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[hangul] Apply the appropriate *jmo features to decomposed syllables, including Old Hangul sequences that don't have Unicode compositions. Merge clusters in decomposed syllables.

This commit is contained in:
Jonathan Kew 2014-01-20 10:35:07 +00:00
parent 8fc1f7fe74
commit 103436838d
1 changed files with 165 additions and 32 deletions
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185
src/hb-ot-shape-complex-hangul.cc
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@ -30,21 +30,62 @@
/* Hangul shaper */
static const hb_tag_t hangul_features[] =
/* Same order as the feature array below */
enum {
NONE,
LJMO,
VJMO,
TJMO,
FIRST_HANGUL_FEATURE = LJMO,
HANGUL_FEATURE_COUNT = TJMO + 1
};
static const hb_tag_t hangul_features[HANGUL_FEATURE_COUNT] =
{
HB_TAG_NONE,
HB_TAG('l','j','m','o'),
HB_TAG('v','j','m','o'),
HB_TAG('t','j','m','o'),
HB_TAG_NONE
HB_TAG('t','j','m','o')
};
static void
collect_features_hangul (hb_ot_shape_planner_t *plan)
{
for (const hb_tag_t *script_features = hangul_features; script_features && *script_features; script_features++)
plan->map.add_global_bool_feature (*script_features);
hb_ot_map_builder_t *map = &plan->map;
for (unsigned int i = FIRST_HANGUL_FEATURE; i < HANGUL_FEATURE_COUNT; i++)
map->add_feature (hangul_features[i], 1, F_NONE);
}
struct hangul_shape_plan_t
{
ASSERT_POD ();
hb_mask_t mask_array[HANGUL_FEATURE_COUNT];
};
static void *
data_create_hangul (const hb_ot_shape_plan_t *plan)
{
hangul_shape_plan_t *hangul_plan = (hangul_shape_plan_t *) calloc (1, sizeof (hangul_shape_plan_t));
if (unlikely (!hangul_plan))
return NULL;
for (unsigned int i = 0; i < HANGUL_FEATURE_COUNT; i++)
hangul_plan->mask_array[i] = plan->map.get_1_mask (hangul_features[i]);
return hangul_plan;
}
static void
data_destroy_hangul (void *data)
{
free (data);
}
/* Constants for algorithmic hangul syllable [de]composition. */
#define LBase 0x1100
#define VBase 0x1161
#define TBase 0x11A7
@ -60,13 +101,28 @@ collect_features_hangul (hb_ot_shape_planner_t *plan)
#define isCombiningT(u) (hb_in_range<hb_codepoint_t> ((u), TBase+1, TBase+TCount-1))
#define isCombinedS(u) (hb_in_range<hb_codepoint_t> ((u), SBase, SBase+SCount-1))
#define isL(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x1100, 0x115F, 0xA960, 0xA97C))
#define isV(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x1160, 0x11A7, 0xD7B0, 0xD7C6))
#define isT(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x11A8, 0x11FF, 0xD7CB, 0xD7FB))
/* buffer var allocations */
#define hangul_shaping_feature() complex_var_u8_0() /* hangul jamo shaping feature */
static bool
is_zero_width_char (hb_font_t *font,
hb_codepoint_t unicode)
{
hb_codepoint_t glyph;
return hb_font_get_glyph (font, unicode, 0, &glyph) && hb_font_get_glyph_h_advance (font, glyph) == 0;
}
static void
preprocess_text_hangul (const hb_ot_shape_plan_t *plan,
hb_buffer_t *buffer,
hb_font_t *font)
{
HB_BUFFER_ALLOCATE_VAR (buffer, hangul_shaping_feature);
/* Hangul syllables come in two shapes: LV, and LVT. Of those:
*
* - LV can be precomposed, or decomposed. Lets call those
@ -90,7 +146,7 @@ preprocess_text_hangul (const hb_ot_shape_plan_t *plan,
* Here is what we want to accomplish in this shaper:
*
* - If the whole syllable can be precomposed, do that,
* - Otherwise, fully decompose.
* - Otherwise, fully decompose and apply ljmo/vjmo/tjmo features.
*
* That is, of the different possible syllables:
*
@ -113,46 +169,71 @@ preprocess_text_hangul (const hb_ot_shape_plan_t *plan,
*/
buffer->clear_output ();
unsigned int start = 0, end = 0; /* Extent of most recently seen syllable;
* valid only if start < end
*/
unsigned int count = buffer->len;
for (buffer->idx = 0; buffer->idx < count;)
{
hb_codepoint_t u = buffer->cur().codepoint;
if (isCombiningL(u) && buffer->idx + 1 < count)
start = buffer->out_len; /* Remember current position as a potential syllable start;
* will only be used if we set end to a later position.
