Don't cache ascender/descender metrics

src/hb-ot-font.cc

@@ -230,32 +230,24 @@ hb_ot_get_glyph_from_name (hb_font_t *font HB_UNUSED,
 
 static hb_bool_t
 hb_ot_get_font_h_extents (hb_font_t *font,
-			  void *font_data,
+			  void *font_data HB_UNUSED,
 			  hb_font_extents_t *metrics,
 			  void *user_data HB_UNUSED)
 {
-  const hb_ot_face_t *ot_face = (const hb_ot_face_t *) font_data;
-  const OT::hmtx_accelerator_t &hmtx = *ot_face->hmtx;
-  metrics->ascender = font->em_scale_y (hmtx.ascender);
-  metrics->descender = font->em_scale_y (hmtx.descender);
-  metrics->line_gap = font->em_scale_y (hmtx.line_gap);
-  // TODO Hook up variations.
-  return hmtx.has_font_extents;
+  return hb_ot_metrics_get_position (font, HB_OT_METRICS_HORIZONTAL_ASCENDER, &metrics->ascender) &&
+	 hb_ot_metrics_get_position (font, HB_OT_METRICS_HORIZONTAL_DESCENDER, &metrics->descender) &&
+	 hb_ot_metrics_get_position (font, HB_OT_METRICS_HORIZONTAL_LINE_GAP, &metrics->line_gap);
 }
 
 static hb_bool_t
 hb_ot_get_font_v_extents (hb_font_t *font,
-			  void *font_data,
+			  void *font_data HB_UNUSED,
 			  hb_font_extents_t *metrics,
 			  void *user_data HB_UNUSED)
 {
-  const hb_ot_face_t *ot_face = (const hb_ot_face_t *) font_data;
-  const OT::vmtx_accelerator_t &vmtx = *ot_face->vmtx;
-  metrics->ascender = font->em_scale_x (vmtx.ascender);
-  metrics->descender = font->em_scale_x (vmtx.descender);
-  metrics->line_gap = font->em_scale_x (vmtx.line_gap);
-  // TODO Hook up variations.
-  return vmtx.has_font_extents;
+  return hb_ot_metrics_get_position (font, HB_OT_METRICS_VERTICAL_ASCENDER, &metrics->ascender) &&
+	 hb_ot_metrics_get_position (font, HB_OT_METRICS_VERTICAL_DESCENDER, &metrics->descender) &&
+	 hb_ot_metrics_get_position (font, HB_OT_METRICS_VERTICAL_LINE_GAP, &metrics->line_gap);
 }
 
 #if HB_USE_ATEXIT

src/hb-ot-hmtx-table.hh

@@ -161,14 +161,6 @@ struct hmtxvmtx
                unsigned int default_advance_ = 0)
     {
       default_advance = default_advance_ ? default_advance_ : hb_face_get_upem (face);
-      ascender = 0; descender = 0; line_gap = 0;
-
-      hb_ot_metrics_get_position_internal (face, T::ascenderTag, &ascender);
-      hb_ot_metrics_get_position_internal (face, T::descenderTag, &descender);
-      hb_ot_metrics_get_position_internal (face, T::lineGapTag, &line_gap);
-      ascender = fabs (ascender);
-      descender = -fabs (descender);
-      has_font_extents = ascender != 0 || descender != 0;
 
       num_advances = T::is_horizontal ? face->table.hhea->numberOfLongMetrics : face->table.vhea->numberOfLongMetrics;
 
@@ -264,12 +256,6 @@ struct hmtxvmtx
       return get_advance (old_gid);
     }
 
-    public:
-    bool has_font_extents;
-    float ascender;
-    float descender;
-    float line_gap;
-
     protected:
     unsigned int num_metrics;
     unsigned int num_advances;
@@ -309,17 +295,11 @@ struct hmtxvmtx
 struct hmtx : hmtxvmtx<hmtx, hhea> {
   static constexpr hb_tag_t tableTag = HB_OT_TAG_hmtx;
   static constexpr hb_tag_t variationsTag = HB_OT_TAG_HVAR;
-  static constexpr hb_ot_metrics_t ascenderTag = HB_OT_METRICS_HORIZONTAL_ASCENDER;
-  static constexpr hb_ot_metrics_t descenderTag = HB_OT_METRICS_HORIZONTAL_DESCENDER;
-  static constexpr hb_ot_metrics_t lineGapTag = HB_OT_METRICS_HORIZONTAL_LINE_GAP;
   static constexpr bool is_horizontal = true;
 };
 struct vmtx : hmtxvmtx<vmtx, vhea> {
   static constexpr hb_tag_t tableTag = HB_OT_TAG_vmtx;
   static constexpr hb_tag_t variationsTag = HB_OT_TAG_VVAR;
-  static constexpr hb_ot_metrics_t ascenderTag = HB_OT_METRICS_VERTICAL_ASCENDER;
-  static constexpr hb_ot_metrics_t descenderTag = HB_OT_METRICS_VERTICAL_DESCENDER;
-  static constexpr hb_ot_metrics_t lineGapTag = HB_OT_METRICS_VERTICAL_LINE_GAP;
   static constexpr bool is_horizontal = false;
 };