[GSUB] Merge Ligature and context input matching
Looks better now...
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commit
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4
TODO
4
TODO
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@ -1,10 +1,6 @@
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General fixes:
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General fixes:
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=============
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=============
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- Ligature matching and match_input() of (Chain)Context should use the
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same logic. Right now the Ligature logic is more involved. Possibly
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merge, or duplicate.
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- mask propagation? (when ligation, "or" the masks).
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- mask propagation? (when ligation, "or" the masks).
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- Warn at compile time (and runtime with HB_DEBUG?) if no Unicode / font
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- Warn at compile time (and runtime with HB_DEBUG?) if no Unicode / font
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@ -491,66 +491,21 @@ struct Ligature
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unsigned int count = component.len;
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unsigned int count = component.len;
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if (unlikely (count < 1)) return TRACE_RETURN (false);
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if (unlikely (count < 1)) return TRACE_RETURN (false);
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hb_apply_context_t::mark_skipping_forward_iterator_t skippy_iter (c, c->buffer->idx, count - 1);
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unsigned int end_offset;
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if (skippy_iter.has_no_chance ()) return TRACE_RETURN (false);
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bool is_mark_ligature;
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unsigned int total_component_count;
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/*
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if (likely (!match_input (c, count,
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* This is perhaps the trickiest part of OpenType... Remarks:
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&component[1],
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*
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match_glyph,
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* - If all components of the ligature were marks, we call this a mark ligature.
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NULL,
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*
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&end_offset,
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* - If there is no GDEF, and the ligature is NOT a mark ligature, we categorize
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&is_mark_ligature,
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* it as a ligature glyph.
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&total_component_count)))
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*
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* - Ligatures cannot be formed across glyphs attached to different components
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* of previous ligatures. Eg. the sequence is LAM,SHADDA,LAM,FATHA,HEH, and
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* LAM,LAM,HEH form a ligature, leaving SHADDA,FATHA next to eachother.
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* However, it would be wrong to ligate that SHADDA,FATHA sequence.o
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* There is an exception to this: If a ligature tries ligating with marks that
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* belong to it itself, go ahead, assuming that the font designer knows what
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* they are doing (otherwise it can break Indic stuff when a matra wants to
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* ligate with a conjunct...)
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*/
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bool is_mark_ligature = !!(c->property & HB_OT_LAYOUT_GLYPH_CLASS_MARK);
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unsigned int total_component_count = 0;
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total_component_count += get_lig_num_comps (c->buffer->cur());
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unsigned int first_lig_id = get_lig_id (c->buffer->cur());
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unsigned int first_lig_comp = get_lig_comp (c->buffer->cur());
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for (unsigned int i = 1; i < count; i++)
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{
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unsigned int property;
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if (!skippy_iter.next (&property)) return TRACE_RETURN (false);
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if (likely (c->buffer->info[skippy_iter.idx].codepoint != component[i])) return TRACE_RETURN (false);
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unsigned int this_lig_id = get_lig_id (c->buffer->info[skippy_iter.idx]);
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unsigned int this_lig_comp = get_lig_comp (c->buffer->info[skippy_iter.idx]);
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if (first_lig_id && first_lig_comp) {
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/* If first component was attached to a previous ligature component,
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* all subsequent components should be attached to the same ligature
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* component, otherwise we shouldn't ligate them. */
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if (first_lig_id != this_lig_id || first_lig_comp != this_lig_comp)
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return TRACE_RETURN (false);
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return TRACE_RETURN (false);
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} else {
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/* If first component was NOT attached to a previous ligature component,
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* all subsequent components should also NOT be attached to any ligature
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* component, unless they are attached to the first component itself! */
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if (this_lig_id && this_lig_comp && (this_lig_id != first_lig_id))
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return TRACE_RETURN (false);
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}
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is_mark_ligature = is_mark_ligature && (property & HB_OT_LAYOUT_GLYPH_CLASS_MARK);
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total_component_count += get_lig_num_comps (c->buffer->info[skippy_iter.idx]);