*/
if (isL (u) && buffer->idx + 1 < count)
{
hb_codepoint_t l = u;
hb_codepoint_t v = buffer->cur(+1).codepoint;
if (isCombiningV(v))
if (isV (v))
{
/* Have <L,V> or <L,V,T>. */
unsigned int len = 2;
hb_codepoint_t t = 0;
unsigned int tindex = 0;
if (buffer->idx + 2 < count)
{
hb_codepoint_t t = buffer->cur(+2).codepoint;
if (isCombiningT(t))
{
len = 3;
tindex = t - TBase;
}
else if (isT (t))
{
/* Old T jamo. Doesn't combine. Don't combine *anything*. */
len = 0;
}
t = buffer->cur(+2).codepoint;
if (isT (t))
tindex = t - TBase; /* Only used if isCombiningT (t); otherwise invalid. */
else
t = 0; /* The next character was not a trailing jamo. */
}
if (len)
/* We've got a syllable <L,V,T?>; see if it can potentially be composed. */
if (isCombiningL (l) && isCombiningV (v) && (t == 0 || isCombiningT (t)))
{
/* Try to compose; if this succeeds, end is set to start+1. */
hb_codepoint_t s = SBase + (l - LBase) * NCount + (v - VBase) * TCount + tindex;
if (font->has_glyph (s))
{
buffer->replace_glyphs (len, 1, &s);
buffer->replace_glyphs (t ? 3 : 2, 1, &s);
if (unlikely (buffer->in_error))
return;
end = start + 1;
continue;
}
}
/* We didn't compose, either because it's an Old Hangul syllable without a
* precomposed character in Unicode, or because the font didn't support the
* necessary precomposed glyph.
* Set jamo features on the individual glyphs, and advance past them.
*/
buffer->cur().hangul_shaping_feature() = LJMO;
buffer->next_glyph ();
buffer->cur().hangul_shaping_feature() = VJMO;
buffer->next_glyph ();
if (t)
{
buffer->cur().hangul_shaping_feature() = TJMO;
buffer->next_glyph ();
end = start + 3;
}
else
end = start + 2;
buffer->merge_out_clusters (start, end);
continue;
}
}
@ -178,6 +259,7 @@ preprocess_text_hangul (const hb_ot_shape_plan_t *plan,
buffer->replace_glyphs (2, 1, &new_s);
if (unlikely (buffer->in_error))
return;
end = start + 1;
continue;
}
}
@ -197,31 +279,82 @@ preprocess_text_hangul (const hb_ot_shape_plan_t *plan,
font->has_glyph (decomposed[1]) &&
(!tindex || font->has_glyph (decomposed[2])))
{
buffer->replace_glyphs (1, tindex ? 3 : 2, decomposed);
unsigned int s_len = tindex ? 3 : 2;
buffer->replace_glyphs (1, s_len, decomposed);
if (unlikely (buffer->in_error))
return;
/* We decomposed S: apply jamo features to the individual glyphs
* that are now in buffer->out_info.
*/
hb_glyph_info_t *info = buffer->out_info;
/* If we decomposed an LV because of a non-combining T following,
* we want to include this T in the syllable.
*/
if (has_glyph && !tindex)
{
buffer->next_glyph ();
s_len++;
}
end = start + s_len;
unsigned int i = start;
info[i++].hangul_shaping_feature() = LJMO;
info[i++].hangul_shaping_feature() = VJMO;
if (i < end)
info[i++].hangul_shaping_feature() = TJMO;
buffer->merge_out_clusters (start, end);
continue;
}
}
if (has_glyph)
{
/* We didn't decompose the S, so just advance past it. */
end = start + 1;
buffer->next_glyph ();
continue;
}
}
/* Didn't find a recognizable syllable. */
buffer->next_glyph ();
}
buffer->swap_buffers ();
}
static void
setup_masks_hangul (const hb_ot_shape_plan_t *plan,
hb_buffer_t *buffer,
hb_font_t *font HB_UNUSED)
{
const hangul_shape_plan_t *hangul_plan = (const hangul_shape_plan_t *) plan->data;
if (likely (hangul_plan))
{
unsigned int count = buffer->len;
hb_glyph_info_t *info = buffer->info;
for (unsigned int i = 0; i < count; i++, info++)
info->mask |= hangul_plan->mask_array[info->hangul_shaping_feature()];
}
HB_BUFFER_DEALLOCATE_VAR (buffer, hangul_shaping_feature);
}
const hb_ot_complex_shaper_t _hb_ot_complex_shaper_hangul =
{
"hangul",
collect_features_hangul,
NULL, /* override_features */
NULL, /* data_create */
NULL, /* data_destroy */
data_create_hangul, /* data_create */
data_destroy_hangul, /* data_destroy */
preprocess_text_hangul,
HB_OT_SHAPE_NORMALIZATION_MODE_NONE,
NULL, /* decompose */
NULL, /* compose */
NULL, /* setup_masks */
setup_masks_hangul, /* setup_masks */
HB_OT_SHAPE_ZERO_WIDTH_MARKS_DEFAULT,
false, /* fallback_position */
};