[PATCH 4/5] dwrite: Implement ligature substitution.
Nikolay Sivov
nsivov at codeweavers.com
Thu Jun 11 07:08:59 CDT 2020
Signed-off-by: Nikolay Sivov <nsivov at codeweavers.com>
---
dlls/dwrite/dwrite_private.h | 2 +-
dlls/dwrite/opentype.c | 134 +++++++++++++++++++++++++----------
2 files changed, 97 insertions(+), 39 deletions(-)
diff --git a/dlls/dwrite/dwrite_private.h b/dlls/dwrite/dwrite_private.h
index 4cb35a44e49..661e01123c9 100644
--- a/dlls/dwrite/dwrite_private.h
+++ b/dlls/dwrite/dwrite_private.h
@@ -529,7 +529,7 @@ struct shaping_glyph_properties
UINT16 isZeroWidthSpace : 1;
UINT16 reserved : 1;
UINT16 components : 4;
- UINT16 reserved2 : 4;
+ UINT16 lig_component : 4;
};
struct scriptshaping_context;
diff --git a/dlls/dwrite/opentype.c b/dlls/dwrite/opentype.c
index 63b35155b31..a6e2663ab16 100644
--- a/dlls/dwrite/opentype.c
+++ b/dlls/dwrite/opentype.c
@@ -5104,11 +5104,71 @@ static BOOL opentype_layout_apply_gsub_alt_substitution(struct scriptshaping_con
return TRUE;
}
-static BOOL opentype_layout_apply_ligature(struct scriptshaping_context *context, unsigned int offset)
+static BOOL opentype_layout_context_match_input(const struct match_context *mc, unsigned int count, const UINT16 *input,
+ unsigned int *end_offset, unsigned int *match_positions)
+{
+ struct match_data match_data = { .mc = mc, .subtable_offset = mc->input_offset };
+ struct scriptshaping_context *context = mc->context;
+ struct glyph_iterator iter;
+ unsigned int i;
+
+ if (count > GLYPH_CONTEXT_MAX_LENGTH)
+ return FALSE;
+
+ match_positions[0] = context->cur;
+
+ glyph_iterator_init(context, mc->lookup->flags, context->cur, count - 1, &iter);
+ iter.mask = mc->lookup->mask;
+ iter.match_func = mc->match_func;
+ iter.match_data = &match_data;
+ iter.glyph_data = input;
+
+ for (i = 1; i < count; ++i)
+ {
+ if (!glyph_iterator_next(&iter))
+ return FALSE;
+
+ match_positions[i] = iter.pos;
+ }
+
+ *end_offset = iter.pos - context->cur + 1;
+
+ return TRUE;
+}
+
+static void opentype_layout_unsafe_to_break(struct scriptshaping_context *context, unsigned int idx)
+{
+ if (context->u.buffer.glyph_props[idx].isClusterStart)
+ context->u.buffer.text_props[context->glyph_infos[idx].start_text_idx].canBreakShapingAfter = 0;
+}
+
+static void opentype_layout_delete_glyph(struct scriptshaping_context *context, unsigned int idx)
{
+ unsigned int shift_len;
+
+ shift_len = context->glyph_count - context->cur - 1;
+
+ if (shift_len)
+ {
+ memmove(&context->u.buffer.glyphs[idx], &context->u.buffer.glyphs[idx + 1],
+ shift_len * sizeof(*context->u.buffer.glyphs));
+ memmove(&context->u.buffer.glyph_props[idx], &context->u.buffer.glyph_props[idx + 1],
+ shift_len * sizeof(*context->u.buffer.glyph_props));
+ memmove(&context->glyph_infos[idx], &context->glyph_infos[idx + 1], shift_len * sizeof(*context->glyph_infos));
+ }
+
+ context->glyph_count--;
+}
+
+static BOOL opentype_layout_apply_ligature(struct scriptshaping_context *context, unsigned int offset,
+ const struct lookup *lookup)
+{
+ struct match_context mc = { .context = context, .lookup = lookup, .match_func = opentype_match_glyph_func };
const struct dwrite_fonttable *gsub = &context->table->table;
+ unsigned int match_positions[GLYPH_CONTEXT_MAX_LENGTH];
+ unsigned int i, j, comp_count, match_length = 0;
const struct ot_gsub_lig *lig;
- unsigned int comp_count;
+ UINT16 lig_glyph;
