diff --git a/TODO b/TODO
index efcee6a4a..17ee8b88f 100644
--- a/TODO
+++ b/TODO
@@ -1,6 +1,7 @@
 - cmap14 support in get_glyph callback
 - Use size_t in sanitize?
 - Buffer error handling?
+- Better define HB_INTERNAL
 
 hb-ot:
 - Fix ot query APIs
diff --git a/src/hb-font-private.h b/src/hb-font-private.h
index 3d695d7fe..4293b7e2d 100644
--- a/src/hb-font-private.h
+++ b/src/hb-font-private.h
@@ -44,10 +44,10 @@ struct _hb_font_funcs_t {
 
   hb_bool_t immutable;
 
-  hb_font_get_glyph_func_t glyph_func;
-  hb_font_get_contour_point_func_t contour_point_func;
-  hb_font_get_glyph_metrics_func_t glyph_metrics_func;
-  hb_font_get_kerning_func_t kerning_func;
+  hb_font_get_glyph_func_t		get_glyph;
+  hb_font_get_contour_point_func_t	get_contour_point;
+  hb_font_get_glyph_metrics_func_t	get_glyph_metrics;
+  hb_font_get_kerning_func_t		get_kerning;
 };
 
 HB_INTERNAL hb_font_funcs_t
diff --git a/src/hb-font.cc b/src/hb-font.cc
index 3108f5250..ff9b67b8b 100644
--- a/src/hb-font.cc
+++ b/src/hb-font.cc
@@ -32,19 +32,43 @@
 
 #include "hb-ot-layout-private.h"
 
+#include <string.h>
+
+
 /*
  * hb_font_funcs_t
  */
 
+static hb_codepoint_t
+hb_font_get_glyph_nil (hb_font_t *font, hb_face_t *face, const void *user_data,
+		       hb_codepoint_t unicode, hb_codepoint_t variant_selector)
+{ return unicode; }
+
+static hb_bool_t
+hb_font_get_contour_point_nil (hb_font_t *font, hb_face_t *face, const void *user_data,
+			       unsigned int point_index,
+			       hb_codepoint_t glyph, hb_position_t *x, hb_position_t *y)
+{ return false; }
+
+static void
+hb_font_get_glyph_metrics_nil (hb_font_t *font, hb_face_t *face, const void *user_data,
+			       hb_codepoint_t glyph, hb_glyph_metrics_t *metrics)
+{ memset (metrics, 0, sizeof (*metrics)); }
+
+static hb_position_t
+hb_font_get_kerning_nil (hb_font_t *font, hb_face_t *face, const void *user_data,
+			 hb_codepoint_t first_glyph, hb_codepoint_t second_glyph)
+{ return 0; }
+
 hb_font_funcs_t _hb_font_funcs_nil = {
   HB_REFERENCE_COUNT_INVALID, /* ref_count */
 
   TRUE,  /* immutable */
 
-  NULL, /* glyph_func */
-  NULL, /* contour_point_func */
-  NULL, /* glyph_metrics_func */
-  NULL  /* kerning_func */
+  hb_font_get_glyph_nil,
+  hb_font_get_contour_point_nil,
+  hb_font_get_glyph_metrics_nil,
+  hb_font_get_kerning_nil
 };
 
 hb_font_funcs_t *
@@ -105,6 +129,46 @@ hb_font_funcs_make_immutable (hb_font_funcs_t *ffuncs)
 }
 
 
+void
+hb_font_funcs_set_glyph_func (hb_font_funcs_t *ffuncs,
+			      hb_font_get_glyph_func_t glyph_func)
+{
+  if (ffuncs->immutable)
+    return;
+
+  ffuncs->get_glyph = glyph_func ? glyph_func : hb_font_get_glyph_nil;
+}
+
+void
+hb_font_funcs_set_contour_point_func (hb_font_funcs_t *ffuncs,
+				      hb_font_get_contour_point_func_t contour_point_func)
+{
+  if (ffuncs->immutable)
+    return;
+
+  ffuncs->get_contour_point = contour_point_func ? contour_point_func : hb_font_get_contour_point_nil;
+}
+
+void
+hb_font_funcs_set_glyph_metrics_func (hb_font_funcs_t *ffuncs,
+				      hb_font_get_glyph_metrics_func_t glyph_metrics_func)
+{
+  if (ffuncs->immutable)
+    return;
+
+  ffuncs->get_glyph_metrics = glyph_metrics_func ? glyph_metrics_func : hb_font_get_glyph_metrics_nil;
+}
+
+void
+hb_font_funcs_set_kerning_func (hb_font_funcs_t *ffuncs,
+				hb_font_get_kerning_func_t kerning_func)
+{
+  if (ffuncs->immutable)
+    return;
+
+  ffuncs->get_kerning = kerning_func ? kerning_func : hb_font_get_kerning_nil;
+}
+
 
