[Indic] Apply Indic features
Find the base consonant and apply basic Indic features accordingly.
Nothing complete, but does something for now. Specifically:
no Ra handling right now, and no ZWJ/ZWNJ.
Number of failing shape-complex tests goes from 174 down to 125.
Next: reorder matras.
diff --git a/src/hb-ot-shape-complex-indic-machine.rl b/src/hb-ot-shape-complex-indic-machine.rl
index 640d8cb..53dc20d 100644
--- a/src/hb-ot-shape-complex-indic-machine.rl
+++ b/src/hb-ot-shape-complex-indic-machine.rl
@@ -59,15 +59,17 @@
matra_group = M N? H?;
syllable_tail = SM? (VD VD?)?;
-action found_syllable {
- found_syllable (map, buffer, last, p);
- last = p;
-}
+action found_consonant_syllable { found_consonant_syllable (map, buffer, mask_array, last, p); }
+action found_vowel_syllable { found_vowel_syllable (map, buffer, mask_array, last, p); }
+action found_standalone_cluster { found_standalone_cluster (map, buffer, mask_array, last, p); }
+action found_non_indic { found_non_indic (map, buffer, mask_array, last, p); }
-consonant_syllable = (c.N? (z.H|H.z?))* c.N? A? (H.z? | matra_group*)? syllable_tail %(found_syllable);
-vowel_syllable = (Ra H)? V N? (z.H.c | ZWJ.c)? matra_group* syllable_tail;
-standalone_cluster = (Ra H)? NBSP N? (z? H c)? matra_group* syllable_tail;
-non_indic = X;
+action next_syllable { set_cluster (buffer, p, last); last = p; }
+
+consonant_syllable = (c.N? (z.H|H.z?))* c.N? A? (H.z? | matra_group*)? syllable_tail %(found_consonant_syllable);
+vowel_syllable = (Ra H)? V N? (z.H.c | ZWJ.c)? matra_group* syllable_tail %(found_vowel_syllable);
+standalone_cluster = (Ra H)? NBSP N? (z? H c)? matra_group* syllable_tail %(found_standalone_cluster);
+non_indic = X %(found_non_indic);
syllable =
consonant_syllable
@@ -76,16 +78,25 @@
| non_indic
;
-main := syllable**;
+main := (syllable %(next_syllable))**;
}%%
-#include <stdio.h>
-#include <string.h>
+static void
+set_cluster (hb_buffer_t *buffer,
+ unsigned int start, unsigned int end)
+{
+ unsigned int cluster = buffer->info[start].cluster;
+
+ for (unsigned int i = start + 1; i < end; i++)
+ cluster = MIN (cluster, buffer->info[i].cluster);
+ for (unsigned int i = start; i < end; i++)
+ buffer->info[i].cluster = cluster;
+}
static void
-find_syllables (hb_ot_map_t *map, hb_buffer_t *buffer)
+find_syllables (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array)
{
unsigned int p, pe, eof;
int cs;
diff --git a/src/hb-ot-shape-complex-indic.cc b/src/hb-ot-shape-complex-indic.cc
index e14b894..0579500 100644
--- a/src/hb-ot-shape-complex-indic.cc
+++ b/src/hb-ot-shape-complex-indic.cc
@@ -136,7 +136,7 @@
* and/or
* 2. Probe font lookups to determine consonant positions.
*/
-static const struct {
+static const struct consonant_position_t {
hb_codepoint_t u;
indic_position_t position;
} consonant_positions[] = {
@@ -236,6 +236,28 @@
{0x0D35, POS_POST},
};
+static int
+compare_codepoint (const void *pa, const void *pb)
+{
+ hb_codepoint_t a = * (hb_codepoint_t *) pa;
+ hb_codepoint_t b = * (hb_codepoint_t *) pb;
+
+ return a < b ? -1 : a == b ? 0 : +1;
+}
+
+static indic_position_t
+consonant_position (hb_codepoint_t u)
+{
+ consonant_position_t *record;
+
+ record = (consonant_position_t *) bsearch (&u, consonant_positions,
+ ARRAY_LENGTH (consonant_positions),
+ sizeof (consonant_positions[0]),
+ compare_codepoint);
+
+ return record ? record->position : POS_BASE;
+}
+
static const struct {
hb_tag_t tag;
@@ -281,16 +303,17 @@
HB_TAG('b','l','w','m'),
};
+
+static void
+initial_reordering (const hb_ot_map_t *map,
+ hb_face_t *face,
+ hb_buffer_t *buffer,
+ void *user_data HB_UNUSED);
static void
final_reordering (const hb_ot_map_t *map,
hb_face_t *face,
hb_buffer_t *buffer,
- void *user_data HB_UNUSED)
-{
-
- HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category);
- HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position);
-}
+ void *user_data HB_UNUSED);
void
_hb_ot_shape_complex_collect_features_indic (hb_ot_map_builder_t *map, const hb_segment_properties_t *props)
@@ -300,7 +323,7 @@
* there is a use of it, it's typically at the beginning. */
map->add_bool_feature (HB_TAG('c','c','m','p'));
- map->add_gsub_pause (NULL, NULL);
