[ot] Search globally for 'vert' feature if not found in specified script/lang
Fixes https://github.com/behdad/harfbuzz/issues/63
diff --git a/src/hb-ot-layout-private.hh b/src/hb-ot-layout-private.hh
index d854563..a98734a 100644
--- a/src/hb-ot-layout-private.hh
+++ b/src/hb-ot-layout-private.hh
@@ -36,6 +36,15 @@
#include "hb-set-private.hh"
+/* Private API corresponding to hb-ot-layout.h: */
+
+HB_INTERNAL hb_bool_t
+hb_ot_layout_table_find_feature (hb_face_t *face,
+ hb_tag_t table_tag,
+ hb_tag_t feature_tag,
+ unsigned int *feature_index);
+
+
/*
* GDEF
*/
diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc
index 5570a81..6fe7b6c 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -291,6 +291,28 @@
return g.get_feature_tags (start_offset, feature_count, feature_tags);
}
+hb_bool_t
+hb_ot_layout_table_find_feature (hb_face_t *face,
+ hb_tag_t table_tag,
+ hb_tag_t feature_tag,
+ unsigned int *feature_index)
+{
+ ASSERT_STATIC (OT::Index::NOT_FOUND_INDEX == HB_OT_LAYOUT_NO_FEATURE_INDEX);
+ const OT::GSUBGPOS &g = get_gsubgpos_table (face, table_tag);
+
+ unsigned int num_features = g.get_feature_count ();
+ for (unsigned int i = 0; i < num_features; i++)
+ {
+ if (feature_tag == g.get_feature_tag (i)) {
+ if (feature_index) *feature_index = i;
+ return true;
+ }
+ }
+
+ if (feature_index) *feature_index = HB_OT_LAYOUT_NO_FEATURE_INDEX;
+ return false;
+}
+
unsigned int
hb_ot_layout_script_get_language_tags (hb_face_t *face,
diff --git a/src/hb-ot-map-private.hh b/src/hb-ot-map-private.hh
index 86b7e9f..f9538af 100644
--- a/src/hb-ot-map-private.hh
+++ b/src/hb-ot-map-private.hh
@@ -154,9 +154,10 @@
enum hb_ot_map_feature_flags_t {
F_NONE = 0x0000u,
- F_GLOBAL = 0x0001u,
- F_HAS_FALLBACK = 0x0002u,
- F_MANUAL_ZWJ = 0x0004u
+ F_GLOBAL = 0x0001u, /* Feature applies to all characters; results in no mask allocated for it. */
+ F_HAS_FALLBACK = 0x0002u, /* Has fallback implementation, so include mask bit even if feature not found. */
+ F_MANUAL_ZWJ = 0x0004u, /* Don't skip over ZWJ when matching. */
+ F_GLOBAL_SEARCH = 0x0008u /* If feature not found in LangSys, look for it in global feature list and pick one. */
};
/* Macro version for where const is desired. */
#define F_COMBINE(l,r) (hb_ot_map_feature_flags_t ((unsigned int) (l) | (unsigned int) (r)))
diff --git a/src/hb-ot-map.cc b/src/hb-ot-map.cc
index 4985eb2..95bd04e 100644
--- a/src/hb-ot-map.cc
+++ b/src/hb-ot-map.cc
@@ -216,6 +216,16 @@
info->tag,
&feature_index[table_index]);
}
+ if (!found && (info->flags & F_GLOBAL_SEARCH))
+ {
+ for (unsigned int table_index = 0; table_index < 2; table_index++)
+ {
+ found |= hb_ot_layout_table_find_feature (face,
+ table_tags[table_index],
+ info->tag,
+ &feature_index[table_index]);
+ }
+ }
if (!found && !(info->flags & F_HAS_FALLBACK))
continue;
diff --git a/src/hb-ot-shape.cc b/src/hb-ot-shape.cc
index 00a2121..f20be2a 100644
--- a/src/hb-ot-shape.cc
+++ b/src/hb-ot-shape.cc
@@ -102,7 +102,11 @@
F_HAS_FALLBACK : F_NONE));
else
{
- map->add_global_bool_feature (HB_TAG('v','e','r','t'));
+ /* We really want to find a 'vert' feature if there's any in the font, no
+ * matter which script/langsys it is listed (or not) under.
+ * See various bugs referenced from:
+ * https://github.com/behdad/harfbuzz/issues/63 */
+ map->add_feature (HB_TAG ('v','e','r','t'), 1, F_GLOBAL | F_GLOBAL_SEARCH);
}
if (planner->shaper->override_features)
