[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
parent
8fc1f7fe74
commit
103436838d
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@ -30,21 +30,62 @@
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/* Hangul shaper */
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static const hb_tag_t hangul_features[] =
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/* Same order as the feature array below */
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enum {
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NONE,
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LJMO,
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VJMO,
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TJMO,
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FIRST_HANGUL_FEATURE = LJMO,
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HANGUL_FEATURE_COUNT = TJMO + 1
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};
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static const hb_tag_t hangul_features[HANGUL_FEATURE_COUNT] =
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{
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HB_TAG_NONE,
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HB_TAG('l','j','m','o'),
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HB_TAG('v','j','m','o'),
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HB_TAG('t','j','m','o'),
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HB_TAG_NONE
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HB_TAG('t','j','m','o')
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};
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static void
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collect_features_hangul (hb_ot_shape_planner_t *plan)
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{
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for (const hb_tag_t *script_features = hangul_features; script_features && *script_features; script_features++)
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plan->map.add_global_bool_feature (*script_features);
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hb_ot_map_builder_t *map = &plan->map;
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for (unsigned int i = FIRST_HANGUL_FEATURE; i < HANGUL_FEATURE_COUNT; i++)
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map->add_feature (hangul_features[i], 1, F_NONE);
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}
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struct hangul_shape_plan_t
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{
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ASSERT_POD ();
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hb_mask_t mask_array[HANGUL_FEATURE_COUNT];
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};
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static void *
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data_create_hangul (const hb_ot_shape_plan_t *plan)
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{
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hangul_shape_plan_t *hangul_plan = (hangul_shape_plan_t *) calloc (1, sizeof (hangul_shape_plan_t));
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if (unlikely (!hangul_plan))
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return NULL;
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for (unsigned int i = 0; i < HANGUL_FEATURE_COUNT; i++)
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hangul_plan->mask_array[i] = plan->map.get_1_mask (hangul_features[i]);
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return hangul_plan;
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}
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static void
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data_destroy_hangul (void *data)
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{
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free (data);
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}
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/* Constants for algorithmic hangul syllable [de]composition. */
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#define LBase 0x1100
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#define VBase 0x1161
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#define TBase 0x11A7
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@ -60,13 +101,28 @@ collect_features_hangul (hb_ot_shape_planner_t *plan)
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#define isCombiningT(u) (hb_in_range<hb_codepoint_t> ((u), TBase+1, TBase+TCount-1))
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#define isCombinedS(u) (hb_in_range<hb_codepoint_t> ((u), SBase, SBase+SCount-1))
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#define isT(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x11A8, 0x11FF, 0xD7CB, 0xD7FB))
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#define isL(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x1100, 0x115F, 0xA960, 0xA97C))
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#define isV(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x1160, 0x11A7, 0xD7B0, 0xD7C6))
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#define isT(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x11A8, 0x11FF, 0xD7CB, 0xD7FB))
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/* buffer var allocations */
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#define hangul_shaping_feature() complex_var_u8_0() /* hangul jamo shaping feature */
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static bool
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is_zero_width_char (hb_font_t *font,
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hb_codepoint_t unicode)
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{
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hb_codepoint_t glyph;
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return hb_font_get_glyph (font, unicode, 0, &glyph) && hb_font_get_glyph_h_advance (font, glyph) == 0;
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}
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static void
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preprocess_text_hangul (const hb_ot_shape_plan_t *plan,
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hb_buffer_t *buffer,
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hb_font_t *font)
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{
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HB_BUFFER_ALLOCATE_VAR (buffer, hangul_shaping_feature);
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/* Hangul syllables come in two shapes: LV, and LVT. Of those:
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*
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* - LV can be precomposed, or decomposed. Lets call those
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@ -90,7 +146,7 @@ preprocess_text_hangul (const hb_ot_shape_plan_t *plan,
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* Here is what we want to accomplish in this shaper:
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*
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* - If the whole syllable can be precomposed, do that,
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* - Otherwise, fully decompose.
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* - Otherwise, fully decompose and apply ljmo/vjmo/tjmo features.
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*
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* That is, of the different possible syllables:
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*
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@ -113,52 +169,77 @@ preprocess_text_hangul (const hb_ot_shape_plan_t *plan,
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*/
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buffer->clear_output ();
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unsigned int start = 0, end = 0; /* Extent of most recently seen syllable;
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* valid only if start < end
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*/
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unsigned int count = buffer->len;
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for (buffer->idx = 0; buffer->idx < count;)
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{
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hb_codepoint_t u = buffer->cur().codepoint;
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if (isCombiningL(u) && buffer->idx + 1 < count)
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start = buffer->out_len; /* Remember current position as a potential syllable start;
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* will only be used if we set end to a later position.
