[GSUB] Merge Ligature and context input matching
Looks better now...
diff --git a/src/hb-ot-layout-gsub-table.hh b/src/hb-ot-layout-gsub-table.hh
index c85df46..ac3e8a9 100644
--- a/src/hb-ot-layout-gsub-table.hh
+++ b/src/hb-ot-layout-gsub-table.hh
@@ -491,66 +491,21 @@
unsigned int count = component.len;
if (unlikely (count < 1)) return TRACE_RETURN (false);
- hb_apply_context_t::mark_skipping_forward_iterator_t skippy_iter (c, c->buffer->idx, count - 1);
- if (skippy_iter.has_no_chance ()) return TRACE_RETURN (false);
+ unsigned int end_offset;
+ bool is_mark_ligature;
+ unsigned int total_component_count;
- /*
- * This is perhaps the trickiest part of OpenType... Remarks:
- *
- * - If all components of the ligature were marks, we call this a mark ligature.
- *
- * - If there is no GDEF, and the ligature is NOT a mark ligature, we categorize
- * it as a ligature glyph.
- *
- * - Ligatures cannot be formed across glyphs attached to different components
- * of previous ligatures. Eg. the sequence is LAM,SHADDA,LAM,FATHA,HEH, and
- * LAM,LAM,HEH form a ligature, leaving SHADDA,FATHA next to eachother.
- * However, it would be wrong to ligate that SHADDA,FATHA sequence.o
- * There is an exception to this: If a ligature tries ligating with marks that
- * belong to it itself, go ahead, assuming that the font designer knows what
- * they are doing (otherwise it can break Indic stuff when a matra wants to
- * ligate with a conjunct...)
- */
-
- bool is_mark_ligature = !!(c->property & HB_OT_LAYOUT_GLYPH_CLASS_MARK);
-
- unsigned int total_component_count = 0;
- total_component_count += get_lig_num_comps (c->buffer->cur());
-
- unsigned int first_lig_id = get_lig_id (c->buffer->cur());
- unsigned int first_lig_comp = get_lig_comp (c->buffer->cur());
-
- for (unsigned int i = 1; i < count; i++)
- {
- unsigned int property;
-
- if (!skippy_iter.next (&property)) return TRACE_RETURN (false);
-
- if (likely (c->buffer->info[skippy_iter.idx].codepoint != component[i])) return TRACE_RETURN (false);
-
- unsigned int this_lig_id = get_lig_id (c->buffer->info[skippy_iter.idx]);
- unsigned int this_lig_comp = get_lig_comp (c->buffer->info[skippy_iter.idx]);
-
- if (first_lig_id && first_lig_comp) {
- /* If first component was attached to a previous ligature component,
- * all subsequent components should be attached to the same ligature
- * component, otherwise we shouldn't ligate them. */
- if (first_lig_id != this_lig_id || first_lig_comp != this_lig_comp)
- return TRACE_RETURN (false);
- } else {
- /* If first component was NOT attached to a previous ligature component,
- * all subsequent components should also NOT be attached to any ligature
- * component, unless they are attached to the first component itself! */
- if (this_lig_id && this_lig_comp && (this_lig_id != first_lig_id))
- return TRACE_RETURN (false);
- }
-
- is_mark_ligature = is_mark_ligature && (property & HB_OT_LAYOUT_GLYPH_CLASS_MARK);
- total_component_count += get_lig_num_comps (c->buffer->info[skippy_iter.idx]);
- }
+ if (likely (!match_input (c, count,
+ &component[1],
+ match_glyph,
+ NULL,
+ &end_offset,
+ &is_mark_ligature,
+ &total_component_count)))
+ return TRACE_RETURN (false);
/* Deal, we are forming the ligature. */
- c->buffer->merge_clusters (c->buffer->idx, skippy_iter.idx + 1);
+ c->buffer->merge_clusters (c->buffer->idx, c->buffer->idx + end_offset);
/*
* - If it *is* a mark ligature, we don't allocate a new ligature id, and leave
diff --git a/src/hb-ot-layout-gsubgpos-private.hh b/src/hb-ot-layout-gsubgpos-private.hh
index 5032d30..3d69736 100644
--- a/src/hb-ot-layout-gsubgpos-private.hh
+++ b/src/hb-ot-layout-gsubgpos-private.hh
@@ -421,13 +421,33 @@
const USHORT input[], /* Array of input values--start with second glyph */
match_func_t match_func,
const void *match_data,
- unsigned int *end_offset = NULL)
+ unsigned int *end_offset = NULL,
+ bool *p_is_mark_ligature = NULL,
+ unsigned int *p_total_component_count = NULL)
{
hb_auto_trace_t<HB_DEBUG_APPLY> trace (&c->debug_depth, "APPLY", NULL, HB_FUNC, "idx %d codepoint %u", c->buffer->idx, c->buffer->cur().codepoint);
hb_apply_context_t::mark_skipping_forward_iterator_t skippy_iter (c, c->buffer->idx, count - 1);
if (skippy_iter.has_no_chance ()) return TRACE_RETURN (false);
+ /*
+ * This is perhaps the trickiest part of OpenType... Remarks:
+ *
+ * - If all components of the ligature were marks, we call this a mark ligature.
+ *
+ * - If there is no GDEF, and the ligature is NOT a mark ligature, we categorize
+ * it as a ligature glyph.
+ *
+ * - Ligatures cannot be formed across glyphs attached to different components
+ * of previous ligatures. Eg. the sequence is LAM,SHADDA,LAM,FATHA,HEH, and
+ * LAM,LAM,HEH form a ligature, leaving SHADDA,FATHA next to eachother.
+ * However, it would be wrong to ligate that SHADDA,FATHA sequence.o
+ * There is an exception to this: If a ligature tries ligating with marks that
+ * belong to it itself, go ahead, assuming that the font designer knows what
+ * they are doing (otherwise it can break Indic stuff when a matra wants to
+ * ligate with a conjunct...)
+ */
+
bool is_mark_ligature = !!(c->property & HB_OT_LAYOUT_GLYPH_CLASS_MARK);
unsigned int total_component_count = 0;
@@ -443,7 +463,6 @@
if (!skippy_iter.next (&property)) return TRACE_RETURN (false);
if (likely (!match_func (c->buffer->info[skippy_iter.idx].codepoint, input[i - 1], match_data))) return false;
-// if (likely (c->buffer->info[skippy_iter.idx].codepoint != component[i])) return TRACE_RETURN (false);
unsigned int this_lig_id = get_lig_id (c->buffer->info[skippy_iter.idx]);
unsigned int this_lig_comp = get_lig_comp (c->buffer->info[skippy_iter.idx]);
@@ -469,6 +488,12 @@
if (end_offset)
*end_offset = skippy_iter.idx - c->buffer->idx + 1;
+ if (p_is_mark_ligature)
+ *p_is_mark_ligature = is_mark_ligature;
+
+ if (p_total_component_count)
+ *p_total_component_count = total_component_count;
+
return true;
}
