diff --git a/src/hb-aat-layout-common-private.hh b/src/hb-aat-layout-common-private.hh
index c93661c34..b1165e9bf 100644
--- a/src/hb-aat-layout-common-private.hh
+++ b/src/hb-aat-layout-common-private.hh
@@ -691,6 +691,29 @@ struct StateTableDriver
 };
 
 
+
+struct hb_aat_apply_context_t :
+       hb_dispatch_context_t<hb_aat_apply_context_t, bool, HB_DEBUG_APPLY>
+{
+  inline const char *get_name (void) { return "APPLY"; }
+  template <typename T>
+  inline return_t dispatch (const T &obj) { return obj.apply (this); }
+  static return_t default_return_value (void) { return false; }
+  bool stop_sublookup_iteration (return_t r) const { return r; }
+
+  hb_font_t *font;
+  hb_face_t *face;
+  hb_buffer_t *buffer;
+  const char *end;
+
+  hb_aat_apply_context_t (hb_font_t *font_,
+			  hb_buffer_t *buffer_,
+			  const char *end_) :
+			font (font_), face (font->face), buffer (buffer_),
+			end (end_) {}
+};
+
+
 } /* namespace AAT */
 
 
diff --git a/src/hb-aat-layout-morx-table.hh b/src/hb-aat-layout-morx-table.hh
index 419185c5a..5b3402be5 100644
--- a/src/hb-aat-layout-morx-table.hh
+++ b/src/hb-aat-layout-morx-table.hh
@@ -148,7 +148,7 @@ struct RearrangementSubtable
     unsigned int last_zero_before_start;
   };
 
-  inline bool apply (hb_ot_apply_context_t *c) const
+  inline bool apply (hb_aat_apply_context_t *c) const
   {
     TRACE_APPLY (this);
 
@@ -245,7 +245,7 @@ struct ContextualSubtable
     const UnsizedOffsetListOf<Lookup<GlyphID>, HBUINT32> &subs;
   };
 
-  inline bool apply (hb_ot_apply_context_t *c) const
+  inline bool apply (hb_aat_apply_context_t *c) const
   {
     TRACE_APPLY (this);
 
@@ -326,7 +326,7 @@ struct LigatureSubtable
     private:
   };
 
-  inline bool apply (hb_ot_apply_context_t *c) const
+  inline bool apply (hb_aat_apply_context_t *c) const
   {
     TRACE_APPLY (this);
 
@@ -360,7 +360,7 @@ struct LigatureSubtable
 
 struct NoncontextualSubtable
 {
-  inline bool apply (hb_ot_apply_context_t *c) const
+  inline bool apply (hb_aat_apply_context_t *c) const
   {
     TRACE_APPLY (this);
 
@@ -396,7 +396,7 @@ struct NoncontextualSubtable
 
 struct InsertionSubtable
 {
-  inline bool apply (hb_ot_apply_context_t *c) const
+  inline bool apply (hb_aat_apply_context_t *c) const
   {
     TRACE_APPLY (this);
     /* TODO */
@@ -448,13 +448,13 @@ struct ChainSubtable
     Insertion		= 5
   };
 
-  inline void apply (hb_ot_apply_context_t *c, const char *end) const
+  inline void apply (hb_aat_apply_context_t *c) const
   {
-    dispatch (c, end);
+    dispatch (c);
   }
 
   template <typename context_t>
-  inline typename context_t::return_t dispatch (context_t *c, const char *end) const
+  inline typename context_t::return_t dispatch (context_t *c) const
   {
     unsigned int subtable_type = get_type ();
     TRACE_DISPATCH (this, subtable_type);
@@ -476,7 +476,7 @@ struct ChainSubtable
 	!c->check_range (this, length))
       return_trace (false);
 
-    return_trace (dispatch (c, c->end));
+    return_trace (dispatch (c));
   }
 
   protected:
@@ -496,13 +496,13 @@ struct ChainSubtable
 
 struct Chain
 {
-  inline void apply (hb_ot_apply_context_t *c, const char *end) const
+  inline void apply (hb_aat_apply_context_t *c) const
   {
     const ChainSubtable *subtable = &StructAtOffset<ChainSubtable> (featureZ, featureZ[0].static_size * featureCount);
     unsigned int count = subtableCount;
     for (unsigned int i = 0; i < count; i++)
     {
-      subtable->apply (c, end);
+      subtable->apply (c);
       subtable = &StructAfter<ChainSubtable> (*subtable);
     }
   }
@@ -555,14 +555,13 @@ struct morx
 {
   static const hb_tag_t tableTag = HB_AAT_TAG_MORX;
 
-  inline void apply (hb_ot_apply_context_t *c, unsigned int length) const
+  inline void apply (hb_aat_apply_context_t *c) const
   {
-    const char *end = (const char *) this + length;
     const Chain *chain = chains;
     unsigned int count = chainCount;
     for (unsigned int i = 0; i < count; i++)
     {
-      chain->apply (c, end);
+      chain->apply (c);
       chain = &StructAfter<Chain> (*chain);
     }
   }
diff --git a/src/hb-aat-layout-private.hh b/src/hb-aat-layout-private.hh
index ebddf3b40..c1c607a2f 100644
--- a/src/hb-aat-layout-private.hh
+++ b/src/hb-aat-layout-private.hh
@@ -35,6 +35,6 @@
 
 
 HB_INTERNAL void
-hb_aat_layout_substitute (OT::hb_ot_apply_context_t *c);
+hb_aat_layout_substitute (hb_font_t *font, hb_buffer_t *buffer);
 
 #endif /* HB_AAT_LAYOUT_PRIVATE_HH */
diff --git a/src/hb-aat-layout.cc b/src/hb-aat-layout.cc
index 94e1442d6..465aec642 100644
--- a/src/hb-aat-layout.cc
+++ b/src/hb-aat-layout.cc
@@ -68,9 +68,11 @@ _hb_aat_layout_create (hb_face_t *face)
 }
 
 void
-hb_aat_layout_substitute (OT::hb_ot_apply_context_t *c)
+hb_aat_layout_substitute (hb_font_t *font, hb_buffer_t *buffer)
 {
   unsigned int length;
-  const AAT::morx& morx = _get_morx (c->face, &length);
-  morx.apply (c, length);
+  const AAT::morx& morx = _get_morx (font->face, &length);
+
+  AAT::hb_aat_apply_context_t c (font, buffer, (const char *) &morx + length);
+  morx.apply (&c);
 }
diff --git a/src/hb-ot-shape.cc b/src/hb-ot-shape.cc
index 3076586d7..fc5dd1084 100644
--- a/src/hb-ot-shape.cc
+++ b/src/hb-ot-shape.cc
@@ -619,8 +619,7 @@ hb_ot_substitute_complex (hb_ot_shape_context_t *c)
   c->plan->substitute (c->font, buffer);
 
   /* XXX Call morx instead. */
-  //OT::hb_ot_apply_context_t ac (0, c->font, c->buffer);
-  //hb_aat_layout_substitute (&ac);
+  //hb_aat_layout_substitute (c->font, c->buffer);
 }
 
 static inline void