[GPOS] Cache VarStore region scalars

src/hb-ot-layout-common.hh

@@ -3010,7 +3010,9 @@ struct VariationStore
 
   protected:
   HBUINT16				format;
+  public:
   Offset32To<VarRegionList>		regions;
+  protected:
   Array16OfOffset32To<VarData>		dataSets;
   public:
   DEFINE_SIZE_ARRAY_SIZED (8, dataSets);

src/hb-ot-layout-gpos-table.hh

@@ -146,23 +146,24 @@ struct ValueFormat : HBUINT16
     if (!use_x_device && !use_y_device) return ret;
 
     const VariationStore &store = c->var_store;
+    auto *cache = &c->regions_cache;
 
     /* pixel -> fractional pixel */
     if (format & xPlaDevice) {
-      if (use_x_device) glyph_pos.x_offset  += (base + get_device (values, &ret)).get_x_delta (font, store);
+      if (use_x_device) glyph_pos.x_offset  += (base + get_device (values, &ret)).get_x_delta (font, store, cache);
       values++;
     }
     if (format & yPlaDevice) {
-      if (use_y_device) glyph_pos.y_offset  += (base + get_device (values, &ret)).get_y_delta (font, store);
+      if (use_y_device) glyph_pos.y_offset  += (base + get_device (values, &ret)).get_y_delta (font, store, cache);
       values++;
     }
     if (format & xAdvDevice) {
-      if (horizontal && use_x_device) glyph_pos.x_advance += (base + get_device (values, &ret)).get_x_delta (font, store);
+      if (horizontal && use_x_device) glyph_pos.x_advance += (base + get_device (values, &ret)).get_x_delta (font, store, cache);
       values++;
     }
     if (format & yAdvDevice) {
       /* y_advance values grow downward but font-space grows upward, hence negation */
-      if (!horizontal && use_y_device) glyph_pos.y_advance -= (base + get_device (values, &ret)).get_y_delta (font, store);
+      if (!horizontal && use_y_device) glyph_pos.y_advance -= (base + get_device (values, &ret)).get_y_delta (font, store, cache);
       values++;
     }
     return ret;
@@ -465,9 +466,9 @@ struct AnchorFormat3
     *y = font->em_fscale_y (yCoordinate);
 
     if (font->x_ppem || font->num_coords)
-      *x += (this+xDeviceTable).get_x_delta (font, c->var_store);
+      *x += (this+xDeviceTable).get_x_delta (font, c->var_store, &c->regions_cache);
     if (font->y_ppem || font->num_coords)
-      *y += (this+yDeviceTable).get_y_delta (font, c->var_store);
+      *y += (this+yDeviceTable).get_y_delta (font, c->var_store, &c->regions_cache);
   }
 
   bool sanitize (hb_sanitize_context_t *c) const

src/hb-ot-layout-gsubgpos.hh

@@ -627,6 +627,7 @@ struct hb_ot_apply_context_t :
   recurse_func_t recurse_func;
   const GDEF &gdef;
   const VariationStore &var_store;
+  hb_vector_t<float> regions_cache;
 
   hb_direction_t direction;
   hb_mask_t lookup_mask;
@@ -669,7 +670,16 @@ struct hb_ot_apply_context_t :
 			auto_zwj (true),
 			per_syllable (false),
 			random (false),
-			random_state (1) { init_iters (); }
+			random_state (1)
+  {
+    init_iters ();
+    if (table_index == 1 && font->num_coords) /* GPOS */
+    {
+      regions_cache.resize ((&var_store+var_store.regions).regionCount);
+      for (auto &f : regions_cache.writer ())
+        f = NAN;
+    }
+  }
 
   void init_iters ()
   {