Merge pull request #1844 from ebraminio/hhea

Fallback hhea's ascender/descender to OS2

src/hb-ot-metrics-internal.cc

@@ -60,14 +60,14 @@ hb_ot_metrics_get_position_internal (hb_face_t       *face,
   (face->table.TABLE->has_data () && \
     (position && (*position = face->table.TABLE->ATTR + GET_VAR), true))
   case HB_OT_METRICS_HORIZONTAL_ASCENDER:
-    return (face->table.OS2->use_typo_metrics () && GET_METRIC (OS2, sTypoAscender)) ||
-	   GET_METRIC (hhea, ascender);
+    return (!face->table.OS2->use_typo_metrics () && GET_METRIC (hhea, ascender)) ||
+	   GET_METRIC (OS2, sTypoAscender);
   case HB_OT_METRICS_HORIZONTAL_DESCENDER:
-    return (face->table.OS2->use_typo_metrics () && GET_METRIC (OS2, sTypoDescender)) ||
-	   GET_METRIC (hhea, descender);
+    return (!face->table.OS2->use_typo_metrics () && GET_METRIC (hhea, descender)) ||
+	   GET_METRIC (OS2, sTypoDescender);
   case HB_OT_METRICS_HORIZONTAL_LINE_GAP:
-    return (face->table.OS2->use_typo_metrics () && GET_METRIC (OS2, sTypoLineGap)) ||
-	   GET_METRIC (hhea, lineGap);
+    return (!face->table.OS2->use_typo_metrics () && GET_METRIC (hhea, lineGap)) ||
+	   GET_METRIC (OS2, sTypoLineGap);
   case HB_OT_METRICS_HORIZONTAL_CLIPPING_ASCENT:  return GET_METRIC (OS2, usWinAscent);
   case HB_OT_METRICS_HORIZONTAL_CLIPPING_DESCENT: return GET_METRIC (OS2, usWinDescent);
   case HB_OT_METRICS_VERTICAL_ASCENDER:           return GET_METRIC (vhea, ascender);

src/hb-ot-os2-table.hh

@@ -117,8 +117,8 @@ struct OS2
     OBLIQUE		= 1u<<9
   };
 
-  bool is_italic () const       { return fsSelection & ITALIC; }
-  bool is_oblique () const      { return fsSelection & OBLIQUE; }
+  bool is_italic () const        { return fsSelection & ITALIC; }
+  bool is_oblique () const       { return fsSelection & OBLIQUE; }
   bool use_typo_metrics () const { return fsSelection & USE_TYPO_METRICS; }
 
   enum width_class_t {
@@ -196,13 +196,14 @@ struct OS2
   }
 
   static void find_min_and_max_codepoint (const hb_set_t *codepoints,
-						 uint16_t *min_cp, /* OUT */
-						 uint16_t *max_cp  /* OUT */)
+					  uint16_t *min_cp, /* OUT */
+					  uint16_t *max_cp  /* OUT */)
   {
     *min_cp = codepoints->get_min ();
     *max_cp = codepoints->get_max ();
   }
 
+  /* https://github.com/Microsoft/Font-Validator/blob/520aaae/OTFontFileVal/val_OS2.cs#L644-L681 */
   enum font_page_t {
     HEBREW_FONT_PAGE		= 0xB100, // Hebrew Windows 3.1 font page
     SIMP_ARABIC_FONT_PAGE	= 0xB200, // Simplified Arabic Windows 3.1 font page
@@ -212,8 +213,6 @@ struct OS2
     TRAD_FARSI_FONT_PAGE	= 0xBB00, // Traditional Farsi Windows 3.1 font page
     THAI_FONT_PAGE		= 0xDE00  // Thai Windows 3.1 font page
   };
-
-  // https://github.com/Microsoft/Font-Validator/blob/520aaae/OTFontFileVal/val_OS2.cs#L644-L681
   font_page_t get_font_page () const
   { return (font_page_t) (version == 0 ? fsSelection & 0xFF00 : 0); }