Enable applying GSUB/GPOS features in multiple segments
Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=644184
among others.
Shapers now can request segmented feature application by calling
add_gsub_pause() or add_gpos_pause(). They can also provide a
callback to be called at the pause. Currently the Arabic shaper
uses pauses to enforce certain feature application. The Indic
shaper can use the same facility to pause and do reordering in the
callback.
diff --git a/src/hb-ot-map-private.hh b/src/hb-ot-map-private.hh
index 3ea43a0..9a44bd5 100644
--- a/src/hb-ot-map-private.hh
+++ b/src/hb-ot-map-private.hh
@@ -44,6 +44,9 @@
public:
+ typedef void (*gsub_pause_func_t) (const hb_ot_map_t *map, hb_face_t *face, hb_buffer_t *buffer, void *user_data);
+ typedef void (*gpos_pause_func_t) (const hb_ot_map_t *map, hb_font_t *font, hb_buffer_t *buffer, void *user_data);
+
inline hb_mask_t get_global_mask (void) const { return global_mask; }
inline hb_mask_t get_mask (hb_tag_t tag, unsigned int *shift = NULL) const {
@@ -57,27 +60,23 @@
return map ? map->_1_mask : 0;
}
- inline void substitute (hb_face_t *face, hb_buffer_t *buffer) const {
- for (unsigned int i = 0; i < lookups[0].len; i++)
- hb_ot_layout_substitute_lookup (face, buffer, lookups[0][i].index, lookups[0][i].mask);
- }
-
- inline void position (hb_font_t *font, hb_buffer_t *buffer) const {
- for (unsigned int i = 0; i < lookups[1].len; i++)
- hb_ot_layout_position_lookup (font, buffer, lookups[1][i].index, lookups[1][i].mask);
- }
+ HB_INTERNAL void substitute (hb_face_t *face, hb_buffer_t *buffer) const;
+ HB_INTERNAL void position (hb_font_t *font, hb_buffer_t *buffer) const;
inline void finish (void) {
features.finish ();
lookups[0].finish ();
lookups[1].finish ();
+ pauses[0].finish ();
+ pauses[1].finish ();
}
private:
struct feature_map_t {
hb_tag_t tag; /* should be first for our bsearch to work */
- unsigned int index[2]; /* GSUB, GPOS */
+ unsigned int index[2]; /* GSUB/GPOS */
+ unsigned int stage[2]; /* GSUB/GPOS */
unsigned int shift;
hb_mask_t mask;
hb_mask_t _1_mask; /* mask for value=1, for quick access */
@@ -94,6 +93,21 @@
{ return a->index < b->index ? -1 : a->index > b->index ? 1 : 0; }
};
+ typedef union {
+ void *p;
+ gsub_pause_func_t gsub;
+ gpos_pause_func_t gpos;
+ } pause_func_t;
+ typedef struct {
+ pause_func_t func;
+ void *user_data;
+ } pause_callback_t;
+
+ struct pause_map_t {
+ unsigned int num_lookups; /* Cumulative */
+ pause_callback_t callback;
+ };
+
HB_INTERNAL void add_lookups (hb_face_t *face,
unsigned int table_index,
unsigned int feature_index,
@@ -104,6 +118,7 @@
hb_prealloced_array_t<feature_map_t, 8> features;
hb_prealloced_array_t<lookup_map_t, 32> lookups[2]; /* GSUB/GPOS */
+ hb_prealloced_array_t<pause_map_t, 1> pauses[2]; /* GSUB/GPOS */
};
@@ -116,12 +131,17 @@
inline void add_bool_feature (hb_tag_t tag, bool global = true)
{ add_feature (tag, 1, global); }
+ HB_INTERNAL void add_gsub_pause (hb_ot_map_t::gsub_pause_func_t pause_func, void *user_data);
+ HB_INTERNAL void add_gpos_pause (hb_ot_map_t::gpos_pause_func_t pause_func, void *user_data);
+
HB_INTERNAL void compile (hb_face_t *face,
const hb_segment_properties_t *props,
struct hb_ot_map_t &m);
inline void finish (void) {
feature_infos.finish ();
+ pauses[0].finish ();
+ pauses[1].finish ();
}
private:
@@ -132,12 +152,20 @@
unsigned int max_value;
bool global; /* whether the feature applies value to every glyph in the buffer */
unsigned int default_value; /* for non-global features, what should the unset glyphs take */
+ unsigned int stage[2]; /* GSUB/GPOS */
static int cmp (const feature_info_t *a, const feature_info_t *b)
{ return (a->tag != b->tag) ? (a->tag < b->tag ? -1 : 1) : (a->seq < b->seq ? -1 : 1); }
};
- hb_prealloced_array_t<feature_info_t,16> feature_infos; /* used before compile() only */
+ struct pause_info_t {
+ unsigned int stage;
+ hb_ot_map_t::pause_callback_t callback;
+ };
+
+ unsigned int current_stage[2]; /* GSUB/GPOS */
+ hb_prealloced_array_t<feature_info_t,16> feature_infos;
+ hb_prealloced_array_t<pause_info_t, 1> pauses[2]; /* GSUB/GPOS */
};
