
break;
case punctuation_cluster:
case non_myanmar_cluster:
break;
}
}
static inline void
insert_dotted_circles (const hb_ot_shape_plan_t *plan HB_UNUSED,
hb_font_t *font,
hb_buffer_t *buffer)
{
/* Note: This loop is extra overhead, but should not be measurable. */
bool has_broken_syllables = false;
unsigned int count = buffer->len;
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hb_glyph_info_t *info = buffer->info;
for (unsigned int i = 0; i < count; i++)
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if ((info[i].syllable() & 0x0F) == broken_cluster)
{
has_broken_syllables = true;
break;
}
if (likely (!has_broken_syllables))
return;
hb_codepoint_t dottedcircle_glyph;
if (!font->get_nominal_glyph (0x25CCu, &dottedcircle_glyph))
return;
hb_glyph_info_t dottedcircle = {0};
dottedcircle.codepoint = 0x25CCu;
set_myanmar_properties (dottedcircle);
dottedcircle.codepoint = dottedcircle_glyph;
buffer->clear_output ();
buffer->idx = 0;
unsigned int last_syllable = 0;
while (buffer->idx < buffer->len && !buffer->in_error)
{
unsigned int syllable = buffer->cur().syllable();
syllable_type_t syllable_type = (syllable_type_t) (syllable & 0x0F);
if (unlikely (last_syllable != syllable && syllable_type == broken_cluster))
{
last_syllable = syllable;
hb_glyph_info_t ginfo = dottedcircle;
ginfo.cluster = buffer->cur().cluster;
ginfo.mask = buffer->cur().mask;
ginfo.syllable() = buffer->cur().syllable();
buffer->output_info (ginfo);
}
else
buffer->next_glyph ();
}
buffer->swap_buffers ();
}
static void
initial_reordering (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer)
{
insert_dotted_circles (plan, font, buffer);
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foreach_syllable (buffer, start, end)
initial_reordering_syllable (plan, font->face, buffer, start, end);
}
static void
final_reordering (const hb_ot_shape_plan_t *plan,
hb_font_t *font HB_UNUSED,
hb_buffer_t *buffer)
{
hb_glyph_info_t *info = buffer->info;
unsigned int count = buffer->len;
/* Zero syllables now... */
for (unsigned int i = 0; i < count; i++)
info[i].syllable() = 0;
HB_BUFFER_DEALLOCATE_VAR (buffer, myanmar_category);
HB_BUFFER_DEALLOCATE_VAR (buffer, myanmar_position);
}
/* Uniscribe seems to have a shaper for 'mymr' that is like the
* generic shaper, except that it zeros mark advances GDEF_LATE. */
const hb_ot_complex_shaper_t _hb_ot_complex_shaper_myanmar_old =
{
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nullptr, /* collect_features */
nullptr, /* override_features */
nullptr, /* data_create */
nullptr, /* data_destroy */
nullptr, /* preprocess_text */
nullptr, /* postprocess_glyphs */
HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
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nullptr, /* decompose */
nullptr, /* compose */
nullptr, /* setup_masks */
nullptr, /* disable_otl */
nullptr, /* reorder_marks */
HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
true, /* fallback_position */
};
const hb_ot_complex_shaper_t _hb_ot_complex_shaper_myanmar =
{
collect_features_myanmar,
override_features_myanmar,
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nullptr, /* data_create */
nullptr, /* data_destroy */
nullptr, /* preprocess_text */
nullptr, /* postprocess_glyphs */
HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
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nullptr, /* decompose */
nullptr, /* compose */
setup_masks_myanmar,
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nullptr, /* disable_otl */
nullptr, /* reorder_marks */
HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY,
false, /* fallback_position */
};