comp_count = table_read_be_word(gsub, offset + FIELD_OFFSET(struct ot_gsub_lig, comp_count));
@@ -5119,16 +5179,46 @@ static BOOL opentype_layout_apply_ligature(struct scriptshaping_context *context
if (!lig)
return FALSE;
+ lig_glyph = GET_BE_WORD(lig->lig_glyph);
+
if (comp_count == 1)
{
- opentype_layout_replace_glyph(context, GET_BE_WORD(lig->lig_glyph));
+ opentype_layout_replace_glyph(context, lig_glyph);
context->cur++;
return TRUE;
}
- /* TODO: actually apply ligature */
+ if (!opentype_layout_context_match_input(&mc, comp_count, lig->components, &match_length, match_positions))
+ return FALSE;
- return FALSE;
+ opentype_layout_replace_glyph(context, lig_glyph);
+ context->u.buffer.glyph_props[context->cur].components = comp_count;
+
+ /* Positioning against a ligature implies keeping track of ligature component
+ glyph should be attached to. Update per-glyph property for interleaving glyphs,
+ 0 means attaching to last component, n - attaching to n-th glyph before last. */
+ for (i = 1; i < comp_count; ++i)
+ {
+ j = match_positions[i - 1] + 1;
+ while (j < match_positions[i])
+ {
+ context->u.buffer.glyph_props[j++].lig_component = comp_count - i;
+ }
+ opentype_layout_unsafe_to_break(context, i);
+ context->u.buffer.glyph_props[i].isClusterStart = 0;
+ context->glyph_infos[i].start_text_idx = 0;
+ }
+
+ /* Delete ligated glyphs, backwards to preserve index. */
+ for (i = 1; i < comp_count; ++i)
+ {
+ opentype_layout_delete_glyph(context, match_positions[comp_count - i]);
+ }
+
+ /* Skip whole matched sequence, accounting for deleted glyphs. */
+ context->cur += match_length - (comp_count - 1);
+
+ return TRUE;
}
static BOOL opentype_layout_apply_gsub_lig_substitution(struct scriptshaping_context *context, const struct lookup *lookup,
@@ -5173,7 +5263,7 @@ static BOOL opentype_layout_apply_gsub_lig_substitution(struct scriptshaping_con
/* First applicable ligature is used. */
for (i = 0; i < lig_count; ++i)
{
- if (opentype_layout_apply_ligature(context, offset + GET_BE_WORD(lig_set->offsets[i])))
+ if (opentype_layout_apply_ligature(context, offset + GET_BE_WORD(lig_set->offsets[i]), lookup))
return TRUE;
}
}
@@ -5183,38 +5273,6 @@ static BOOL opentype_layout_apply_gsub_lig_substitution(struct scriptshaping_con
return FALSE;
}
-static BOOL opentype_layout_context_match_input(const struct match_context *mc, unsigned int count, const UINT16 *input,
- unsigned int *end_offset, unsigned int *match_positions)
-{
- struct match_data match_data = { .mc = mc, .subtable_offset = mc->input_offset };
- struct scriptshaping_context *context = mc->context;
- struct glyph_iterator iter;
- unsigned int i;
-
- if (count > GLYPH_CONTEXT_MAX_LENGTH)
- return FALSE;
-
- match_positions[0] = context->cur;
-
- glyph_iterator_init(context, mc->lookup->flags, context->cur, count - 1, &iter);
- iter.mask = mc->lookup->mask;
- iter.match_func = mc->match_func;
- iter.match_data = &match_data;
- iter.glyph_data = input;
-
- for (i = 1; i < count; ++i)
- {
- if (!glyph_iterator_next(&iter))
- return FALSE;
-
- match_positions[i] = iter.pos;
- }
-
- *end_offset = iter.pos - context->cur + 1;
-
- return TRUE;
-}
-
static BOOL opentype_layout_context_match_backtrack(const struct match_context *mc, unsigned int count,
const UINT16 *backtrack, unsigned int *match_start)
{
--
2.26.2
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