fix empty glyf's advance width

src/hb-ot-glyf-table.hh

@@ -418,7 +418,13 @@ struct glyf
       unsigned int num_points = 0;
       unsigned int start_offset, end_offset;
       if (unlikely (!get_offsets (glyph, &start_offset, &end_offset))) return false;
-      if (unlikely (end_offset - start_offset < GlyphHeader::static_size)) return false;
+      if (unlikely (end_offset - start_offset < GlyphHeader::static_size))
+      {
+      	/* empty glyph */
+	points_.resize (PHANTOM_COUNT);
+	for (unsigned int i = 0; i < points_.length; i++) points_[i].init ();
+      	return true;
+      }
 
       CompositeGlyphHeader::Iterator composite;
       if (get_composite (glyph, &composite))

src/hb-ot-hmtx-table.cc

@@ -37,7 +37,7 @@ int hmtxvmtx_accelerator_base_t::get_side_bearing_var_tt (hb_font_t *font, hb_co
   float side_bearing = glyf_accel.get_side_bearing_var (glyph, font->coords, font->num_coords, vertical);
   glyf_accel.fini ();
 
-  return (int)side_bearing;
+  return (int)roundf (side_bearing);
 }
 
 unsigned int hmtxvmtx_accelerator_base_t::get_advance_var_tt (hb_font_t *font, hb_codepoint_t glyph, bool vertical)
@@ -48,7 +48,7 @@ unsigned int hmtxvmtx_accelerator_base_t::get_advance_var_tt (hb_font_t *font, h
   float advance = glyf_accel.get_advance_var (glyph, font->coords, font->num_coords, vertical);
   glyf_accel.fini ();
 
-  return (unsigned int)advance;
+  return (unsigned int)roundf (advance);
 }
 
 }