[instancer] Add new_gid->contour_points vector map in subset plan

- Add an API in Glyph to export original contour_points vector, which is
  needed by infer_deltas when merging tuple variations with the same
  tent

src/OT/glyf/Glyph.hh

@@ -103,6 +103,63 @@ struct Glyph
     }
   }
 
+  bool get_all_points_without_var (const hb_face_t *face,
+                                   contour_point_vector_t &points /* OUT */) const
+  {
+    switch (type) {
+    case SIMPLE:
+      if (unlikely (!SimpleGlyph (*header, bytes).get_contour_points (points)))
+        return false;
+      break;
+    case COMPOSITE:
+    {
+      for (auto &item : get_composite_iterator ())
+        if (unlikely (!item.get_points (points))) return false;
+      break;
+    }
+#ifndef HB_NO_VAR_COMPOSITES
+    case VAR_COMPOSITE:
+    {
+      for (auto &item : get_var_composite_iterator ())
+        if (unlikely (!item.get_points (points))) return false;
+      break;
+    }
+#endif
+    case EMPTY:
+      break;
+    }
+
+    /* Init phantom points */
+    if (unlikely (!points.resize (points.length + PHANTOM_COUNT))) return false;
+    hb_array_t<contour_point_t> phantoms = points.as_array ().sub_array (points.length - PHANTOM_COUNT, PHANTOM_COUNT);
+    {
+      int lsb = 0;
+      int h_delta = face->table.hmtx->get_leading_bearing_without_var_unscaled (gid, &lsb) ?
+                    (int) header->xMin - lsb : 0;
+      HB_UNUSED int tsb = 0;
+      int v_orig  = (int) header->yMax +
+#ifndef HB_NO_VERTICAL
+                    ((void) face->table.vmtx->get_leading_bearing_without_var_unscaled (gid, &tsb), tsb)
+#else
+                    0
+#endif
+                    ;
+      unsigned h_adv = face->table.hmtx->get_advance_without_var_unscaled (gid);
+      unsigned v_adv =
+#ifndef HB_NO_VERTICAL
+                       face->table.vmtx->get_advance_without_var_unscaled (gid)
+#else
+                       - face->get_upem ()
+#endif
+                       ;
+      phantoms[PHANTOM_LEFT].x = h_delta;
+      phantoms[PHANTOM_RIGHT].x = (int) h_adv + h_delta;
+      phantoms[PHANTOM_TOP].y = v_orig;
+      phantoms[PHANTOM_BOTTOM].y = v_orig - (int) v_adv;
+    }
+    return true;
+  }
+
   void update_mtx (const hb_subset_plan_t *plan,
                    int xMin, int xMax,
                    int yMin, int yMax,

src/hb-ot-var-gvar-table.hh

@@ -39,40 +39,6 @@
 
 namespace OT {
 
-struct contour_point_t
-{
-  void init (float x_ = 0.f, float y_ = 0.f, bool is_end_point_ = false)
-  { flag = 0; x = x_; y = y_; is_end_point = is_end_point_; }
-
-  void transform (const float (&matrix)[4])
-  {
-    float x_ = x * matrix[0] + y * matrix[2];
-	  y  = x * matrix[1] + y * matrix[3];
-    x  = x_;
-  }
-  HB_ALWAYS_INLINE
-  void translate (const contour_point_t &p) { x += p.x; y += p.y; }
-
-
-  float x;
-  float y;
-  uint8_t flag;
-  bool is_end_point;
-};
-
-struct contour_point_vector_t : hb_vector_t<contour_point_t>
-{
-  void extend (const hb_array_t<contour_point_t> &a)
-  {
-    unsigned int old_len = length;
-    if (unlikely (!resize (old_len + a.length, false)))
-      return;
-    auto arrayZ = this->arrayZ + old_len;
-    unsigned count = a.length;
-    hb_memcpy (arrayZ, a.arrayZ, count * sizeof (arrayZ[0]));
-  }
-};
-
 struct GlyphVariationData : TupleVariationData
 {};
 

src/hb-subset-plan-member-list.hh

@@ -123,6 +123,9 @@ HB_SUBSET_PLAN_MEMBER (mutable hb_vector_t<unsigned>, bounds_width_vec)
 //boundsHeight map: new gid->boundsHeight, boundsHeight=yMax - yMin
 HB_SUBSET_PLAN_MEMBER (mutable hb_vector_t<unsigned>, bounds_height_vec)
 