+ map->add_gsub_pause (initial_reordering, NULL);
for (unsigned int i = 0; i < ARRAY_LENGTH (indic_basic_features); i++)
map->add_bool_feature (indic_basic_features[i].tag, indic_basic_features[i].is_global);
@@ -319,39 +342,185 @@
return TRUE;
}
-static void
-found_syllable (hb_ot_map_t *map, hb_buffer_t *buffer,
- unsigned int start, unsigned int end)
-{
- //fprintf (stderr, "%d %d\n", start, end);
-}
-
-#include "hb-ot-shape-complex-indic-machine.hh"
-
void
_hb_ot_shape_complex_setup_masks_indic (hb_ot_map_t *map, hb_buffer_t *buffer)
{
- unsigned int count = buffer->len;
-
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;
for (unsigned int i = 0; i < count; i++)
{
unsigned int type = get_indic_categories (buffer->info[i].codepoint);
buffer->info[i].indic_category() = type & 0x0F;
buffer->info[i].indic_position() = type >> 4;
+
+ if (buffer->info[i].indic_category() == OT_C)
+ buffer->info[i].indic_position() = consonant_position (buffer->info[i].codepoint);
}
+}
- find_syllables (map, buffer);
+static void
+found_consonant_syllable (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array,
+ unsigned int start, unsigned int end)
+{
+ unsigned int i;
+
+ /* Comments from:
+ * https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx */
+
+ /* 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 = 0;
+
+ /* -> starting from the end of the syllable, move backwards */
+ i = end;
+ do {
+ i--;
+ /* -> until a consonant is found */
+ if (buffer->info[i].indic_category() == OT_C)
+ {
+ /* -> that does not have a below-base or post-base form
+ * (post-base forms have to follow below-base forms), */
+ if (buffer->info[i].indic_position() != POS_BELOW &&
+ buffer->info[i].indic_position() != POS_POST)
+ {
+ base = i;
+ break;
+ }
+
+ /* TODO: or that is not a pre-base reordering Ra, */
+
+ /* -> or arrive at the first consonant. The consonant stopped at will be the base. */
+ base = i;
+ }
+ } while (i > start);
+ if (base < start)
+ base = start; /* Just in case... */
+
+ /* TODO
+ * 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. */
+
+
+ /* 2. Decompose and reorder Matras:
+ *
+ * Each matra and any syllable modifier sign in the cluster are moved to the
+ * appropriate position relative to the consonant(s) in the cluster. 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.
+ */
+
+
+ /* Setup masks now */
+
+ /* Pre-base */
+ for (i = start; i < base; i++)
+ buffer->info[i].mask |= mask_array[HALF] | mask_array[AKHN];
+ /* Base */
+ buffer->info[base].mask |= mask_array[AKHN];
+ /* Post-base */
+ for (i = base + 1; i < end; i++)
+ buffer->info[i].mask |= mask_array[BLWF] | mask_array[PSTF];
+}
+
+
+static void
+found_vowel_syllable (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array,
+ unsigned int start, unsigned int end)
+{
+ /* TODO
+ * Not clear to me how this should work. Do the matras move to before the
+ * independent vowel? No idea.
+ */
+}
+
+static void
+found_standalone_cluster (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array,
+ unsigned int start, unsigned int end)
+{
+ /* TODO
+ * Easiest thing to do here is to convert the NBSP to consonant and
+ * call found_consonant_syllable.
+ */
+}
+
+static void
+found_non_indic (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array,
+ unsigned int start, unsigned int end)
+{
+ /* Nothing to do right now. If we ever switch to using the output
+ * buffer in the reordering process, we'd need to next_glyph() here. */
+}
+
+#include "hb-ot-shape-complex-indic-machine.hh"
+
+static void
+initial_reordering (const hb_ot_map_t *map,
+ hb_face_t *face,
+ hb_buffer_t *buffer,
+ void *user_data HB_UNUSED)
+{
hb_mask_t mask_array[ARRAY_LENGTH (indic_basic_features)] = {0};
unsigned int num_masks = ARRAY_LENGTH (indic_basic_features);
for (unsigned int i = 0; i < num_masks; i++)
mask_array[i] = map->get_1_mask (indic_basic_features[i].tag);
+
+ find_syllables (map, buffer, mask_array);
}
+static void
+final_reordering (const hb_ot_map_t *map,
+ hb_face_t *face,
+ hb_buffer_t *buffer,
+ void *user_data HB_UNUSED)
+{
+ HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category);
+ HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position);
+}
+
+
HB_END_DECLS
