[PATCH 1/5] dwrite: Implement reverse chain contextual substitution (GSUB lookup 8).
Nikolay Sivov
nsivov at codeweavers.com
Tue Jun 2 03:48:49 CDT 2020
Signed-off-by: Nikolay Sivov <nsivov at codeweavers.com>
---
dlls/dwrite/opentype.c | 69 ++++++++++++++++++++++++++++++++++++++++--
1 file changed, 67 insertions(+), 2 deletions(-)
diff --git a/dlls/dwrite/opentype.c b/dlls/dwrite/opentype.c
index 58e1a3941c7..fe25c6b692e 100644
--- a/dlls/dwrite/opentype.c
+++ b/dlls/dwrite/opentype.c
@@ -4661,7 +4661,6 @@ static void opentype_layout_replace_glyph(struct scriptshaping_context *context,
context->u.subst.glyphs[context->cur] = glyph;
opentype_set_subst_glyph_props(context, context->cur);
}
- context->cur++;
}
static BOOL opentype_layout_apply_gsub_single_substitution(struct scriptshaping_context *context, const struct lookup *lookup,
@@ -4707,6 +4706,7 @@ static BOOL opentype_layout_apply_gsub_single_substitution(struct scriptshaping_
}
opentype_layout_replace_glyph(context, glyph);
+ context->cur++;
return TRUE;
}
@@ -4801,6 +4801,7 @@ static BOOL opentype_layout_apply_gsub_mult_substitution(struct scriptshaping_co
{
/* Equivalent of single substitution. */
opentype_layout_replace_glyph(context, GET_BE_WORD(glyphs[0]));
+ context->cur++;
}
else if (glyph_count == 0)
{
@@ -4915,6 +4916,7 @@ static BOOL opentype_layout_apply_gsub_alt_substitution(struct scriptshaping_con
}
opentype_layout_replace_glyph(context, glyph);
+ context->cur++;
return TRUE;
}
@@ -4937,6 +4939,7 @@ static BOOL opentype_layout_apply_ligature(struct scriptshaping_context *context
if (comp_count == 1)
{
opentype_layout_replace_glyph(context, GET_BE_WORD(lig->lig_glyph));
+ context->cur++;
return TRUE;
}
@@ -5476,6 +5479,68 @@ static BOOL opentype_layout_apply_gsub_chain_context_substitution(struct scripts
return ret;
}
+static BOOL opentype_layout_apply_gsub_reverse_chain_context_substitution(struct scriptshaping_context *context,
+ const struct lookup *lookup, unsigned int subtable_offset)
+{
+ const struct dwrite_fonttable *table = &context->table->table;
+ unsigned int offset = subtable_offset;
+ UINT16 glyph, format;
+
+ glyph = context->u.subst.glyphs[context->cur];
+
+ format = table_read_be_word(table, offset);
+ offset += 2;
+
+ if (format == 1)
+ {
+ struct match_context mc = { .context = context, .mask = lookup->mask };
+ unsigned int start_index = 0, end_index = 0, backtrack_count, lookahead_count;
+ unsigned int coverage, coverage_index;
+ const UINT16 *backtrack, *lookahead;
+
+ coverage = table_read_be_word(table, offset);
+ offset += 2;
+
+ coverage_index = opentype_layout_is_glyph_covered(table, subtable_offset + coverage, glyph);
+ if (coverage_index == GLYPH_NOT_COVERED)
+ return FALSE;
+
+ backtrack_count = table_read_be_word(table, offset);
+ offset += 2;
+
+ backtrack = table_read_ensure(table, offset, sizeof(*backtrack) * backtrack_count);
+ offset += sizeof(*backtrack) * backtrack_count;
+
+ lookahead_count = table_read_be_word(table, offset);
+ offset += 2;
+
+ lookahead = table_read_ensure(table, offset, sizeof(*lookahead) * lookahead_count);
+ offset += sizeof(*lookahead) * lookahead_count;
+
+ mc.match_func = opentype_match_coverage_func;
+ mc.backtrack_offset = subtable_offset;
+ mc.lookahead_offset = subtable_offset;
+
+ if (opentype_layout_context_match_backtrack(&mc, backtrack_count, backtrack, &start_index) &&
+ opentype_layout_context_match_lookahead(&mc, lookahead_count, lookahead, 1, &end_index))
+ {
+ unsigned int glyph_count = table_read_be_word(table, offset);
+ if (coverage_index >= glyph_count)
+ return FALSE;
+ offset += 2;
+
+ glyph = table_read_be_word(table, offset + coverage_index * sizeof(glyph));
+ opentype_layout_replace_glyph(context, glyph);
+
+ return TRUE;
+ }
+ }
+ else
+ WARN("Unknown reverse chaining contextual substitution format %u.\n", format);
+
+ return FALSE;
+}
+
static BOOL opentype_layout_apply_gsub_lookup(struct scriptshaping_context *context, const struct lookup *lookup)
{
unsigned int i, lookup_type;
@@ -5515,7 +5580,7 @@ static BOOL opentype_layout_apply_gsub_lookup(struct scriptshaping_context *cont
ret = opentype_layout_apply_gsub_chain_context_substitution(context, lookup, subtable_offset);
break;
case GSUB_LOOKUP_REVERSE_CHAINING_CONTEXTUAL_SUBST:
- WARN("Unimplemented lookup %d.\n", lookup->type);
+ ret = opentype_layout_apply_gsub_reverse_chain_context_substitution(context, lookup, subtable_offset);
break;
case GSUB_LOOKUP_EXTENSION_SUBST:
WARN("Invalid lookup type for extension substitution %#x.\n", lookup_type);
--
2.26.2
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