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*/
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if (isL (u) && buffer->idx + 1 < count)
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{
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hb_codepoint_t l = u;
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hb_codepoint_t v = buffer->cur(+1).codepoint;
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if (isCombiningV(v))
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if (isV (v))
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{
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/* Have <L,V> or <L,V,T>. */
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unsigned int len = 2;
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/* Have <L,V> or <L,V,T>. */
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hb_codepoint_t t = 0;
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unsigned int tindex = 0;
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if (buffer->idx + 2 < count)
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{
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hb_codepoint_t t = buffer->cur(+2).codepoint;
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if (isCombiningT(t))
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{
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len = 3;
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tindex = t - TBase;
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}
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else if (isT (t))
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{
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/* Old T jamo. Doesn't combine. Don't combine *anything*. */
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len = 0;
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}
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t = buffer->cur(+2).codepoint;
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if (isT (t))
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tindex = t - TBase; /* Only used if isCombiningT (t); otherwise invalid. */
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else
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t = 0; /* The next character was not a trailing jamo. */
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}
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if (len)
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/* We've got a syllable <L,V,T?>; see if it can potentially be composed. */
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if (isCombiningL (l) && isCombiningV (v) && (t == 0 || isCombiningT (t)))
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{
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/* Try to compose; if this succeeds, end is set to start+1. */
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hb_codepoint_t s = SBase + (l - LBase) * NCount + (v - VBase) * TCount + tindex;
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if (font->has_glyph (s))
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{
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buffer->replace_glyphs (len, 1, &s);
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buffer->replace_glyphs (t ? 3 : 2, 1, &s);
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if (unlikely (buffer->in_error))
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return;
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end = start + 1;
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continue;
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}
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}
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/* We didn't compose, either because it's an Old Hangul syllable without a
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* precomposed character in Unicode, or because the font didn't support the
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* necessary precomposed glyph.
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* Set jamo features on the individual glyphs, and advance past them.
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*/
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buffer->cur().hangul_shaping_feature() = LJMO;
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buffer->next_glyph ();
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buffer->cur().hangul_shaping_feature() = VJMO;
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buffer->next_glyph ();
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if (t)
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{
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buffer->cur().hangul_shaping_feature() = TJMO;
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buffer->next_glyph ();
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end = start + 3;
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}
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else
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end = start + 2;
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buffer->merge_out_clusters (start, end);
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continue;
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}
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}
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else if (isCombinedS(u))
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else if (isCombinedS (u))
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{
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/* Have <LV>, <LVT>, or <LV,T> */
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/* Have <LV>, <LVT>, or <LV,T> */
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hb_codepoint_t s = u;
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bool has_glyph = font->has_glyph (s);
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unsigned int lindex = (s - SBase) / NCount;
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@ -173,11 +254,12 @@ preprocess_text_hangul (const hb_ot_shape_plan_t *plan,
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/* <LV,T>, try to combine. */
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unsigned int new_tindex = buffer->cur(+1).codepoint - TBase;
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hb_codepoint_t new_s = s + new_tindex;
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if (font->has_glyph (new_s))
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if (font->has_glyph (new_s))
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{
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buffer->replace_glyphs (2, 1, &new_s);
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if (unlikely (buffer->in_error))
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return;
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end = start + 1;
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continue;
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}
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}
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@ -193,35 +275,86 @@ preprocess_text_hangul (const hb_ot_shape_plan_t *plan,
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hb_codepoint_t decomposed[3] = {LBase + lindex,
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VBase + vindex,
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TBase + tindex};
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if (font->has_glyph (decomposed[0]) &&
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if (font->has_glyph (decomposed[0]) &&
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font->has_glyph (decomposed[1]) &&
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(!tindex || font->has_glyph (decomposed[2])))
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{
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buffer->replace_glyphs (1, tindex ? 3 : 2, decomposed);
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unsigned int s_len = tindex ? 3 : 2;
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buffer->replace_glyphs (1, s_len, decomposed);
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if (unlikely (buffer->in_error))
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return;
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/* We decomposed S: apply jamo features to the individual glyphs
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* that are now in buffer->out_info.
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*/
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hb_glyph_info_t *info = buffer->out_info;
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/* If we decomposed an LV because of a non-combining T following,
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* we want to include this T in the syllable.
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*/
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if (has_glyph && !tindex)
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{
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buffer->next_glyph ();
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s_len++;
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}
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end = start + s_len;
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unsigned int i = start;
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info[i++].hangul_shaping_feature() = LJMO;
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info[i++].hangul_shaping_feature() = VJMO;
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if (i < end)
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info[i++].hangul_shaping_feature() = TJMO;
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buffer->merge_out_clusters (start, end);
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continue;
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}
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}
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if (has_glyph)
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{
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/* We didn't decompose the S, so just advance past it. */
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end = start + 1;
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buffer->next_glyph ();
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continue;
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}
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}
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/* Didn't find a recognizable syllable. */
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buffer->next_glyph ();
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}
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buffer->swap_buffers ();
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}
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static void
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setup_masks_hangul (const hb_ot_shape_plan_t *plan,
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hb_buffer_t *buffer,
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hb_font_t *font HB_UNUSED)
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{
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const hangul_shape_plan_t *hangul_plan = (const hangul_shape_plan_t *) plan->data;
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if (likely (hangul_plan))
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{
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unsigned int count = buffer->len;
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hb_glyph_info_t *info = buffer->info;
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for (unsigned int i = 0; i < count; i++, info++)
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info->mask |= hangul_plan->mask_array[info->hangul_shaping_feature()];
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}
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HB_BUFFER_DEALLOCATE_VAR (buffer, hangul_shaping_feature);
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}
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const hb_ot_complex_shaper_t _hb_ot_complex_shaper_hangul =
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{
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"hangul",
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collect_features_hangul,
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NULL, /* override_features */
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NULL, /* data_create */
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NULL, /* data_destroy */
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data_create_hangul, /* data_create */
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data_destroy_hangul, /* data_destroy */
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preprocess_text_hangul,
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HB_OT_SHAPE_NORMALIZATION_MODE_NONE,
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NULL, /* decompose */
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NULL, /* compose */
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NULL, /* setup_masks */
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setup_masks_hangul, /* setup_masks */
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HB_OT_SHAPE_ZERO_WIDTH_MARKS_DEFAULT,
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false, /* fallback_position */
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};
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