1 files changed, 24 insertions, 1 deletions
diff --git a/gfx/harfbuzz/src/hb-subset-plan.hh b/gfx/harfbuzz/src/hb-subset-plan.hh
index 1f19a58c1e..19a9fa6918 100644
--- a/gfx/harfbuzz/src/hb-subset-plan.hh
+++ b/gfx/harfbuzz/src/hb-subset-plan.hh
@@ -78,6 +78,13 @@ struct contour_point_t
 	  y  = x * matrix[1] + y * matrix[3];
     x  = x_;
   }
+
+  void add_delta (float delta_x, float delta_y)
+  {
+    x += delta_x;
+    y += delta_y;
+  }
+
   HB_ALWAYS_INLINE
   void translate (const contour_point_t &p) { x += p.x; y += p.y; }
 
@@ -99,6 +106,22 @@ struct contour_point_vector_t : hb_vector_t<contour_point_t>
     unsigned count = a.length;
     hb_memcpy (arrayZ, a.arrayZ, count * sizeof (arrayZ[0]));
   }
+
+  bool add_deltas (const hb_vector_t<float> deltas_x,
+                   const hb_vector_t<float> deltas_y,
+                   const hb_vector_t<bool> indices)
+  {
+    if (indices.length != deltas_x.length ||
+        indices.length != deltas_y.length)
+      return false;
+
+    for (unsigned i = 0; i < indices.length; i++)
+    {
+      if (!indices.arrayZ[i]) continue;
+      arrayZ[i].add_delta (deltas_x.arrayZ[i], deltas_y.arrayZ[i]);
+    }
+    return true;
+  }
 };
 
 namespace OT {
@@ -147,7 +170,7 @@ struct hb_subset_plan_t
   bool gsub_insert_catch_all_feature_variation_rec;
   bool gpos_insert_catch_all_feature_variation_rec;
 
-  // whether GDEF VarStore is retained
+  // whether GDEF ItemVariationStore is retained
   mutable bool has_gdef_varstore;
 
 #define HB_SUBSET_PLAN_MEMBER(Type, Name) Type Name;