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[khmer] Remove indic_config->base_pos

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pull/683/head
Behdad Esfahbod 7 years ago
parent 0c91638d48
commit ffcd6c7efd
1 changed files with 7 additions and 222 deletions
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  1. 229
      src/hb-ot-shape-complex-khmer.cc

229
src/hb-ot-shape-complex-khmer.cc
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@ -273,11 +273,6 @@ set_khmer_properties (hb_glyph_info_t &info)
* instead of adding a new flag in these structs.
*/
enum base_position_t {
BASE_POS_FIRST,
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,
@ -298,7 +293,6 @@ enum blwf_mode_t {
};
struct indic_config_t
{
base_position_t base_pos;
reph_position_t reph_pos;
reph_mode_t reph_mode;
blwf_mode_t blwf_mode;
@ -306,7 +300,7 @@ struct indic_config_t
static const indic_config_t indic_configs[] =
{
{BASE_POS_FIRST,REPH_POS_DONT_CARE, REPH_MODE_VIS_REPHA,BLWF_MODE_PRE_AND_POST},
{REPH_POS_DONT_CARE, REPH_MODE_VIS_REPHA,BLWF_MODE_PRE_AND_POST},
};
@ -504,8 +498,6 @@ struct khmer_shape_plan_t
would_substitute_feature_t rphf;
would_substitute_feature_t pref;
would_substitute_feature_t blwf;
would_substitute_feature_t pstf;
hb_mask_t mask_array[INDIC_NUM_FEATURES];
};
@ -523,8 +515,6 @@ data_create_khmer (const hb_ot_shape_plan_t *plan)
khmer_plan->rphf.init (&plan->map, HB_TAG('r','p','h','f'), true);
khmer_plan->pref.init (&plan->map, HB_TAG('p','r','e','f'), true);
khmer_plan->blwf.init (&plan->map, HB_TAG('b','l','w','f'), true);
khmer_plan->pstf.init (&plan->map, HB_TAG('p','s','t','f'), true);
for (unsigned int i = 0; i < ARRAY_LENGTH (khmer_plan->mask_array); i++)
khmer_plan->mask_array[i] = (khmer_features[i].flags & F_GLOBAL) ?
@ -539,35 +529,6 @@ data_destroy_khmer (void *data)
free (data);
}
static khmer_position_t
consonant_position_from_face (const khmer_shape_plan_t *khmer_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. */
hb_codepoint_t glyphs[3] = {virama, consonant, virama};
if (khmer_plan->blwf.would_substitute (glyphs , 2, face) ||
khmer_plan->blwf.would_substitute (glyphs+1, 2, face))
return POS_BELOW_C;
if (khmer_plan->pstf.would_substitute (glyphs , 2, face) ||
khmer_plan->pstf.would_substitute (glyphs+1, 2, face))
return POS_POST_C;
if (khmer_plan->pref.would_substitute (glyphs , 2, face) ||
khmer_plan->pref.would_substitute (glyphs+1, 2, face))
return POS_POST_C;
return POS_BASE_C;
}
enum syllable_type_t {
consonant_syllable,
@ -617,33 +578,6 @@ compare_khmer_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb)
}
static void
update_consonant_positions (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer)
{
const khmer_shape_plan_t *khmer_plan = (const khmer_shape_plan_t *) plan->data;
if (khmer_plan->config->base_pos != BASE_POS_LAST)
return;
hb_codepoint_t virama;
if (khmer_plan->get_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].khmer_position() == POS_BASE_C)
{
hb_codepoint_t consonant = info[i].codepoint;
info[i].khmer_position() = consonant_position_from_face (khmer_plan, consonant, virama, face);
}
}
}
/* Rules from:
* https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx */
@ -710,101 +644,13 @@ initial_reordering_consonant_syllable (const hb_ot_shape_plan_t *plan,
has_reph = true;
}
switch (khmer_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].khmer_position() != POS_BELOW_C &&
(info[i].khmer_position() != POS_POST_C || seen_below))
{
base = i;
break;
}
if (info[i].khmer_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].khmer_category() == OT_ZWJ &&
info[i - 1].khmer_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;
/* The first consonant is always the base. */
base = start;
/* 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].khmer_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].khmer_position() = POS_BELOW_C;
}
break;
case BASE_POS_FIRST:
{
/* The first consonant is always the base. */
assert (khmer_plan->config->reph_mode == REPH_MODE_VIS_REPHA);
assert (!has_reph);
base = start;
/* Mark all subsequent consonants as below. */
for (unsigned int i = base + 1; i < end; i++)
if (is_consonant (info[i]))
info[i].khmer_position() = POS_BELOW_C;
}
break;
}
/* Mark all subsequent consonants as below. */
for (unsigned int i = base + 1; i < end; i++)
if (is_consonant (info[i]))
info[i].khmer_position() = POS_BELOW_C;
/* -> 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
@ -1146,7 +992,6 @@ initial_reordering (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer)
{
update_consonant_positions (plan, font, buffer);
insert_dotted_circles (plan, font, buffer);
foreach_syllable (buffer, start, end)
@ -1579,11 +1424,6 @@ decompose_khmer (const hb_ot_shape_normalize_context_t *c,
{
switch (ab)
{
/* Don't decompose these. */
case 0x0931u : return false; /* DEVANAGARI LETTER RRA */
case 0x0B94u : return false; /* TAMIL LETTER AU */
/*
* Decompose split matras that don't have Unicode decompositions.
*/
@ -1594,58 +1434,6 @@ decompose_khmer (const hb_ot_shape_normalize_context_t *c,
case 0x17C0u : *a = 0x17C1u; *b= 0x17C0u; return true;
case 0x17C4u : *a = 0x17C1u; *b= 0x17C4u; return true;
case 0x17C5u : *a = 0x17C1u; *b= 0x17C5u; return true;
#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:
*
* http://www.microsoft.com/typography/OpenTypeDev/sinhala/intro.htm#shaping
*/
const khmer_shape_plan_t *khmer_plan = (const khmer_shape_plan_t *) c->plan->data;
hb_codepoint_t glyph;
if (hb_options ().uniscribe_bug_compatible ||
(c->font->get_nominal_glyph (ab, &glyph) &&
khmer_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);
@ -1661,9 +1449,6 @@ compose_khmer (const hb_ot_shape_normalize_context_t *c,
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);
}

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