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}
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/* Deal, we are forming the ligature. */
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/* Deal, we are forming the ligature. */
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c->buffer->merge_clusters (c->buffer->idx, skippy_iter.idx + 1);
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c->buffer->merge_clusters (c->buffer->idx, c->buffer->idx + end_offset);
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/*
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/*
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* - If it *is* a mark ligature, we don't allocate a new ligature id, and leave
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* - If it *is* a mark ligature, we don't allocate a new ligature id, and leave
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@ -421,13 +421,33 @@ static inline bool match_input (hb_apply_context_t *c,
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const USHORT input[], /* Array of input values--start with second glyph */
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const USHORT input[], /* Array of input values--start with second glyph */
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match_func_t match_func,
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match_func_t match_func,
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const void *match_data,
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const void *match_data,
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unsigned int *end_offset = NULL)
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unsigned int *end_offset = NULL,
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bool *p_is_mark_ligature = NULL,
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unsigned int *p_total_component_count = NULL)
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{
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{
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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);
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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);
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hb_apply_context_t::mark_skipping_forward_iterator_t skippy_iter (c, c->buffer->idx, count - 1);
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hb_apply_context_t::mark_skipping_forward_iterator_t skippy_iter (c, c->buffer->idx, count - 1);
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if (skippy_iter.has_no_chance ()) return TRACE_RETURN (false);
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if (skippy_iter.has_no_chance ()) return TRACE_RETURN (false);
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/*
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* This is perhaps the trickiest part of OpenType... Remarks:
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*
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* - If all components of the ligature were marks, we call this a mark ligature.
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*
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* - If there is no GDEF, and the ligature is NOT a mark ligature, we categorize
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* it as a ligature glyph.
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*
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* - Ligatures cannot be formed across glyphs attached to different components
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* of previous ligatures. Eg. the sequence is LAM,SHADDA,LAM,FATHA,HEH, and
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* LAM,LAM,HEH form a ligature, leaving SHADDA,FATHA next to eachother.
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* However, it would be wrong to ligate that SHADDA,FATHA sequence.o
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* There is an exception to this: If a ligature tries ligating with marks that
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* belong to it itself, go ahead, assuming that the font designer knows what
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* they are doing (otherwise it can break Indic stuff when a matra wants to
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* ligate with a conjunct...)
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*/
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bool is_mark_ligature = !!(c->property & HB_OT_LAYOUT_GLYPH_CLASS_MARK);
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bool is_mark_ligature = !!(c->property & HB_OT_LAYOUT_GLYPH_CLASS_MARK);
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unsigned int total_component_count = 0;
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unsigned int total_component_count = 0;
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@ -443,7 +463,6 @@ static inline bool match_input (hb_apply_context_t *c,
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if (!skippy_iter.next (&property)) return TRACE_RETURN (false);
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if (!skippy_iter.next (&property)) return TRACE_RETURN (false);
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if (likely (!match_func (c->buffer->info[skippy_iter.idx].codepoint, input[i - 1], match_data))) return false;
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if (likely (!match_func (c->buffer->info[skippy_iter.idx].codepoint, input[i - 1], match_data))) return false;
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// if (likely (c->buffer->info[skippy_iter.idx].codepoint != component[i])) return TRACE_RETURN (false);
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unsigned int this_lig_id = get_lig_id (c->buffer->info[skippy_iter.idx]);
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unsigned int this_lig_id = get_lig_id (c->buffer->info[skippy_iter.idx]);
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unsigned int this_lig_comp = get_lig_comp (c->buffer->info[skippy_iter.idx]);
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unsigned int this_lig_comp = get_lig_comp (c->buffer->info[skippy_iter.idx]);
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@ -469,6 +488,12 @@ static inline bool match_input (hb_apply_context_t *c,
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if (end_offset)
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if (end_offset)
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*end_offset = skippy_iter.idx - c->buffer->idx + 1;
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*end_offset = skippy_iter.idx - c->buffer->idx + 1;
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if (p_is_mark_ligature)
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*p_is_mark_ligature = is_mark_ligature;
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if (p_total_component_count)
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*p_total_component_count = total_component_count;
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return true;
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return true;
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}
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}
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