 /*
  * hb_face_t
diff --git a/src/hb-font.h b/src/hb-font.h
index 153279ff9..aa47aed13 100644
--- a/src/hb-font.h
+++ b/src/hb-font.h
@@ -92,16 +92,15 @@ hb_font_funcs_make_immutable (hb_font_funcs_t *ffuncs);
 
 /* funcs */
 
-typedef struct _hb_glyph_metrics_t hb_glyph_metrics_t;
-struct _hb_glyph_metrics_t
+typedef struct _hb_glyph_metrics_t
 {
+    hb_position_t x_pos;
+    hb_position_t y_pos;
     hb_position_t x_advance;
     hb_position_t y_advance;
-    hb_position_t x_offset;
-    hb_position_t y_offset;
     hb_position_t width;
     hb_position_t height;
-};
+} hb_glyph_metrics_t;
 
 typedef hb_codepoint_t (*hb_font_get_glyph_func_t) (hb_font_t *font, hb_face_t *face, const void *user_data,
 						    hb_codepoint_t unicode, hb_codepoint_t variant_selector);
diff --git a/src/hb-ot-layout-gpos-private.hh b/src/hb-ot-layout-gpos-private.hh
index 5d9fd48e0..deea9b975 100644
--- a/src/hb-ot-layout-gpos-private.hh
+++ b/src/hb-ot-layout-gpos-private.hh
@@ -176,7 +176,8 @@ struct AnchorFormat2
   inline void get_anchor (hb_ot_layout_context_t *context, hb_codepoint_t glyph_id,
 			  hb_position_t *x, hb_position_t *y) const
   {
-      /* TODO Contour */
+      /* TODO Contour
+       * NOTE only adjust directions with nonzero ppem */
       *x = _hb_16dot16_mul_trunc (context->font->x_scale, xCoordinate);
       *y = _hb_16dot16_mul_trunc (context->font->y_scale, yCoordinate);
   }
@@ -856,12 +857,12 @@ struct CursivePosFormat1
     if (buffer->direction == HB_DIRECTION_RTL)
     {
       POSITION (buffer->in_pos)->x_advance   = entry_x - gpi->anchor_x;
-      POSITION (buffer->in_pos)->new_advance = TRUE;
+      POSITION (buffer->in_pos)->new_advance = true;
     }
     else
     {
       POSITION (last_pos)->x_advance   = gpi->anchor_x - entry_x;
-      POSITION (last_pos)->new_advance = TRUE;
+      POSITION (last_pos)->new_advance = true;
     }
 
     if  (lookup_flag & LookupFlag::RightToLeft)
diff --git a/src/hb-ot-layout-gsub-private.hh b/src/hb-ot-layout-gsub-private.hh
index dde1cf5ab..c240e86cf 100644
--- a/src/hb-ot-layout-gsub-private.hh
+++ b/src/hb-ot-layout-gsub-private.hh
@@ -372,7 +372,7 @@ struct Ligature
       }
 
       if (!(property & HB_OT_LAYOUT_GLYPH_CLASS_MARK))
-	is_mark = FALSE;
+	is_mark = false;
 
       if (HB_LIKELY (IN_GLYPH (j) != component[i]))
         return false;
diff --git a/src/hb-private.h b/src/hb-private.h
index c9f2ae7a6..caa0a5c6c 100644
--- a/src/hb-private.h
+++ b/src/hb-private.h
@@ -151,15 +151,15 @@ typedef int hb_mutex_t;
 	ASSERT_STATIC (sizeof (_type) == (_size) + VAR * sizeof (_var_type1) + VAR * sizeof (_var_type2))
 
 #if defined(__GNUC__) && (__GNUC__ > 2) && defined(__OPTIMIZE__)
-#define _HB_BOOLEAN_EXPR(expr)                   \
- __extension__ ({                               \
-   int _cairo_boolean_var_;                         \
-   if (expr)                                    \
-      _cairo_boolean_var_ = 1;                      \
-   else                                         \
-      _cairo_boolean_var_ = 0;                      \
-   _cairo_boolean_var_;                             \
-})
+#define _HB_BOOLEAN_EXPR(expr) \
+  __extension__ ({ \
+     int _hb_boolean_var_; \
+     if (expr) \
+	_hb_boolean_var_ = 1; \
+     else \
+	_hb_boolean_var_ = 0; \
+     _hb_boolean_var_; \
+  })
 #define HB_LIKELY(expr) (__builtin_expect (_HB_BOOLEAN_EXPR(expr), 1))
 #define HB_UNLIKELY(expr) (__builtin_expect (_HB_BOOLEAN_EXPR(expr), 0))
 #else