[aat] Allow enabling/disabling features

Only works at entire-buffer range, not sub-ranges.

Test with:

$ hb-shape Zapfino.dfont Zapfino
[Z_a_p_f_i_n_o=0+2333]

$ hb-shape Zapfino.dfont Zapfino --features=-dlig
[Z=0+416|a=1@-21,0+264|p_f=2+433|i=4+181|n=5+261|o=6+250]

$ hb-shape Zapfino.dfont Zapfino --features=+dlig
[Z_a_p_f_i_n_o=0+2333]

Fixes https://github.com/harfbuzz/harfbuzz/issues/1303

src/Makefile.sources

@@ -101,6 +101,8 @@ HB_OT_sources = \
 	hb-aat-layout-trak-table.hh \
 	hb-aat-layout.hh \
 	hb-aat-ltag-table.hh \
+	hb-aat-map.cc \
+	hb-aat-map.hh \
 	hb-ot-face.hh \
 	hb-ot-face.cc \
 	hb-ot-font.cc \

src/hb-aat-layout-morx-table.hh

@@ -30,6 +30,7 @@
 #include "hb-open-type.hh"
 #include "hb-aat-layout-common.hh"
 #include "hb-ot-layout-common.hh"
+#include "hb-aat-map.hh"
 
 /*
  * morx -- Extended Glyph Metamorphosis
@@ -839,9 +840,9 @@ struct ChainSubtable
 
 struct Chain
 {
-  inline void apply (hb_aat_apply_context_t *c) const
+  inline hb_mask_t compile_flags (const hb_aat_map_builder_t *map) const
   {
-    uint32_t flags = defaultFlags;
+    hb_mask_t flags = defaultFlags;
     {
       /* Compute applicable flags.  TODO Should move this to planning
        * stage and take user-requested features into account. */
@@ -849,14 +850,22 @@ struct Chain
       for (unsigned i = 0; i < count; i++)
       {
         const Feature &feature = featureZ[i];
-	if (false) /* XXX Check if feature enabled... */
+        uint16_t type = feature.featureType;
+	uint16_t setting = feature.featureSetting;
+	const hb_aat_map_builder_t::feature_info_t *info = map->features.bsearch (type);
+	if (info && info->setting == setting)
 	{
 	  flags &= feature.disableFlags;
 	  flags |= feature.enableFlags;
 	}
       }
     }
+    return flags;
+  }
 
+  inline void apply (hb_aat_apply_context_t *c,
+		     hb_mask_t flags) const
+  {
     const ChainSubtable *subtable = &StructAtOffset<ChainSubtable> (&featureZ, featureZ[0].static_size * featureCount);
     unsigned int count = subtableCount;
     for (unsigned int i = 0; i < count; i++)
@@ -976,6 +985,18 @@ struct morx
 
   inline bool has_data (void) const { return version != 0; }
 
+  inline void compile_flags (const hb_aat_map_builder_t *mapper,
+			     hb_aat_map_t *map) const
+  {
+    const Chain *chain = &firstChain;
+    unsigned int count = chainCount;
+    for (unsigned int i = 0; i < count; i++)
+    {
+      map->chain_flags.push (chain->compile_flags (mapper));
+      chain = &StructAfter<Chain> (*chain);
+    }
+  }
+
   inline void apply (hb_aat_apply_context_t *c) const
   {
     if (unlikely (!c->buffer->successful)) return;
@@ -984,7 +1005,7 @@ struct morx
     unsigned int count = chainCount;
     for (unsigned int i = 0; i < count; i++)
     {
-      chain->apply (c);
+      chain->apply (c, c->plan->aat_map.chain_flags[i]);
       if (unlikely (!c->buffer->successful)) return;
       chain = &StructAfter<Chain> (*chain);
     }

