[GSUB] Implement Alternate subtables
This commit is contained in:
Behdad Esfahbod
parent
4f27ce7e02
commit
52886ca56b
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@ -221,10 +221,12 @@ struct MultipleSubstFormat1 {
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glyph_id = IN_CURGLYPH ();
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index = get_glyph_coverage (glyph_id);
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if (index >= sequenceCount)
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return false;
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const Sequence &seq = (*this)[index];
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if (HB_UNLIKELY (!seq.get_len ()))
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return false;
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_hb_buffer_add_output_glyph_ids (buffer, 1,
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seq.glyphCount, seq.substitute,
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0xFFFF, 0xFFFF);
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@ -285,7 +287,9 @@ DEFINE_NULL (MultipleSubst, 2);
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struct AlternateSet {
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/* TODO */
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/* GlyphIDs, in no particular order */
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DEFINE_ARRAY_TYPE (GlyphID, alternate, glyphCount);
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private:
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USHORT glyphCount; /* Number of GlyphIDs in the Alternate
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@ -296,7 +300,62 @@ struct AlternateSet {
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DEFINE_NULL_ASSERT_SIZE (AlternateSet, 2);
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struct AlternateSubstFormat1 {
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/* TODO */
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friend struct AlternateSubst;
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private:
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/* AlternateSet tables, in Coverage Index order */
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DEFINE_OFFSET_ARRAY_TYPE (AlternateSet, alternateSet, alternateSetCount);
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DEFINE_GET_ACCESSOR (Coverage, coverage, coverage);
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DEFINE_GET_GLYPH_COVERAGE (glyph_coverage);
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inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const {
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hb_codepoint_t glyph_id;
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unsigned int index;
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unsigned int property;
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HB_UNUSED (nesting_level_left);
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if (HB_UNLIKELY (context_length < 1))
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return false;
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if (!_hb_ot_layout_check_glyph_property (layout, IN_CURITEM (), lookup_flag, &property))
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return false;
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glyph_id = IN_CURGLYPH ();
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index = get_glyph_coverage (glyph_id);
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const AlternateSet &alt_set = (*this)[index];
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if (HB_UNLIKELY (!alt_set.get_len ()))
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return false;
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unsigned int alt_index = 0;
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/* XXX callback to user to choose alternate
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if ( gsub->altfunc )
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alt_index = (gsub->altfunc)( buffer->out_pos, glyph_id,
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aset.GlyphCount, aset.Alternate,
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gsub->data );
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*/
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if (HB_UNLIKELY (alt_index >= alt_set.get_len ()))
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return false;
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glyph_id = alt_set[alt_index];
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_hb_buffer_replace_output_glyph (buffer, glyph_id, context_length == NO_CONTEXT);
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if ( _hb_ot_layout_has_new_glyph_classes (layout) )
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{
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/* we inherit the old glyph class to the substituted glyph */
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_hb_ot_layout_set_glyph_property (layout, glyph_id, property);
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}
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return true;
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}
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private:
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USHORT substFormat; /* Format identifier--format = 1 */
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@ -310,6 +369,34 @@ struct AlternateSubstFormat1 {
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};
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ASSERT_SIZE (AlternateSubstFormat1, 6);
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struct AlternateSubst {
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friend struct SubstLookupSubTable;
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private:
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unsigned int get_size (void) const {
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switch (u.substFormat) {
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case 1: return sizeof (u.format1);
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default:return sizeof (u.substFormat);
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}
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}
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inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const {
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switch (u.substFormat) {
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case 1: return u.format1.substitute (SUBTABLE_SUBSTITUTE_ARGS);
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default:return false;
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}
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}
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private:
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union {
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USHORT substFormat; /* Format identifier */
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AlternateSubstFormat1 format1;
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} u;
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};
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DEFINE_NULL (AlternateSubst, 2);
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struct Ligature {
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/* TODO */
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@ -716,9 +803,9 @@ struct SubstLookupSubTable {
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unsigned int get_size (unsigned int lookup_type) const {
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switch (lookup_type) {
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case GSUB_Single: return u.single.get_size ();
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case GSUB_Multiple: return u.multiple.get_size ();
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/*
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case GSUB_Alternate:
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case GSUB_Multiple: return u.multiple.get_size ();
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case GSUB_Alternate: return u.alternate.get_size ();
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/*
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case GSUB_Ligature:
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case GSUB_Context:
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case GSUB_ChainingContext:
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@ -736,8 +823,8 @@ struct SubstLookupSubTable {
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switch (lookup_type) {
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case GSUB_Single: return u.single.substitute (SUBTABLE_SUBSTITUTE_ARGS);
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case GSUB_Multiple: return u.multiple.substitute (SUBTABLE_SUBSTITUTE_ARGS);
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case GSUB_Alternate: return u.alternate.substitute (SUBTABLE_SUBSTITUTE_ARGS);
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/*
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case GSUB_Alternate:
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case GSUB_Ligature:
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case GSUB_Context:
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case GSUB_ChainingContext:
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@ -755,6 +842,7 @@ struct SubstLookupSubTable {
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USHORT substFormat;
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SingleSubst single;
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MultipleSubst multiple;
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AlternateSubst alternate;
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ExtensionSubst extension;
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} u;
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@ -822,7 +822,7 @@ struct ClassDefFormat1 {
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friend struct ClassDef;
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private:
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/* GlyphIDs, in sorted numerical order */
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/* Class Values, in sorted numerical order */
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DEFINE_ARRAY_TYPE (USHORT, classValueArray, glyphCount);
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inline hb_ot_layout_class_t get_class (hb_codepoint_t glyph_id) const {
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