+//map: new_gid -> contour points vector
+HB_SUBSET_PLAN_MEMBER (mutable hb_hashmap_t E(<hb_codepoint_t, contour_point_vector_t>), new_gid_contour_points_map)
+
 #ifdef HB_EXPERIMENTAL_API
 // name table overrides map: hb_ot_name_record_ids_t-> name string new value or
 // None to indicate should remove

src/hb-subset-plan.cc

@@ -1045,6 +1045,36 @@ _update_instance_metrics_map_from_cff2 (hb_subset_plan_t *plan)
   if (vvar_store_cache)
     _vmtx.var_table->get_var_store ().destroy_cache (vvar_store_cache);
 }
+
+static bool
+_get_instance_glyphs_contour_points (hb_subset_plan_t *plan)
+{
+  /* contour_points vector only needed for updating gvar table (infer delta)
+   * during partial instancing */
+  if (plan->user_axes_location.is_empty () || plan->all_axes_pinned)
+    return true;
+
+  OT::glyf_accelerator_t glyf (plan->source);
+
+  for (auto &_ : plan->new_to_old_gid_list)
+  {
+    hb_codepoint_t new_gid = _.first;
+    contour_point_vector_t all_points;
+    if (new_gid == 0 && !(plan->flags & HB_SUBSET_FLAGS_NOTDEF_OUTLINE))
+    {
+      if (unlikely (!plan->new_gid_contour_points_map.set (new_gid, all_points)))
+        return false;
+      continue;
+    }
+
+    hb_codepoint_t old_gid = _.second;
+    if (unlikely (!glyf.glyph_for_gid (old_gid).get_all_points_without_var (plan->source, all_points)))
+      return false;
+    if (unlikely (!plan->new_gid_contour_points_map.set (new_gid, all_points)))
+      return false;
+  }
+  return true;
+}
 #endif
 
 hb_subset_plan_t::hb_subset_plan_t (hb_face_t *face,
@@ -1148,6 +1178,8 @@ hb_subset_plan_t::hb_subset_plan_t (hb_face_t *face,
 
 #ifndef HB_NO_VAR
   _update_instance_metrics_map_from_cff2 (this);
+  if (!check_success (_get_instance_glyphs_contour_points (this)))
+      return;
 #endif
 
   if (attach_accelerator_data)

src/hb-subset-plan.hh

@@ -67,6 +67,40 @@ struct head_maxp_info_t
 
 typedef struct head_maxp_info_t head_maxp_info_t;
 
+struct contour_point_t
+{
+  void init (float x_ = 0.f, float y_ = 0.f, bool is_end_point_ = false)
+  { flag = 0; x = x_; y = y_; is_end_point = is_end_point_; }
+
+  void transform (const float (&matrix)[4])
+  {
+    float x_ = x * matrix[0] + y * matrix[2];
+	  y  = x * matrix[1] + y * matrix[3];
+    x  = x_;
+  }
+  HB_ALWAYS_INLINE
+  void translate (const contour_point_t &p) { x += p.x; y += p.y; }
+
+
+  float x;
+  float y;
+  uint8_t flag;
+  bool is_end_point;
+};
+
+struct contour_point_vector_t : hb_vector_t<contour_point_t>
+{
+  void extend (const hb_array_t<contour_point_t> &a)
+  {
+    unsigned int old_len = length;
+    if (unlikely (!resize (old_len + a.length, false)))
+      return;
+    auto arrayZ = this->arrayZ + old_len;
+    unsigned count = a.length;
+    hb_memcpy (arrayZ, a.arrayZ, count * sizeof (arrayZ[0]));
+  }
+};
+
 namespace OT {
   struct cff1_subset_accelerator_t;
   struct cff2_subset_accelerator_t;