Rework handling of requiredFeature to solve problem with rlig in arial.ttf from winxp
https://bugzilla.mozilla.org/show_bug.cgi?id=986802
Fixes https://github.com/behdad/harfbuzz/pull/39
API Change:
-hb_ot_layout_language_get_required_feature_index
+hb_ot_layout_language_get_required_feature
New API takes an extra pointer argument. Pass NULL in to get
behavior of previous API.
Reworked by behdad
diff --git a/src/hb-ot-map.cc b/src/hb-ot-map.cc
index bd2d87f..4985eb2 100644
--- a/src/hb-ot-map.cc
+++ b/src/hb-ot-map.cc
@@ -99,6 +99,7 @@
{
feature_info_t *info = feature_infos.push();
if (unlikely (!info)) return;
+ if (unlikely (!tag)) return;
info->tag = tag;
info->seq = feature_infos.len;
info->max_value = value;
@@ -131,9 +132,25 @@
{
m.global_mask = 1;
- for (unsigned int table_index = 0; table_index < 2; table_index++) {
+ unsigned int required_feature_index[2];
+ hb_tag_t required_feature_tag[2];
+ /* We default to applying required feature in stage 0. If the required
+ * feature has a tag that is known to the shaper, we apply required feature
+ * in the stage for that tag.
+ */
+ unsigned int required_feature_stage[2] = {0, 0};
+
+ for (unsigned int table_index = 0; table_index < 2; table_index++)
+ {
m.chosen_script[table_index] = chosen_script[table_index];
m.found_script[table_index] = found_script[table_index];
+
+ hb_ot_layout_language_get_required_feature (face,
+ table_tags[table_index],
+ script_index[table_index],
+ language_index[table_index],
+ &required_feature_index[table_index],
+ &required_feature_tag[table_index]);
}
if (!feature_infos.len)
@@ -166,7 +183,8 @@
/* Allocate bits now */
unsigned int next_bit = 1;
- for (unsigned int i = 0; i < feature_infos.len; i++) {
+ for (unsigned int i = 0; i < feature_infos.len; i++)
+ {
const feature_info_t *info = &feature_infos[i];
unsigned int bits_needed;
@@ -184,12 +202,20 @@
hb_bool_t found = false;
unsigned int feature_index[2];
for (unsigned int table_index = 0; table_index < 2; table_index++)
+ {
+ if (required_feature_tag[table_index] == info->tag)
+ {
+ required_feature_stage[table_index] = info->stage[table_index];
+ found = true;
+ continue;
+ }
found |= hb_ot_layout_language_find_feature (face,
table_tags[table_index],
script_index[table_index],
language_index[table_index],
info->tag,
&feature_index[table_index]);
+ }
if (!found && !(info->flags & F_HAS_FALLBACK))
continue;
@@ -224,23 +250,21 @@
add_gsub_pause (NULL);
add_gpos_pause (NULL);
- for (unsigned int table_index = 0; table_index < 2; table_index++) {
- hb_tag_t table_tag = table_tags[table_index];
-
+ for (unsigned int table_index = 0; table_index < 2; table_index++)
+ {
/* Collect lookup indices for features */
- unsigned int required_feature_index;
- if (hb_ot_layout_language_get_required_feature_index (face,
- table_tag,
- script_index[table_index],
- language_index[table_index],
- &required_feature_index))
- m.add_lookups (face, table_index, required_feature_index, 1, true);
-
unsigned int stage_index = 0;
unsigned int last_num_lookups = 0;
for (unsigned stage = 0; stage < current_stage[table_index]; stage++)
{
+ if (required_feature_index[table_index] != HB_OT_LAYOUT_NO_FEATURE_INDEX &&
+ required_feature_stage[table_index] == stage)
+ m.add_lookups (face, table_index,
+ required_feature_index[table_index],
+ 1 /* mask */,
+ true /* auto_zwj */);
+
for (unsigned i = 0; i < m.features.len; i++)
if (m.features[i].stage[table_index] == stage)
m.add_lookups (face, table_index,