src/hb-aat-layout.cc

@@ -183,6 +183,14 @@ _get_trak (hb_face_t *face)
 }
 
 
+void
+hb_aat_layout_compile_map (const hb_aat_map_builder_t *mapper,
+			   hb_aat_map_t *map)
+{
+  _get_morx (mapper->face).compile_flags (mapper, map);
+}
+
+
 hb_bool_t
 hb_aat_layout_has_substitution (hb_face_t *face)
 {

src/hb-aat-layout.hh

@@ -52,6 +52,9 @@ struct hb_aat_feature_mapping_t
 HB_INTERNAL const hb_aat_feature_mapping_t *
 hb_aat_layout_find_feature_mapping (hb_tag_t tag);
 
+HB_INTERNAL void
+hb_aat_layout_compile_map (const hb_aat_map_builder_t *mapper,
+			   hb_aat_map_t *map);
 
 HB_INTERNAL hb_bool_t
 hb_aat_layout_has_substitution (hb_face_t *face);

src/hb-ot-shape.cc

@@ -57,6 +57,7 @@ hb_ot_shape_planner_t::hb_ot_shape_planner_t (const hb_shape_plan_t *master_plan
 						face (master_plan->face_unsafe),
 						props (master_plan->props),
 						map (face, &props),
+						aat_map (face, &props),
 						apply_morx (_hb_apply_morx (face)),
 						shaper (apply_morx ?
 						        &_hb_ot_complex_shaper_default :
@@ -70,6 +71,7 @@ hb_ot_shape_planner_t::compile (hb_ot_shape_plan_t &plan,
   plan.props = props;
   plan.shaper = shaper;
   map.compile (plan.map, coords, num_coords);
+  aat_map.compile (plan.aat_map, coords, num_coords);
 
   plan.frac_mask = plan.map.get_1_mask (HB_TAG ('f','r','a','c'));
   plan.numr_mask = plan.map.get_1_mask (HB_TAG ('n','u','m','r'));
@@ -160,6 +162,7 @@ hb_ot_shape_collect_features (hb_ot_shape_planner_t          *planner,
 			      unsigned int                    num_user_features)
 {
   hb_ot_map_builder_t *map = &planner->map;
+  hb_aat_map_builder_t *aat_map = &planner->aat_map;
 
   map->enable_feature (HB_TAG('r','v','r','n'));
   map->add_gsub_pause (nullptr);
@@ -225,6 +228,7 @@ hb_ot_shape_collect_features (hb_ot_shape_planner_t          *planner,
 		      (feature->start == HB_FEATURE_GLOBAL_START &&
 		       feature->end == HB_FEATURE_GLOBAL_END) ?  F_GLOBAL : F_NONE,
 		      feature->value);
+    aat_map->add_feature (feature->tag, feature->value);
   }
 }
 

src/hb-ot-shape.hh

@@ -30,6 +30,7 @@
 #include "hb.hh"
 
 #include "hb-ot-map.hh"
+#include "hb-aat-map.hh"
 #include "hb-shape-plan.hh"
 
 
@@ -39,6 +40,7 @@ struct hb_ot_shape_plan_t
   hb_segment_properties_t props;
   const struct hb_ot_complex_shaper_t *shaper;
   hb_ot_map_t map;
+  hb_aat_map_t aat_map;
   const void *data;
   hb_mask_t frac_mask, numr_mask, dnom_mask;
   hb_mask_t rtlm_mask;
@@ -77,9 +79,11 @@ struct hb_ot_shape_plan_t
   {
     memset (this, 0, sizeof (*this));
     map.init ();
+    aat_map.init ();
   }
   void fini (void) {
     map.fini ();
+    aat_map.fini ();
   }
 };
 
@@ -89,6 +93,7 @@ struct hb_ot_shape_planner_t
   hb_face_t *face;
   hb_segment_properties_t props;
   hb_ot_map_builder_t map;
+  hb_aat_map_builder_t aat_map;
   bool apply_morx : 1;
   const struct hb_ot_complex_shaper_t *shaper;